Effects of dietary glycaemic index on adiposity, glucose homoeostasis, and plasma lipids in animals

Effect of Junk Food on Hormonal and Metabolic Manifestations in Polycystic Ovarian Syndrome Phenotypes: A Case-Control Study of Kashmiri Population

Polycystic ovarian syndrome is the most common endocrinopathy with heterogeneous symptomatology and diverse etiological links. Apart from genetic predisposition, environmental toxins, lifestyle, diet have been seen as contributing factors in shaping the disease. This study was taken to underpin the phenotypic status of PCOS in Kashmiri population and to compare their metabolic and endocrinological features. We explored the relationship between the junk food consumption patterns with the clinical features of PCOS phenotypes and controls. A total of 404 PCOS patients and 126 controls were recruited and cases were classified as per Rotterdam criteria. Anthropometric measurements and biochemical parameters of both cases and controls were taken. A detailed account on the type and frequency of outdoor foods eaten was focused and accordingly the study population was classified into voracious eaters, moderately eaters and rarely eaters of junk food. We found highest prevalence of phenotype A, n = 131 (32.8%) with full-blown symptoms in terms of obesity, IR, hirsutism, dyslipidemia and metabolic syndrome in our population. Phenotype D was found to be least prevalent n = 72 (17.7%) with milder form of symptoms. Our study is the first to unravel the phenotypic status of PCOS in Kashmiri population employing Rotterdam criteria and undertake dietary factor to relate with the pathogenesis of this disease. There was a notable association between an increasingly affluent diet, the presence of hirsutism, raised body mass index, obesity and metabolic syndrome in our population, making diet as an imperative factor to govern PCOS presentation. This study clearly implies the effect of unhealthy dietary habits to be associated with increasingly severe phenotype of PCOS, which can likely have implications on metabolic and fertility outcomes.

Saturated fatty acids as guest compounds in the annealing of high-amylose starch: Insights into fatty acid chain length and structural conformation

This study explores the effect of fatty acid chain length in regulating the structural changes and physicochemical properties of high-amylose maize starch (HAMS) induced by annealing with fatty acid solution (AFAS). AFAS was found to effectively regulate the conformation of amylose molecular chains within starch granules. Annealing with fatty acids of shorter chain length, such as lauric acid, promoted the formation of both double and single helices within HAMS granules. The single-helix fraction increased (up to 4.5 %) after AFAS treatment. HAMS modified with lauric acid exhibited the highest crystallinity (24.1 %). The level of structural changes varied for HAMS with shorter amylose chain length. Fatty acids with shorter chain lengths, such as lauric acid and myristic acid, induced higher levels of resistant starch (up to 65 %) under in vitro simulated digestion conditions. Pearson analysis revealed a significant negative correlation (p < 0.05) between the resistant starch content of the modified starch and the fatty-acid chain length complexed during AFAS. These findings suggest that the chain length of fatty acids affects the enzyme resistance of the modified starches, with shorter fatty-acid chain lengths being more effective in inducing ordered structures.

The impact of a low-carbohydrate (vs. low-fat) diet on fat mass loss in African American women is modulated by insulin sensitivity

OBJECTIVE

The objective of this study was to examine the independent and interactive effects of insulin sensitivity (SI), the acute insulin response to glucose, and diet on changes in fat mass (FM), resting and total energy expenditure (REE and TEE, respectively), and mechanical efficiency, during weight loss, in African American women with obesity.

METHODS

A total of 69 women were randomized to low-fat (55% carbohydrate [CHO], 20% fat) or low-CHO (20% CHO, 55% fat) hypocaloric diets for 10 weeks, followed by a 4-week weight-stabilization period (controlled feeding). SI and acute insulin response to glucose were measured at baseline with an intravenous glucose tolerance test; body composition was measured with bioimpedance analysis at baseline and week 10; and REE, TEE, and mechanical efficiency were measured with indirect calorimetry, doubly labeled water, and a submaximal bike test, respectively, at baseline and week 14.

RESULTS

Within the group with low SI, those on the low-CHO diet lost more weight (mean [SE], -6.6 [1.0] vs. -4.1 [1.4] kg; p = 0.076) and FM (-4.9 [0.9] vs. -2.1 [1.0] kg; p = 0.04) and experienced a lower reduction in REE (-48 [30] vs. -145 [30] kcal/day; p = 0.035) and TEE (mean [SE] 67 [56] vs. -230 [125] kcal/day; p = 0.009) compared with those on the low-fat diet.

CONCLUSIONS

A low-CHO diet leads to a greater FM loss in African American women with obesity and low SI, likely by minimizing the reduction in EE that follows weight loss.

Selective transcriptomic dysregulation of metabolic pathways in liver and retina by short- and long-term dietary hyperglycemia

A high glycemic index (HGI) diet induces hyperglycemia, a risk factor for diseases affecting multiple organ systems. Here, we evaluated tissue-specific adaptations in the liver and retina after feeding HGI diet to mice for 1 or 12 month. In the liver, genes associated with inflammation and fatty acid metabolism were altered within 1 month of HGI diet, whereas 12-month HGI diet-fed group showed dysregulated expression of cytochrome P450 genes and overexpression of lipogenic factors including Srebf1 and Elovl5. In contrast, retinal transcriptome exhibited HGI-related notable alterations in energy metabolism genes only after 12 months. Liver fatty acid profiles in HGI group revealed higher levels of monounsaturated and lower levels of saturated and polyunsaturated fatty acids. Additionally, HGI diet increased blood low-density lipoprotein, and diet-aging interactions affected expression of mitochondrial oxidative phosphorylation genes in the liver and disease-associated genes in retina. Thus, our findings provide new insights into retinal and hepatic adaptive mechanisms to dietary hyperglycemia.

White-brown adipose tissue interplay in polycystic ovary syndrome: Therapeutic avenues

This study highlights the therapeutic potential of activating brown adipose tissue (BAT) for managing polycystic ovary syndrome (PCOS), a prevalent endocrine disorder associated with metabolic and reproductive abnormalities. BAT plays a crucial role in regulating energy expenditure and systemic insulin sensitivity, making it an attractive target for the treatment of obesity and metabolic diseases. Recent research suggests that impaired BAT function and mass may contribute to the link between metabolic disturbances and reproductive issues in PCOS. Additionally, abnormal white adipose tissue (WAT) can exacerbate these conditions by releasing adipokines and nonesterified fatty acids. In this review, we explored the impact of WAT changes on BAT function in PCOS and discussed the potential of BAT activation as a therapeutic strategy to improve PCOS symptoms. We propose that BAT activation holds promise for managing PCOS; however, further research is needed to confirm its efficacy and to develop clinically feasible methods for BAT activation.

A genomics perspective of personalized prevention and management of obesity

This review discusses the landscape of personalized prevention and management of obesity from a nutrigenetics perspective. Focusing on macronutrient tailoring, we discuss the impact of genetic variation on responses to carbohydrate, lipid, protein, and fiber consumption. Our bioinformatic analysis of genomic variants guiding macronutrient intake revealed enrichment of pathways associated with circadian rhythm, melatonin metabolism, cholesterol and lipoprotein remodeling and PPAR signaling as potential targets of macronutrients for the management of obesity in relevant genetic backgrounds. Notably, our data-based in silico predictions suggest the potential of repurposing the SYK inhibitor fostamatinib for obesity treatment in relevant genetic profiles. In addition to dietary considerations, we address genetic variations guiding lifestyle changes in weight management, including exercise and chrononutrition. Finally, we emphasize the need for a refined understanding and expanded research into the complex genetic landscape underlying obesity and its management.

Obesity-Resistant Mice on a High-Fat Diet Display a Distinct Phenotype Linked to Enhanced Lipid Metabolism

Individually, metabolic variations can significantly influence predisposition to obesity in the form of the obesity-prone (super-responders) and obesity-resistant (non-responders) phenotypes in response to modern calorie-dense diets. In this study, C57BL/6J mice (n = 76) were randomly assigned to either a low-fat diet (LFD) or a high-fat diet (HFD) for 6 weeks, followed by selection of the normally obese (HFD), non-responders (NR), super-responders (SR), or super-responders switched back to the low-fat diet (SR-LFD) for an additional 8 weeks. SR mice showed the highest gains in body weight, lean and fat body mass, and total and free water, in part due to increased feed efficiency, despite having a respiratory exchange ratio (RER) similar to that of NR mice. A switch to the LFD was sufficient to revert most of the observed physiological changes in the SR-LFD mice; however, voluntary physical activity and exercise capacity did not return to the basal level. NR mice showed the highest food intake, lowest feed efficiency, increased oxygen consumption during the light (rest) cycle, increased physical activity during the dark (active) cycle, and increased heat production during both cycles. These variations were observed in the absence of changes in food intake and fecal parameters; however, NR fecal lipid content was lower, and the NR fecal microbiome profile was characterized by reduced abundance of Actinobacteria. Taken together, our findings suggest that NR mice showed an increased ability to metabolize excessive dietary fats in skeletal muscle at the expense of reduced exercise capacity that persisted for the duration of the study. These findings underscore the need for further comprehensive investigations into the mechanisms of obesity resistance, as they hold potential implications for weight-loss strategies in human subjects.

Carbohydrate-insulin model: does the conventional view of obesity reverse cause and effect?

Conventional obesity treatment, based on the First Law of Thermodynamics, assumes that excess body fat gain is driven by overeating, and that all calories are metabolically alike in this regard. Hence, to lose weight one must ultimately eat less and move more. However, this prescription rarely succeeds over the long term, in part because calorie restriction elicits predictable biological responses that oppose ongoing weight loss. The carbohydrate-insulin model posits the opposite causal direction: overeating doesn't drive body fat increase; instead, the process of storing excess fat drives overeating. A diet high in rapidly digestible carbohydrates raises the insulin-to-glucagon ratio, shifting energy partitioning towards storage in adipose, leaving fewer calories for metabolically active and fuel sensing tissues. Consequently, hunger increases, and metabolic rate slows in the body's attempt to conserve energy. A small shift in substrate partitioning though this mechanism could account for the slow but progressive weight gain characteristic of common forms of obesity. From this perspective, the conventional calorie-restricted, low-fat diet amounts to symptomatic treatment, failing to target the underlying predisposition towards excess fat deposition. A dietary strategy to lower insulin secretion may increase the effectiveness of long-term weight management and chronic disease prevention. This article is part of a discussion meeting issue 'Causes of obesity: theories, conjectures and evidence (Part II)'.

Moderating "the great debate": The carbohydrate-insulin vs. the energy balance models of obesity

The increased prevalence of obesity in recent decades is a topic of great scientific and medical interest, but despite many advances, the causes of this increase have not been adequately identified. In this context, two conflicting models for obesity-the carbohydrate-insulin model (CIM) and the energy balance model (EBM)-are being vigorously debated by distinct cohorts of experts in the field. The goal of this perspective is to assess this "conflict of models" from a neutral perspective. I conclude that although both models have produced useful insights, they differ fundamentally in what they seek to explain, and neither has yet provided a validated mechanistic account for the rising obesity prevalence in some but not all members of the population. Rather than engaging in such debates over competing models, the field should be more focused on establishing specific mechanistic insights in identified patient groups and, eventually, actionable interventions based on them.

Continuous glucose monitoring reveals similar glycemic variability in individuals with obesity despite increased HOMA-IR

Background/aims

Continuous glucose monitoring is a well-tolerated and versatile tool for management of diabetes and metabolic disease. While its use appears to be feasible to monitor glycemic profiles in diabetics, there is a paucity of data in individuals with obesity and normal glucose tolerance. The aim of this study is to investigate glucose fluctuations and insulin resistance patterns in normoglycemic participants with obesity vs. without obesity and contextualize these results against leading models for obesity.

Materials and methods

We designed a prospective, observational pilot study of two cohorts including 14 normoglycemic participants with obesity and 14 normoglycemic participants without obesity. Participants were monitored with continuous glucose monitoring (CGM) for five consecutive days. Insulin resistance levels were measured and glucometric data were extracted from CGM for all participants.

Results

Fasting serum insulin and homeostasis model assessment of insulin resistance (HOMA-IR) were significantly higher in the group with obesity (P < 0.05). While the group with obesity had a higher mean blood glucose (MBG), mean amplitude of glycemic excursions (MAGE), and continuous overall glycemic action-1 h (CONGA-1), these differences were not significant. On univariate linear regression, insulin resistance (HOMA-IR) was associated with body mass index (BMI), waist circumference (WC), cohort with obesity, cohort consuming a high glycemic diet, hemoglobin A1c (HbA1c), and fasting insulin levels. WC and fasting insulin levels remained predictors of HOMA-IR in our multivariable model.

Conclusion

While there is much excitement surrounding the use of commercial CGM products in obesity management, our results suggest that fasting insulin and HOMA-IR values may be more clinically useful than CGM data alone.

Effects of high-pressure processing on the physicochemical properties and glycemic index of fruit puree in a hyperglycemia mouse model

BACKGROUND

In this study, the duration of high-pressure processing (HPP) required to achieve a 5 log reduction of Escherichia coli O157:H7 in fruit purees was evaluated. Banana, cantaloupe, and dragon fruit purees were subjected to HPP at 600 MPa for 300, 270, and 270 s, respectively, and their physicochemical properties and enzyme activities were then analysed. Diabetic mice were fed fresh and HPP-treated purees to observe their effects on the glycemic index (GI) and postprandial blood glucose response.

RESULTS

Compared with their fresh counterparts, the HPP-treated banana and dragon fruit purees exhibited significantly higher viscosities, lower glucose concentrations, and higher glucose dialysis retardation indices and showed disrupted sucrose invertase and polygalacturonase activities. The GI and postprandial blood glucose response were not significantly different between the fresh and HPP-treated cantaloupe purees. By contrast, the peak time of glucose response (T_max ) was delayed from 30 min to 60 min, and the area under the receiver operating characteristic curve was reduced by 40% in the mice fed HPP-treated banana and dragon fruit purees. The GIs of the HPP-treated banana and dragon fruit purees (were 50.3 and 44.8, respectively) were significantly lower than those of their fresh counterparts (85.1 and 75.2, respectively).

CONCLUSION

HPP can change the physicochemical properties of fruit purees, resulting in stabilized blood glucose levels and lower GIs after consumption. Therefore, purees processed in this manner would benefit consumers and patients with diabetes/pre-diabetes who need to maintain stable blood glucose levels (Fig. S1). © 2022 Society of Chemical Industry.

Factors Associated With Treatment Adherence to a Lifestyle Intervention Program for Children With Obesity: The Experience of a Large Tertiary Care Pediatric Hospital

Early dropout and treatment adherence are main challenges in the treatment of children with obesity. The aim of this study was to identify factors associated with attrition and adherence to weight loss intervention program. We retrospectively reviewed the medical records of all the children who entered the program for pediatric weight loss over 5 years and retrieved demographic and clinical characteristics. Attrition and adherence were documented. Ninety-two of the 248 enrolled children (52% women, mean age 11.1 ± 3.9 years, mean body mass index 31.1 ± 7 kg/m²) dropped out (37%). Dropping out correlated with male sex, low parental education, and self-referral to the clinic (P < .05 for all). Adherence correlated with older age and the mother's healthy lifestyle (P < .05 for all). Sex, parental education, and referral source may predict treatment attrition. Early recognition of children at risk of attrition may help to facilitate better care of those children.

The association of Carbohydrate Quality Index with cardiovascular disease risk factors among women with overweight and obesity: A cross-sectional study

Purpose

Diet is one of the most important factors influencing cardiovascular disease (CVD). The negative relationship between carbohydrate intake with lipid profiles and body weight has been previously investigated. However, this is the first study seeking to assess the association of carbohydrate quality index (CQI) with CVD risk factors.

Methods

This cross-sectional study was conducted on 291 Iranian overweight and obese women, with a body mass index (BMI) ranging between 25 and 40 kg/m², and aged 18–48 years. CQI scores were calculated by using a validated 168-item semi-quantitative food frequency questionnaire (FFQ). Biochemical and anthropometric measures were assessed using standard methods, and bioelectrical impedance was used to measure body composition.

Results

We observed that fruits (P < 0.001), vegetables (P < 0.001), and protein (P = 0.002) intake were higher in participants with a higher score of the CQI. When we adjusted for potential confounders, we observed that the CQI was negatively related to systolic blood pressure (SBP) (β = −6.10; 95% CI = −10.11, −2.10; P = 0.003) and DBP (β = −3.11; 95% CI = −6.15, −0.08; P = 0.04). Also, greater adherence to a high CQI dietary pattern, compared to the reference group, was negatively related to HOMA-IR (β = −0.53; 95% CI = −0.94, −0.12) (P for trend = 0.01), WC (β = −3.18; 95% CI = −6.26, −0.10) (P for trend = 0.04), BMI (β = −1.21; 95% CI = −2.50, 0.07) (P for trend = 0.06), and BF (β = −2.06; 95% CI = −3.82, −0.30) (P for trend = 0.02).

Conclusion

In line with previous studies, the CQI was inversely associated with blood pressure, WC, BMI, and BF. Further prospective and clinical trial studies are suggested to confirm these data.

Competing paradigms of obesity pathogenesis: energy balance versus carbohydrate-insulin models

The obesity pandemic continues unabated despite a persistent public health campaign to decrease energy intake (“eat less”) and increase energy expenditure (“move more”). One explanation for this failure is that the current approach, based on the notion of energy balance, has not been adequately embraced by the public. Another possibility is that this approach rests on an erroneous paradigm. A new formulation of the energy balance model (EBM), like prior versions, considers overeating (energy intake > expenditure) the primary cause of obesity, incorporating an emphasis on “complex endocrine, metabolic, and nervous system signals” that control food intake below conscious level. This model attributes rising obesity prevalence to inexpensive, convenient, energy-dense, “ultra-processed” foods high in fat and sugar. An alternative view, the carbohydrate-insulin model (CIM), proposes that hormonal responses to highly processed carbohydrates shift energy partitioning toward deposition in adipose tissue, leaving fewer calories available for the body’s metabolic needs. Thus, increasing adiposity causes overeating to compensate for the sequestered calories. Here, we highlight robust contrasts in how the EBM and CIM view obesity pathophysiology and consider deficiencies in the EBM that impede paradigm testing and refinement. Rectifying these deficiencies should assume priority, as a constructive paradigm clash is needed to resolve long-standing scientific controversies and inform the design of new models to guide prevention and treatment. Nevertheless, public health action need not await resolution of this debate, as both models target processed carbohydrates as major drivers of obesity.

Glucose tolerance of iguanas is affected by high-sugar diets in the lab and supplemental feeding by ecotourists in the wild

There is great interspecific variation in the nutritional composition of natural diets, and the varied nutritional content is physiologically tolerated because of evolutionarily based balances between diet composition and processing ability. However, as a result of landscape change and human exposure, unnatural diets are becoming widespread among wildlife without the necessary time for evolutionary matching between the diet and its processing. We tested how a controlled, unnatural high glucose diet affects glucose tolerance using captive green iguanas, and we performed similar glucose tolerance tests on wild Northern Bahamian rock iguanas that are either frequently fed grapes by tourists or experience no such supplementation. We evaluated both short and longer-term blood glucose responses and corticosterone (CORT) concentrations as changes have been associated with altered diets. Experimental glucose supplementation in the laboratory and tourist feeding in the wild both significantly affected glucose metabolism. When iguanas received a glucose-rich diet, we found greater acute increases in blood glucose following a glucose challenge. Relative to unfed iguanas, tourist-fed iguanas had significantly lower baseline CORT, higher baseline blood glucose, and slower returns to baseline glucose levels following a glucose challenge. Therefore, unnatural consumption of high amounts of glucose alters glucose metabolism in laboratory iguanas with short-term glucose treatment and free-living iguanas exposed to long-term feeding by tourists. Based on these results and the increasing prevalence of anthropogenically altered wildlife diets, the consequences of dietary changes on glucose metabolism should be further investigated across species, as such changes in glucose metabolism have health consequences in humans (e.g. diabetes).

Habitual- and Meal-Specific Carbohydrate Quality Index and Their Relation to Metabolic Syndrome in a Sample of Iranian Adults

AIM

Most studies on diet quality have focused on the habitual and overall intake of foods without considering intakes at specific eating occasions. This study aimed to assess the association between habitual- and meal-specific carbohydrate quality index (CQI) and metabolic syndrome (MetS) in Iranian adults.

METHODS

In this cross-sectional study, data from 850 participants were analyzed. Dietary information was obtained from a 3-day nonconsecutive 24 h recall. CQI was calculated from three criteria: dietary fiber, glycemic index, and solid carbohydrate/total carbohydrate ratio. The association between CQI and MetS was assessed by logistic regression.

RESULTS

The prevalences of MetS in the lowest and highest tertile of CQI were 30.1 and 33.7, respectively (P = 0.6). In habitual diet and all the three meals, we failed to find any significant association between tertiles of CQI and MetS either before or after adjustment for covariates. However, in the habitual meals [odds ratio (OR): 0.69, 95% CI: 0.47-0.96] and lunch meals (OR: 0.66; 95% CI: 0.47-0.94), the highest CQI in comparison to the lowest one, significantly decreased the low high-density lipoprotein (HDL). In addition, the trend of low-HDL with CQI in habitual meal and lunch meal was statistically significant.

CONCLUSION

The results of this study showed that CQI was not associated with MetS and its components. Further investigations into the mechanisms underlying the role of carbohydrate quality in developing metabolic disorders are warranted.

Stimulated Insulin Secretion Predicts Changes in Body Composition Following Weight Loss in Adults with High BMI

BACKGROUND

The aim of obesity treatment is to promote loss of fat relative to lean mass. However, body composition changes with calorie restriction differ among individuals.

OBJECTIVES

The goal of this study was to test the hypothesis that insulin secretion predicts body composition changes among young and middle-age adults with high BMI (in kg/m2) following major weight loss.

METHODS

Exploratory analyses were conducted with pre-randomization data from 2 large feeding trials: the Framingham, Boston, Bloomington, Birmingham, and Baylor study (FB4; n = 82, 43.9% women, BMI ≥27) and the Framingham State Food Study [(FS)2; n = 161, 69.6% women, BMI ≥25]. Participants in the 2 trials consumed calorie-restricted moderate-carbohydrate or very-low-carbohydrate diets to produce 12-18% weight loss in ∼14 wk or 10-14% in ∼10 wk, respectively. We determined insulin concentration 30 min after a 75-g oral glucose load (insulin-30) as a measure of insulin secretion and HOMA-IR as a measure of insulin resistance at baseline. Body composition was determined by DXA at baseline and post-weight loss. Associations were analyzed using general linear models with adjustment for covariates.

RESULTS

In FB4, higher insulin-30 was associated with a smaller decrease in fat mass (0.441 kg per 100 μIU/mL increment in baseline insulin-30; P = 0.005; -1.20-kg mean difference between the first compared with the fifth group of insulin-30) and a larger decrease in lean mass (-0.465 kg per 100 μIU/mL; P = 0.004; 1.27-kg difference). Participants with higher insulin-30 lost a smaller proportion of weight loss as fat (-3.37% per 100 μIU/mL; P = 0.003; 9.20% difference). Greater HOMA-IR was also significantly associated with adverse body composition changes. Results from (FS)2 were qualitatively similar but of a smaller magnitude.

CONCLUSIONS

Baseline insulin dynamics predict substantial individual differences in body composition following weight loss. These findings may inform understanding of the pathophysiological basis for weight regain and the design of more effective obesity treatment. Registered at clinicaltrials.gov as NCT03394664 and NCT02068885.

Complexation between burdock holocellulose nanocrystals and corn starch: gelatinization properties, microstructure, and digestibility in vitro

Holocellulose nanocrystals (hCNCs), with hydrodynamic diameters (D_Z) ranging from about 600 to 200 nm, were prepared by treating burdock insoluble dietary fiber (IDF) with enzymes and ultrasonic power. It was revealed that hCNCs improved the viscosity of corn starch (CS) during pasting and inhibited its short-term retrogradation. Besides, the crystallinity, short-range order of the double helix, viscoelastic properties, and microstructure compactness of CS gels improved remarkably in the presence of burdock hCNCs. These effects were both size- and dose-dependent, which primarily originated from the hydrogen bonding between hCNCs and amylopectin or leached amylose. In this regard, the digestion of CS gels containing hCNCs was remarkably retarded because of the reduced accessibility of digestive enzymes to the glycosidic bonds. Therefore, burdock hCNCs, prepared from natural resources using green techniques, hold potential applications in functional foods of a low glycemic index.

The carbohydrate-insulin model: a physiological perspective on the obesity pandemic

According to a commonly held view, the obesity pandemic is caused by overconsumption of modern, highly palatable, energy-dense processed foods, exacerbated by a sedentary lifestyle. However, obesity rates remain at historic highs, despite a persistent focus on eating less and moving more, as guided by the energy balance model (EBM). This public health failure may arise from a fundamental limitation of the EBM itself. Conceptualizing obesity as a disorder of energy balance restates a principle of physics without considering the biological mechanisms that promote weight gain. An alternative paradigm, the carbohydrate-insulin model (CIM), proposes a reversal of causal direction. According to the CIM, increasing fat deposition in the body-resulting from the hormonal responses to a high-glycemic-load diet-drives positive energy balance. The CIM provides a conceptual framework with testable hypotheses for how various modifiable factors influence energy balance and fat storage. Rigorous research is needed to compare the validity of these 2 models, which have substantially different implications for obesity management, and to generate new models that best encompass the evidence.

Diet and exercise in NAFLD/NASH: Beyond the obvious

Lifestyle represents the most relevant factor for non-alcoholic fatty liver disease (NAFLD) as the hepatic manifestation of the metabolic syndrome. Although a tremendous body of clinical and preclinical data on the effectiveness of dietary and lifestyle interventions exist, the complexity of this topic makes firm and evidence-based clinical recommendations for nutrition and exercise in NAFLD difficult. The aim of this review is to guide readers through the labyrinth of recent scientific findings on diet and exercise in NAFLD and non-alcoholic steatohepatitis (NASH), summarizing "obvious" findings in a holistic manner and simultaneously highlighting stimulating aspects of clinical and translational research "beyond the obvious". Specifically, the importance of calorie restriction regardless of dietary composition and evidence from low-carbohydrate diets to target the incidence and severity of NAFLD are discussed. The aspect of ketogenesis-potentially achieved via intermittent calorie restriction-seems to be a central aspect of these diets warranting further investigation. Interactions of diet and exercise with the gut microbiota and the individual genetic background need to be comprehensively understood in order to develop personalized dietary concepts and exercise strategies for patients with NAFLD/NASH.

Evaluation of the Obesity Prevention, Blood Glucose, and Blood Lipid Control of Vietnamese Rice Varieties in High-Fat Diet-Induced Obese Mice

Five Vietnamese rice varieties, which differ in their basic chemical composition (starch content, amylose content, fiber content) including polished rices and whole grain rices, were chosen for this study. High-fat diet-induced obesity, using these rice, was subjected to in vivo experiments to evaluate the effects of body weight gain, caloric intake, postprandial blood glucose level (PBGL), and glycemic index (GI) in tested mice groups. PBGL peaks appeared at 30^th minute after eating, and GI of each experimental group was ranked in order as GN > TL > HR > GM > LĐ and GN > LT > HR > LĐ > GM, respectively, in which, brown rice (LĐ) and germinated brown rice (GM) had low GI. Furthermore, these rice varieties caused the lowest LDL cholesterol and the ratio of LDL/HDL cholesterols in mice. In this study, the higher the amylose and fiber contents were, the lower glycemic index, triglycerides, LDL, and LDL/HDL values were. The golden flower glutinous rice (GN), with low amylose and fiber content, gave worse blood lipid parameters than that of GM and LĐ. Histopathological studies of white adipose and liver tissues showed that LĐ and GM significantly reduced the symptoms of obesity and fatty liver compared with the others, especially compared to GN. The results obtained from this study help patients with overweight, obesity, and type 2 diabetes choose the right rice variety for their daily diet to be able to control their diseases.

Improving nutrition for the prevention of gestational diabetes: Current status and perspectives

Gestational diabetes mellitus (GDM) is a common complication of pregnancy and a serious public health problem. It carries significant risks of short-term and long-term adverse health effects for both mothers and their children. Risk factors, especially modifiable risk factors, must be considered to prevent GDM and its consequences. Observational studies have identified several nutritional and lifestyle factors associated with the risk of GDM. The results of intervention studies examining the effects of diet and lifestyle on the prevention of GDM are contradictory. Differences in the study populations, types and intensity of intervention, time frame of the intervention, and diagnostic criteria for GDM may explain the heterogeneity in the results of intervention studies. This review provides an overview of new diets and other factors that may help prevent GDM. The main results of epidemiological studies assessing the risk factors for GDM, as well as the results and methodological problems of intervention studies on the prevention of GDM and their meta-analyses, are discussed. In addition, the evidence that gene and lifestyle interactions influence the development of GDM, as well as prospects for increasing the effectiveness of interventions designed to prevent GDM, including new data on the possible uses of personalized diet therapy, are highlighted.

The effect of high-pressure processing on reducing the glycaemic index of atemoya puree

BACKGROUND

This study investigated the effects of high-pressure processing (HPP) on the glycaemic index (GI) of atemoya puree (AP) in rats. Sprague-Dawley rats were fed with unprocessed and high-pressure processed atemoya puree (HPP-AP), and the GIs for the unprocessed AP and HPP-AP were calculated from changes in blood glucose concentrations within 2 h after meals. The physicochemical properties of AP were analysed to understand the mechanism affecting its GI.

RESULTS

The results showed that HPP (600 MPa for 15 min) could delay increase in postprandial blood glucose levels, decrease the peak value of postprandial blood glucose by 76.1%, and significantly decrease the GI of AP to 49.8 in the experimental group compared to 65.4 in the control group. HPP did not exert a significant effect on the glucose and pectin contents of AP, but it increased the viscosity of the puree and its dietary fibre content and delayed the time of peak glucose response. In the analysis of enzymes of the puree, we found that HPP significantly decreased the activities of sucrose invertase, pectin methylesterase and polygalacturonase, thereby decreasing the rate of glucose generation in the puree and stabilizing the pectin structure, which decreased the absorption of glucose by the small intestine, thus decreasing the GI value.

CONCLUSION

Our findings suggest that HPP technology could effectively delay increase in postprandial blood glucose levels and decrease the GI value of AP, thus having a potential application in developing atemoya puree products with low GI. © 2020 Society of Chemical Industry.

Do Lower-Carbohydrate Diets Increase Total Energy Expenditure? An Updated and Reanalyzed Meta-Analysis of 29 Controlled-Feeding Studies

BACKGROUND

The effect of macronutrient composition on total energy expenditure (TEE) remains controversial, with divergent findings among studies. One source of heterogeneity may be study duration, as physiological adaptation to lower carbohydrate intake may require 2 to 3 wk.

OBJECTIVE

We tested the hypothesis that the effects of carbohydrate [expressed as % of energy intake (EI)] on TEE vary with time.

METHODS

The sample included trials from a previous meta-analysis and new trials identified in a PubMed search through 9 March 2020 comparing lower- and higher-carbohydrate diets, controlled for EI or body weight. Three reviewers independently extracted data and reconciled discrepancies. Effects on TEE were pooled using inverse-variance-weighted meta-analysis, with between-study heterogeneity assessed using the I2 statistic. Meta-regression was used to quantify the influence of study duration, dichotomized at 2.5 wk.

RESULTS

The 29 trials ranged in duration from 1 to 140 d (median: 4 d) and included 617 participants. Difference in carbohydrate between intervention arms ranged from 8% to 77% EI (median: 30%). Compared with reported findings in the prior analysis (I2 = 32.2%), we found greater heterogeneity (I2 = 90.9% in the reanalysis, 81.6% in the updated analysis). Study duration modified the diet effect on TEE (P < 0.001). Among 23 shorter trials, TEE was reduced on lower-carbohydrate diets (-50.0 kcal/d; 95% CI: -77.4, -22.6 kcal/d) with substantial heterogeneity (I2 = 69.8). Among 6 longer trials, TEE was increased on low-carbohydrate diets (135.4 kcal/d; 95% CI: 72.0, 198.7 kcal/d) with low heterogeneity (I2 = 26.4). Expressed per 10% decrease in carbohydrate as %EI, the TEE effects in shorter and longer trials were -14.5 kcal/d and 50.4 kcal/d, respectively. Findings were materially unchanged in sensitivity analyses.

CONCLUSIONS

Lower-carbohydrate diets transiently reduce TEE, with a larger increase after ∼2.5 wk. These findings highlight the importance of longer trials to understand chronic macronutrient effects and suggest a mechanism whereby lower-carbohydrate diets may facilitate weight loss.

Suppression of Insulin Secretion in the Treatment of Obesity: A Systematic Review and Meta-Analysis

OBJECTIVE

This proof-of-concept study aimed to evaluate the efficacy and safety of suppression of insulin secretion in the treatment of obesity.

METHODS

A search of PubMed, Embase, and Cochrane databases was performed to identify randomized controlled trials (up to January 1, 2020) that used drugs that directly suppress insulin secretion (diazoxide or octreotide) in the treatment of obesity. The extracted data were analyzed using random-effects meta-analysis.

RESULTS

A total of seven randomized controlled trials were included, with four using diazoxide and three using octreotide to suppress insulin secretion. Suppression of insulin secretion significantly reduced fasting insulin level (mean difference: -3.94 mIU/L; 95% CI: -7.40 to -0.47) but slightly increased fasting blood glucose level (mean difference: 0.48 mmol/L; 95% CI: 0.24 to 0.72). Following the suppression of insulin secretion, significant reductions in body weight (mean difference: -3.19 kg; 95% CI: -5.71 to -0.66), BMI (mean difference: -1.65 kg/m² ; 95% CI: -2.41 to -0.90), and fat mass (mean difference: -5.92 kg; 95% CI: -8.28 to -3.56) were observed compared with placebo in the pooled data. No significant difference in fat-free mass was observed (mean difference: 0.56 kg; 95% CI: -0.40 to 1.52).

CONCLUSIONS

Results suggest that suppression of insulin secretion may lead to reduced body weight and fat mass with slightly increased blood glucose in individuals with obesity.

The Two Faces of Wheat

Wheat-based foods have been staple foods since about 10,000 years and constitute a major source of energy, dietary fiber, and micronutrients for the world population. The role of wheat in our diet, however, has recently been scrutinized by pseudoscientific books and media reports promoting the overall impression that wheat consumption makes people sick, stupid, fat, and addicted. Consequently, numerous consumers in Western countries have started to question their dietary habits related to wheat consumption and voluntarily decided to adopt a wheat-free diet without a medical diagnosis of any wheat-related disorder (WRD), such as celiac disease, wheat allergy, or non-celiac gluten sensitivity. The aim of this review is to achieve an objective judgment of the positive aspects of wheat consumption as well as adverse effects for individuals suffering from WRDs. The first part presents wheat constituents and their positive nutritional value, in particular, the consumption of products from whole-grain flours. The second part is focused on WRDs that affect predisposed individuals and can be treated with a gluten-free or -reduced diet. Based on all available scientific knowledge, wheat consumption is safe and healthy for the vast majority of people. There is no scientific evidence to support that the general population would benefit from a wheat-free diet.

Genetic determinants of obesity heterogeneity in type II diabetes

Background

Although obesity is considered as the main cause of Type II diabetes (T2DM), non-obese individuals may still develop T2DM and obese individuals may not.

Method

The mRNA expression of PI3K/AKT axis from 100 non-obese and obese participants with insulin sensitivity and insulin resistance states were compared in this study toward the understanding of obesity heterogeneity molecular mechanism.

Result

In present study, there was no statistically significant difference in gene expression levels of IRS1 and PTEN between groups, whereas PI3K, AKT2 and GLUT4 genes were expressed at a lower level in obese diabetic group compared to other groups and were statistically significant. PDK1 gene was expressed at a higher level in non-obese diabetic group compared to obese diabetic and non-obese non-diabetics groups. No statistically significant difference was identified in gene expression pattern of PI3K/AKT pathway between obese non-diabetics and non-obese non-diabetics.

Conclusion

The components of PI3K/AKT pathway which is related to the fasting state, showed reduced expression in obese diabetic group due to the chronic over-nutrition which may induced insensitivity and reduced gene expression. The pathogenesis of insulin resistance in the absence of obesity in non-obese diabetic group could be due to disturbance in another pathway related to the non-fasting state like gluconeogenesis. Therefore, the molecular mechanism of insulin signalling in non-obese diabetic individuals is different from obese diabetics which more investigations are required to study insulin signalling pathways in greater depth, in order to assess nutritional factors, contribute to insulin resistance in obese diabetic and non-obese diabetic individuals.

Effects of Dietary Carbohydrate Content on Circulating Metabolic Fuel Availability in the Postprandial State

Context

According to the carbohydrate-insulin model of obesity, an elevated insulin-to-glucagon ratio in response to a high-carbohydrate diet directs metabolic fuels toward storage, resulting in lower circulating energy.

Objective

To determine differences in total circulating energy post-meal related to dietary carbohydrate.

Design

Ancillary study within the Framingham State Food Study.

Setting

University community.

Participants

29 adults (aged 20 to 65 years) with overweight or obesity (body mass index ≥25 kg/m²)

Intervention

After achieving 10% to 14% weight loss on a run-in diet, participants were randomized to weight-loss-maintenance test diets varying in carbohydrate content (high-carbohydrate, 60% of total energy, n = 11; moderate-carbohydrate, 40%, n = 8; low-carbohydrate, 20%, n = 10) and controlled for protein (20%). During 24-hour metabolic ward admissions between 10 and 15 weeks on the test diets, metabolic fuels and hormones were measured.

Main Outcome Measure

Energy availability (EA) based on energy content of blood glucose, beta-hydroxybutyrate, and free fatty acids, in the late postprandial period (180 to 300 minutes). Insulin at 30 minutes into the test meal (Meal Insulin-30) was measured as an effect modifier.

Results

Insulin-to-glucagon ratio was 7-fold higher in participants on the high- vs low-carbohydrate diet (2.5 and 0.36, respectively). Late postprandial EA was 0.58 kcal/L lower on the high- vs low-carbohydrate diet (P < 0.0001), primarily related to suppression of free fatty acids. Early postprandial EA (30 to 180 minutes) declined fastest in the high-carbohydrate group, and Meal Insulin-30 modified this diet effect.

Conclusions

During weight-loss maintenance on a high-carbohydrate diet, late postprandial EA is reduced, consistent with the carbohydrate-insulin model.

Impact of dietary intake of resistant starch on obesity and associated metabolic profiles in human: a systematic review of the literature

As a global public health issue with an increasing prevalence, obesity is related to several metabolic disorders, but is largely preventable. Resistant starch (RS), the indigestible portion of starch, has been studied for its potential effects on reducing obesity. This systematic review aimed to investigate the effect of dietary intake of RS on obesity development and related metabolic profiles in human, including body weight and composition, energy intake and satiety, lipid profiles, blood glucose and insulin, and other blood biomarkers. Eleven peer-reviewed articles published in English between 2000 and 2019 were identified after screening using CENTRAL, MEDLINE, and CINAHL Plus. Based on the results, RS intake had no direct effect on body weight and body composition. Evidence for its effect on reducing energy intake and increasing satiety, as well as improving lipid profiles was inconsistent. Beneficial effects of RS intake on several blood biomarkers were supported, indicating its regulatory roles in blood glucose homeostasis, insulin sensitivity, and gut hormone concentrations. Specifically, five out of the eight articles measuring blood glucose reported a decrease in either fasting or postprandial glucose levels; two out of the three articles measuring insulin sensitivity indicated a significant improvement after RS supplementation; studies measuring gut hormone concentrations including glucagon-like peptide 1 (GLP-1), and peptide YY (PYY) also showed significant improvements after RS interventions. In conclusion, the effect of dietary intake of RS on obesity and its related metabolic complications was not conclusive. Further research with larger sample sizes and longer duration is warranted.

A low glycemic diet protects disease-prone Nrf2-deficient mice against age-related macular degeneration

Age-related macular degeneration (AMD) is a major blinding disease, affecting over 14% of the elderly. Risk for AMD is related to age, diet, environment, and genetics. Dietary modulation of AMD risk is a promising treatment modality, but requires appropriate animal models to demonstrate advantages of diet. Mice lacking the antioxidant transcription factor Nrf2 (Nfe2l2) develop age-related retinopathy relevant to human AMD. Here we evaluated the effect of consuming high glycemic (HG) or low glycemic (LG) diets until 18-months of age on development of features relevant to AMD in Nrf2-null mice. Nrf2-null mice that consumed HG diets developed atrophic AMD, characterized by photoreceptor degeneration, retinal pigment epithelium (RPE) atrophy and pigmentary abnormalities, basal laminar deposits, and loss of the choriocapillaris. In contrast, Nrf2-null-mice that consumed LG diets did not develop retinal disease phenotypes. Consumption of HG diets was associated with accumulation of advanced glycation end-products in the RPE and systemically, whereas consumption of the LG diet was associated with increased levels of anti-glycative and anti-oxidative detoxification machinery. Together our data indicate that the Nrf2-null HG mouse is a good model for atrophic AMD studies and that the LG diet can activate protective pathways to prevent AMD, even in a genetically predisposed animal.

The carbohydrate-insulin model does not explain the impact of varying dietary macronutrients on the body weight and adiposity of mice

Objectives

The carbohydrate-insulin model (CIM) predicts that increases in fasting and post-prandial insulin in response to dietary carbohydrates stimulate energy intake and lower energy expenditures, leading to positive energy balance and weight gain. The objective of the present study was to directly test the CIM's predictions using C57BL/6 mice.

Methods

Diets were designed by altering dietary carbohydrates with either fixed protein or fat content and were fed to C57BL/6 mice acutely or chronically for 12 weeks. The body weight, body composition, food intake, and energy expenditures of the mice were measured. Their fasting and post-prandial glucose and insulin levels were also measured. RNA-seq was performed on RNA from the hypothalamus and subcutaneous white adipose tissue. Pathway analysis was conducted using IPA.

Results

Only the post-prandial insulin and fasting glucose levels followed the CIM's predictions. The lipolysis and leptin signaling pathways in the sWAT were inhibited in relation to the elevated fasting insulin, supporting the CIM's predicted impact of high insulin. However, because higher fasting insulin was unrelated to carbohydrate intake, the overall pattern did not support the model. Moreover, the hypothalamic hunger pathways were inhibited in relation to the increased fasting insulin, and the energy intake was not increased. The browning pathway in the sWAT was inhibited at higher insulin levels, but the daily energy expenditure was not altered.

Conclusions

Two of the predictions were partially supported (and hence also partially not supported) and the other three predictions were not supported. We conclude that the CIM does not explain the impact of dietary macronutrients on adiposity in mice.

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Higher fasting insulin related to inhibited lipolysis and leptin pathways in sWAT, supporting CIM.

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Higher fasting insulin related to inhibited hypothalamic hunger pathway, contrasting CIM.

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Fasting insulin decreased with higher dietary carbohydrate, overall contrasting CIM.

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Higher dietary carbohydrate did not lead to greater EI/adiposity, or lowered EE.

The Gastrointestinal Tract as Prime Site for Cardiometabolic Protection by Dietary Polyphenols

Substantial evidence from nutritional epidemiology links polyphenol-rich diets with reduced incidence of chronic disorders; however, biological mechanisms underlying polyphenol-disease relations remain enigmatic. Emerging evidence is beginning to unmask the contribution of the gastrointestinal tract on whole-body energy homeostasis, suggesting that the intestine may be a prime target for intervention and a fundamental site for the metabolic actions of polyphenols. During their transit through the gastrointestinal tract, polyphenols may activate enteric nutrient sensors ensuing appropriate responses from other peripheral organs to regulate metabolic homeostasis. Furthermore, polyphenols can modulate the absorption of glucose, attenuating exaggerated hormonal responses and metabolic imbalances. Polyphenols that escape absorption are metabolized by the gut microbiota and the resulting catabolites may act locally, activating nuclear receptors that control enteric functions such as intestinal permeability. Finally, polyphenols modulate gut microbial ecology, which can have profound effects on cardiometabolic health.

Dairy fat intake and risk of type 2 diabetes in 3 cohorts of US men and women

BACKGROUND

Previous studies have examined dairy products with various fat contents in relation to type 2 diabetes (T2D) risk, although data regarding dairy fat intake per se are sparse.

OBJECTIVES

We aimed to evaluate the association between dairy fat intake and risk of T2D in 3 prospective cohorts. We also examined associations for isocalorically replacing dairy fat with other macronutrients.

METHODS

We prospectively followed 41,808 men in the Health Professionals Follow-Up Study (HPFS; 1986-2012), 65,929 women in the Nurses' Health Study (NHS; 1984-2012), and 89,565 women in the NHS II (1991-2013). Diet was assessed quadrennially using validated FFQs. Fat intake from dairy products and other relevant sources was expressed as percentage of total energy. Self-reported incident T2D cases were confirmed using validated supplementary questionnaires. Time-dependent Cox proportional hazards regression was used to estimate the HR for dairy fat intake and T2D risk.

RESULTS

During 4,219,457 person-years of follow-up, we documented 16,511 incident T2D cases. Dairy fat was not associated with risk of T2D when compared with calories from carbohydrates (HR for extreme quintiles: 0.98; 95% CI: 0.95, 1.02). Replacing 5% of calories from dairy fat with other sources of animal fat or carbohydrate from refined grains was associated with a 17% (HR: 1.17; 95% CI: 1.13, 1.21) and a 4% (HR: 1.04; 95% CI: 1.00, 1.08) higher risk of T2D, respectively. Conversely, a 5% calorie replacement with carbohydrate from whole grains was associated with a 7% lower risk of T2D (HR: 0.93; 95% CI: 0.88, 0.98).

CONCLUSIONS

Dairy fat intake was not associated with T2D risk in these cohort studies of US men and women when compared with calories from carbohydrate. Replacing dairy fat with carbohydrates from whole grains was associated with lower risk of T2D. Replacement with other animal fats or refined carbohydrates was associated with higher risk.

Genetic Evidence That Carbohydrate-Stimulated Insulin Secretion Leads to Obesity

BACKGROUND

A fundamental precept of the carbohydrate-insulin model of obesity is that insulin secretion drives weight gain. However, fasting hyperinsulinemia can also be driven by obesity-induced insulin resistance. We used genetic variation to isolate and estimate the potentially causal effect of insulin secretion on body weight.

METHODS

Genetic instruments of variation of insulin secretion [assessed as insulin concentration 30 min after oral glucose (insulin-30)] were used to estimate the causal relationship between increased insulin secretion and body mass index (BMI), using bidirectional Mendelian randomization analysis of genome-wide association studies. Data sources included summary results from the largest published metaanalyses of predominantly European ancestry for insulin secretion (n = 26037) and BMI (n = 322154), as well as individual-level data from the UK Biobank (n = 138541). Data from the Cardiology and Metabolic Patient Cohort study at Massachusetts General Hospital (n = 1675) were used to validate genetic associations with insulin secretion and to test the observational association of insulin secretion and BMI.

RESULTS

Higher genetically determined insulin-30 was strongly associated with higher BMI (β = 0.098, P = 2.2 × 10^-21), consistent with a causal role in obesity. Similar positive associations were noted in sensitivity analyses using other genetic variants as instrumental variables. By contrast, higher genetically determined BMI was not associated with insulin-30.

CONCLUSIONS

Mendelian randomization analyses provide evidence for a causal relationship of glucose-stimulated insulin secretion on body weight, consistent with the carbohydrate-insulin model of obesity.

Dietary Glycemic Index and Load and the Risk of Type 2 Diabetes: Assessment of Causal Relations

While dietary factors are important modifiable risk factors for type 2 diabetes (T2D), the causal role of carbohydrate quality in nutrition remains controversial. Dietary glycemic index (GI) and glycemic load (GL) have been examined in relation to the risk of T2D in multiple prospective cohort studies. Previous meta-analyses indicate significant relations but consideration of causality has been minimal. Here, the results of our recent meta-analyses of prospective cohort studies of 4 to 26-y follow-up are interpreted in the context of the nine Bradford-Hill criteria for causality, that is: (1) Strength of Association, (2) Consistency, (3) Specificity, (4) Temporality, (5) Biological Gradient, (6) Plausibility, (7) Experimental evidence, (8) Analogy, and (9) Coherence. These criteria necessitated referral to a body of literature wider than prospective cohort studies alone, especially in criteria 6 to 9. In this analysis, all nine of the Hill's criteria were met for GI and GL indicating that we can be confident of a role for GI and GL as causal factors contributing to incident T2D. In addition, neither dietary fiber nor cereal fiber nor wholegrain were found to be reliable or effective surrogate measures of GI or GL. Finally, our cost-benefit analysis suggests food and nutrition advice favors lower GI or GL and would produce significant potential cost savings in national healthcare budgets. The high confidence in causal associations for incident T2D is sufficient to consider inclusion of GI and GL in food and nutrient-based recommendations.

Associations among tourist camp management, high and low tourist seasons, and welfare factors in female Asian elephants in Thailand

This study investigated how camp management and tourist activities affect body condition, adrenocortical function, lipid profiles and metabolic status in female tourist elephants. We compared twice monthly serum insulin, glucose, fructosamine, total cholesterol (TC), triglyceride (TG), low density lipoprotein (LDL), high density lipoprotein (HDL), and fecal glucocorticoid metabolite (FGM) concentrations to body condition scores (BCS) at five camps with different management styles (e.g., tourist activities, work type, diet) between the High (November–February) and Low (March–October) tourist seasons. There were significant camp effects on health parameters, with BCS, TC, HDL, insulin and glucose being among the highest, and G:I being the lowest (less heathy) in elephants at an observation camp compared to those at camps where elephants received exercise by providing rides to tourists. Differences between High and Low tourist season months also were found for all measures, except TG and FGM concentrations. Both work time and walking distance were negatively correlated to glucose, fructosamine and insulin, while walking distance was negatively related to FGM concentrations. By contrast, positive associations were found between tourist number and BCS, TG, and insulin, perhaps related to tourists feeding elephants. Quantity of supplementary diet items (e.g., bananas, sugar cane, pumpkin) were positively correlated with FGM concentrations, glucose, fructosamine, and insulin. This study provides evidence that body condition, adrenal activity, metabolic markers, and lipid profiles in captive elephants may be affected by visitor numbers, work activities, and the amount of supplementary foods offered by tourists. Some activities appear to have negative (e.g., feeding), while others (e.g., exercise) may have positive effects on health and welfare. We conclude that camps adopting a more hands-off approach to tourism need to ensure elephants remain healthy by providing environments that encourage activity and rely on more natural diets or foraging.

Low-Carb and Ketogenic Diets in Type 1 and Type 2 Diabetes

Low-carb and ketogenic diets are popular among clinicians and patients, but the appropriateness of reducing carbohydrates intake in obese patients and in patients with diabetes is still debated. Studies in the literature are indeed controversial, possibly because these diets are generally poorly defined; this, together with the intrinsic complexity of dietary interventions, makes it difficult to compare results from different studies. Despite the evidence that reducing carbohydrates intake lowers body weight and, in patients with type 2 diabetes, improves glucose control, few data are available about sustainability, safety and efficacy in the long-term. In this review we explored the possible role of low-carb and ketogenic diets in the pathogenesis and management of type 2 diabetes and obesity. Furthermore, we also reviewed evidence of carbohydrates restriction in both pathogenesis of type 1 diabetes, through gut microbiota modification, and treatment of type 1 diabetes, addressing the legitimate concerns about the use of such diets in patients who are ketosis-prone and often have not completed their growth.

Vitamin D restriction enhances periovarian adipose tissue inflammation in a model of menopause

Background: Menopause and deficiency in vitamin D (VD) are two health problems usually associated with aging women.Objective: We aimed to study inflammation in visceral adipose tissue when bilateral ovariectomy is combined with dietary restriction in VD.Methods: We studied 60 female C57BL/6 mice 3 months of age. Half of the animals had bilateral ovariectomy (Ovx group, n = 30) and half a sham procedure (Control [C] group, n = 30), and half of each Ovx or C group were fed a standard diet containing VD or a diet restricted in VD (D-) for an additional 12 weeks. Therefore, four groups were formed (n = 15 each group): C, C(D-), Ovx, and Ovx(D-). After sacrifice, the periovarian adipose tissue (PAT) was investigated.Results: In PAT, we observed different levels of hypertrophied adipocytes, enhanced proinflammatory cytokines, activation of inflammatory markers, and components of the extracellular signal-regulated kinase. The most affected PAT was seen in the Ovx(D-) group, followed by the Ovx group, the C(D-) group, and the C group (the least altered).Conclusion: The results demonstrate that ovariectomy and dietary restriction of VD are inducers of adverse effects on mouse visceral adipose tissue. When combined, these insults might enhance PAT inflammation.

The Metabolomic Signatures of Weight Change

Obesity represents a major health concern, not just in the West but increasingly in low and middle income countries. In order to develop successful strategies for losing weight, it is essential to understand the molecular pathogenesis of weight change. A number of pathways, implicating oxidative stress but also the fundamental regulatory of insulin, have been implicated in weight gain and in the regulation of energy expenditure. In addition, a considerable body of work has highlighted the role of metabolites generated by the gut microbiome, in particular short chain fatty acids, in both processes. The current review provides a brief understanding of the mechanisms underlying the associations of weight change with changes in lipid and amino acid metabolism, energy metabolism, dietary composition and insulin dynamics, as well as the influence of the gut microbiome. The changes in metabolomic profiles and the models outlined can be used as an accurate predictor for obesity and obesity related disorders.

The rationale and design of the personal diet study, a randomized clinical trial evaluating a personalized approach to weight loss in individuals with pre-diabetes and early-stage type 2 diabetes

Weight loss reduces the risk of type 2 diabetes mellitus (T2D) in overweight and obese individuals. Although the physiological response to food varies among individuals, standard dietary interventions use a "one-size-fits-all" approach. The Personal Diet Study aims to evaluate two dietary interventions targeting weight loss in people with prediabetes and T2D: (1) a low-fat diet, and (2) a personalized diet using a machine-learning algorithm that predicts glycemic response to meals. Changes in body weight, body composition, and resting energy expenditure will be compared over a 6-month intervention period and a subsequent 6-month observation period intended to assess maintenance effects. The behavioral intervention is delivered via mobile health technology using the Social Cognitive Theory. Here, we describe the design, interventions, and methods used.

Beneficial effects of intermittent fasting on steatosis and inflammation of the liver in mice fed a high-fat or a high-fructose diet

OBJECTIVE

Intermittent fasting (IF) is a nutritional intervention with significant metabolic effects on the liver that are not yet fully understood. The aim of this study was to investigate the effects of IF on body mass, lipid profile, glucose metabolism, liver lipogenesis, β-oxidation, and inflammation.

METHODS

We used cellular and molecular techniques to investigate the effects of IF on 3-mo-old male C57 BL/6 mice that were fed control (10% kcal fat), high-fat (HF; 50% kcal fat), or high-fructose (HFr; 50% kcal fructose) diets for 8 wk. Half of the animals were submitted to IF (1 d fed, 1 d fast) for an additional 4 wk.

RESULTS

Although food intake on the fed day did not differ between the groups, mice in the HF and HFr groups showed diminished body mass, total cholesterol, and triacylglycerol levels. Also, plasma adiponectin increased in the HFr group and leptin decreased in the HF mice. Oral glucose tolerance test and insulin were ameliorated by IF, regardless of the diet consumed (HF or HFr), and decreased hepatic lipogenesis and increased β-oxidation markers, resulting in a reduction of the hepatic steatosis and inflammation.

CONCLUSIONS

There were beneficial effects of IF even with the continuity of the obesogenic diet and proinflammatory diet in mice. It is recommended that based on the beneficial effects of IF on glucose and liver metabolism and inflammation that IF be a coadjutant factor in the treatment of hepatic metabolic issues and steatosis.