Weight loss with very-low-calorie diet and cardiovascular risk factors in moderately obese women: one-year follow-up study including ambulatory blood pressure monitoring

Short- and long-term effects of very low- and low-calorie ketogenic diets on metabolism and cardiometabolic risk factors: a narrative review

Worldwide obesity and cardiovascular diseases have encouraged the adoption of new and efficient dietary strategies. Among various proposed diets, ketogenic diets, both the very-low-calorie ketogenic diet (VLCKD) and the low-calorie ketogenic diet (LCKD), have been suggested in recent years as an effective nutritional approach for obesity management. The VLCKD and the LCKD are characterized by a low carbohydrate content (<50 g/day), 1-1.5 g of protein/kg of ideal body weight, less than 20-30 g of lipids, and a daily intake of about 800 calories for VLCKD and about 1200-1400 calories for LCKD. The purpose of our narrative review is to offer an overview of the most impactful studies in the scientific literature regarding VLCKD and LCKD to discuss their short- and long-term effects (less than 12 months and more than 12 months respectively) on weight loss, metabolic and cardiovascular aspects. Articles we focused on were cohort studies, case-control studies, cross-sectional studies, randomized controlled trials, and meta-analyses. Results indicate that VLCKD and LCKD could be helpful to ameliorate metabolic and cardiovascular risk factors such as weight loss, glucose, and cholesterol levels, both in the short and long term. Further research in this area may include more randomized controlled trials to gather more data.

Effect of weight loss on blood pressure changes in overweight patients: A systematic review and meta-analysis

To determine quantitative differences between weight loss and changes in clinic blood pressure (BP) and ambulatory BP in patients with obesity or overweight, the authors performed a meta-analysis. PubMed, Embase, and Scopus databases were searched up to June 2022. Studies that compared clinic or ambulatory BP with weight loss were included. A random effect model was applied to pool the differences between clinic BP and ambulatory BP. Thirty-five studies, for a total of 3219 patients were included in this meta-analysis. The clinic systolic blood pressure (SBP) and diastolic blood pressure (DBP) were significantly reduced by 5.79 mmHg (95% CI, 3.54-8.05) and 3.36 mmHg (95% CI, 1.93-4.75) after a mean body mass index (BMI) reduction of 2.27 kg/m² , and the SBP and DBP were significantly reduced by 6.65 mmHg (95% CI, 5.16-8.14) and 3.63 mmHg (95% CI, 2.03-5.24) after a mean BMI reduction of 4.12 kg/m² . The BP reductions were much larger in patients with a BMI decrease ≥3 kg/m² than in patients with less BMI decrease, both for clinic SBP [8.54 mmHg (95% CI, 4.62-12.47)] versus [3.83 mmHg (95% CI, 1.22-6.45)] and clinic DBP [3.45 mmHg (95% CI, 1.59-5.30)] versus [3.15 mmHg (95% CI, 1.21-5.10)]. The significant reduction of the clinic and ambulatory BP followed the weight loss, and this phenomenon could be more notable after medical intervention and a larger weight loss.

Diet Quality following Total Meal Replacement Compared with Food-Based Weight-Loss Diets in Postmenopausal Women with Obesity: A Secondary Analysis of the TEMPO Diet Trial

BACKGROUND

Severely energy-restricted diets that utilize meal-replacement products are the most effective dietary treatment for obesity. However, there are concerns they may fail to educate individuals on how to adopt a healthy food-based diet after weight loss.

OBJECTIVES

The aim of this research was to compare changes in diet quality following total meal replacement compared with food-based weight-loss diets.

METHODS

In this secondary analysis of a randomized controlled trial, 79 postmenopausal women aged 45-65 y, with a BMI (in kg/m2) of 30-40, were randomly assigned to either a total meal-replacement diet (energy intake restricted by 65-75% relative to requirements) for 16 wks, followed by a food-based diet (energy intake restricted by 25-35% relative to requirements) until 52 wks, or the food-based diet for the entire 52-wk period. Diet quality was scored at baseline and 52 wks using the Healthy Eating Index for Australian Adults, with score changes compared between groups using an independent t test.

RESULTS

Diet quality improved from baseline in both groups, but less so in the total meal-replacement group, with a mean (SD) increase of 3.6 (10.8) points compared with 11.8 (13.9) points in the food-based group, resulting in a mean between-group difference of -8.2 (P = 0.004; 95% CI: -13.8, -2.7) points. This improvement in diet quality within both groups was mostly driven by a reduction in the intake of discretionary foods. Intake remained below the recommendations at 52 wks for 4 of the 5 food groups in both dietary interventions.

CONCLUSIONS

In postmenopausal women with obesity, weight-loss interventions that involve either a total meal-replacement diet or a food-based diet both improve diet quality, however, not sufficiently to meet recommendations. This highlights the importance of addressing diet quality as a part of all dietary weight-loss interventions. This trial is registered with the Australia and New Zealand Clinical Trials Registry as 12612000651886.

The longer-term effects of Roux-en-Y gastric bypass surgery on sodium excretion

BACKGROUND

Obesity is an independent risk factor for hypertension and chronic kidney disease. During the first months after bariatric surgery, an improvement of sodium excretion has been described. The aim of this work was to study the influence of bariatric surgery on sodium excretion at more than a year after the intervention.

METHODS

Patients who have undergone Roux-en-Y gastric bypass (RYGB) and who had collected a 24-h urine sample before surgery more than 12 months ago were asked to participate. A second 24-h urine sample was collected. Blood pressure and weight were measured. The difference in sodium excretion before and after surgery was calculated, and the relationship with blood pressure and weight loss was investigated.

RESULTS

We included 33 patients; the median follow-up time was 21 months (range 14-41). Sodium excretion was high before surgery (median 195 mmol/day, IQR range 167-247) and decreased by 18 % after surgery (median 160 mmol/day, IQR range 118-205, p = 0.015), while there were significant improvements in body weight (% EWL 80.9 ± 21.8), systolic blood pressure (126 to 120 mmHg, p = 0.02), and diastolic blood pressure (84 to 77 mmHg, p = 0.002), even with a reduced number of antihypertensive drugs.

CONCLUSIONS

After RYGB and considerable weight loss, sodium excretion remains high in the longer term. The profound improvement in blood pressure cannot be explained by reductions in sodium excretion after RYGB.

Childhood obesity for pediatric gastroenterologists

Obesity in childhood is one of the major health issues in pediatric health care today. As expected, the prevalence of obesity-related comorbidities has risen in parallel with that of obesity. Consultation regarding these concomitant diseases and subsequent management by subspecialists, including pediatric gastroenterologists, is now common and has resulted in obesity being recognized as a chronic disease requiring coordination of care. Although medications and even surgery may provide effective, though often temporary, treatments for obesity and its comorbidities, behavioral interventions addressing healthy dietary and physical activity habits remain a mainstay in the obesity treatment paradigm. Therefore, the issue of weight management must be addressed by both general practitioner and subspecialist alike. In this report, we review select aspects of pediatric obesity and obesity-related management issues because it relates in particular to the field of pediatric gastroenterology and hepatology.

Favorable changes in lipid profile: the effects of fasting after Ramadan

Aims

We assessed the effect of fasting during Ramadan on blood pressure (BP), body weight, plasma lipid, and lipoprotein variables among healthy normal individuals.

Methods

102 (68% male) multi-ethnic volunteers; mean age ± SD (38.7±10.5 years) were randomly recruited in Al-Ain, United Arab Emirates (UAE), to be investigated before Ramadan, one day after the end of Ramadan, and four weeks after Ramadan. Anthropometric, demographic, fasting plasma total cholesterol (TC), triglyceride (TG), and high density lipoprotein–cholesterol (HDL-C) were measured by standard methods, and Low density lipoprotein-cholesterol (LDL-C) was calculated using Friedewald’s formula.

Results

65 subjects completed the study. We found significant and beneficial changes in systolic blood pressure (SBP), body weight, waist circumference (WC), TG, HDL-C and LDL-C, at the end of Ramadan, but not in TC. Further, there was a progressive and significant increase and decrease in HDL-C and LDL-C levels, respectively, four weeks after Ramadan.

Conclusions

We observed significant improvements in HDL-C, and LDL-C levels even after four weeks post Ramadan. Ramadan-like fasting may be considered for more effective lipid and lipoprotein control.

The Effects of Very-Low-Calorie Diets on HDL: A Review

This paper investigates the effects of very-low-calorie diets (VLCDs) used in the treatment of obesity on high-density lipoprotein (HDL) levels. Although the studies varied widely in their intervention format, duration, and baseline HDL levels, it would appear that HDL levels usually decrease during active weight loss using a VLCD, but these either return to pre-VLCD levels or improve overall during the weight-maintenance phase. More research needs to be done to determine optimal weight-maintenance programmes and the effects of VLCDs in the short term as well as on HDL levels in groups at increased risk of coronary heart disease.

Skeletal muscle structural lipids improve during weight-maintenance after a very low calorie dietary intervention

Background

The objective was to investigate in a group of obese subjects the course in skeletal muscle phospholipid (SMPL) fatty acids (FA) during a 24-weeks weight maintenance program, which was preceded by a successful very low calorie dietary intervention (VLCD). Special focus was addressed to SMPL omega-3 FA, which is a lipid entity that influences insulin action.

Methods

Nine obese subjects (BMI = 35.7 ± 1.0 kg/m²), who had completed an 8 weeks VLCD (weight-loss = -9.7 ± 1.6 kg, P < 0.001), had obtained skeletal muscle biopsies (vastus lateralis) before and after a dietician-guided 24-weeks weight-maintenance program (-1.2 ± 1.5 kg, P = ns). SMPL FA composition was determined by gas liquid chromatography. During the preceding VLCD, insulin sensitivity (HOMA-IR) and glycemic control (HbA1c) improved but no change in SMPL omega-3 FA was observed. During the weight-maintenance program five subjects received the pancreas lipase inhibitor Orlistat 120 mg t.i.d. versus placebo.

Results

HOMA-IR and HbA1c stabilized and SMPL total omega-3 FA, docosahexaenoic acid and ratio of n-3/n-6 polyunsaturated FA increased by 24% (P < 0.01), 35% (P < 0.02) and 26% (P < 0.01), respectively, whereas saturated and monounsaturated FA did not change. Plasma total-cholesterol and LDL-cholesterol, which decreased during the VLCD, reverted to pre-VLCD levels (P < 0.01). Orlistat therapy was associated with weight-loss (P < 0.05), trends for better glycemic control (P = 0.15) and greater increase in SMPL docosahexaenoic acid (P = 0.12) but similar reversal of plasma cholesterols compared to placebo.

Conclusion

The data are consistent with the notion that greater SMPL omega-3 FA obtained during a weight-maintenance program may play a role for preserving insulin sensitivity and glycemic control being generated during a preceding VLCD.

Desaturation of skeletal muscle structural and depot lipids in obese individuals during a very-low-calorie diet intervention

OBJECTIVE

This study investigated whether a very-lowcalorie dietary intervention (VLCD) may influence composition of skeletal muscle cell membrane phospholipid and composition and concentration of intramyocellular triglyceride (IMTG) in obese subjects. The working hypothesis proposed that a VLCD would decrease saturated fatty acids (FAs) and increase long-chain polyunsaturated FAs (LCPUFAs) in muscular structural lipids, as such changes have been associated with improved insulin sensitivity.

RESEARCH METHODS AND PROCEDURES

Skeletal muscle biopsies (vastus lateralis) were obtained from 13 obese subjects (nine women) before and after 8 weeks on VLCD (approximately 600 to 800 kcal/d). FA composition in muscle cell membrane phospholipid and concentration and FA composition of IMTG were determined by gas-liquid chromatography.

RESULTS

Baseline BMI was 36.0 +/- 3.4 kg/m2. Weight loss was 9.3 +/- 1.1 kg (8.8 +/- 1.1%; p < 0.0001); loss of adipose tissue was 5.9 +/- 0.9 kg (p < 0.0001). Insulin resistance (by homeostasis model assessment) decreased (-44 +/- 7%; p < 0.001). Muscle cell membrane phospholipid saturated FAs decreased (-3.2 +/- 1.3%; p < 0.05), whereas monounsaturated FAs (4.3 +/- 1.7%; p < 0.05), LCPUFAs (11 +/- 6%; p < 0.05), and the ratio of LCPUFAs to saturated FAs (12 +/- 5%; p < 0.05) increased. IMTG decreased, but not significantly (-5%). IMTG-saturated FAs decreased (-3.3 +/- 1.5%; p < 0.05), whereas LCPUFAn-3 (29 +/- 9%; p < 0.01), LCPUFAn-6 (33 +/- 9%; p < 0.01), and the ratio of LCPUFAs to saturated FAs (34 +/- 8%; p < 0.001) increased. Plasma total cholesterol (-15 +/- 6%; p < 0.05), low-density lipoprotein-cholesterol (-16 +/- 5%; p < 0.01), high-density lipoprotein-cholesterol (-8 +/- 2%; p < 0.01), and plasma triglyceride (-19 +/- 12%; p = 0.10) all decreased during the VLCD.

DISCUSSION

Desaturation of both muscle cell membrane phospholipid and IMTG was significant but modest during a VLCD in obese subjects. Further research must delineate whether such changes in skeletal muscle structural and depot lipid composition themselves are enough to promote the observed improvements in insulin action.

Weight Loss and Lipid Changes with Low-Energy Diets: Comparator Study of Milk-Based versus Soy-Based Liquid Meal Replacement Interventions

OBJECTIVES

Soy protein intake has favorable effects on body weight and fat distribution in experimental animals but these effects have not been demonstrated in humans. To compare effects of soy- vs. milk-based meal replacements (MR) we assessed weight loss and serum lipoproteins changes for obese subjects who consumed low-energy diets (LED) including either milk-based or soy-based MR.

METHODS

Overweight or obese women and men (body mass indices 27-40 kg/m(2)) were randomly assigned to LED providing 1200 kcal/day, with consumption of five soy-based or two milk-based liquid MR for a 12-week weight loss trial. Serum lipoprotein measurements were obtained at baseline, 6 and 12 weeks.

RESULTS

For soy and milk MR groups, subject numbers were, respectively, 51 and 39 randomized and 30 and 22 completers. MR use averaged: soy, 3.7/day; and milk, 1.9/day. Weight losses for completers at 12 weeks were: soy MR, 9.0% of initial body weight (95% confidence intervals, 7.3-10.6%); and milk MR, 7.9% (5.8-8.8%) with no significant differences. Reductions from baseline in serum cholesterol and LDL-cholesterol values, respectively, at six weeks were significantly greater (P < 0.015) with soy MR (15.2% and 17.4%) than with milk MR (7.9% and 7.7%). Soy MR use was associated with significant reductions in serum triglycerides at 6 and 12 weeks while milk MR use was not.

CONCLUSIONS

Soy MR use, as part of a low-energy diet, was associated with slightly but not significantly greater weight loss over a 12-week period than milk MR use. These observations confirm previous studies documenting the effectiveness of MR use for weight loss.

Estudio del metabolismo hidrocarbonado en pacientes con obesidad mórbida: influencia de la pérdida de peso

OBJECTIVE

Examination of carbohydrate metabolism derangements in patients with morbid obesity and the influence of weight reduction through nutritional intervention. Assessment of gender influence on carbohydrate metabolism derangements and on response to diet.

PATIENTS AND METHOD

59 patients with morbid obesity were studied with anthropometric assessment and with carbohydrate metabolism assessment through an oral glucose overload and measurement of insulin resistance, before and after a dietary intervention alternating diets of very low caloric content with conventional low-calorie diets.

RESULTS

A very significant global weight reduction in both sexes was observed (95% confidence interval [CI], 26.9 to 39.8 kg in males, and 13.5 to 20.3 kg in women). A significant improvement in basal blood glucose was found in both sexes (95% CI: males, 0.44 to 46.5 mg/dl; women, 9.5 to 32.8 mg/dl), and in 120 minute oral glucose tolerance test (OGTT) blood glucose in women (95% CI: 3.5 to 52.9 mg/dl). Both males and women showed significant improvement in basal insulinemia (95% CI: males, 1.6 to 14.2 microU/ml; women, 3.9 to 8.5 microU/ml) and in sex hormone-binding globulins (SHBG) (95% CI: males, -30.1 to -13.3 nmol/l; women, -54 to -19.4 nmol/l). Both males and women showed an improvement of sensitivity to insulin measured with HOMA (HOMAIR) (95% CI: males, 1.46 to 3.59; women, 0.67 to 2.24).

CONCLUSION

In patients with morbid obesity carbohydrate metabolism derangements are common. Weight reduction led to a significant reduction of these derangements.

Structured weight-loss programs: meta-analysis of weight loss at 24 weeks and assessment of effects of intervention intensity

Obesity is increasing in epidemic proportions globally while current therapies continue to be suboptimal. In this investigation, weight loss in obese individuals after 24 weeks with different nutrition interventions was compared. The impact of intervention intensity was assessed. Inclusion criteria were established and a comprehensive literature review was performed. These nutrition interventions were identified and analyzable: meal replacements (MRs); energy-restricted (>1500 kcal/d) diets (ERDs); low-energy (800-1500 kcal/d) diets (LEDs); soy very low energy (<800 kcal/d) diets (VLEDs) referred to as SOYs; and VLEDs. Intensity was assessed using the following parameters: physician visits, clinic visits, and hours of class over 24 weeks; an intensity score represents an adjusted sum of the values. Weight losses at 24 weeks as percentage of baseline weights (95%, confidence intervals) were as follows: MRs, 9.1% (5.7-12.5); ERDs, 8.5% (4.9-12.1); LEDs, 11.4% (8.9-13.1); SOYs, 16.5% (13.9-19.1); and VLEDs, 21.3% (20.1-22.5). Weight loss with SOYs was significantly greater than with MRs and ERDs; weight loss with VLEDs was significantly greater than with any other diet. Energy intake was the most significant (P<.0001) regression variable related to weight loss; however, the intensity of intervention (P=.0003) was significantly stronger than initial body weight or duration of treatment. Medically supervised VLEDs are the most effective intervention for facilitating substantial weight loss over 24 weeks. SOY may promote more rapid weight loss over the first 8 weeks than other interventions. MRs appear to be equally effective with ERDs and LEDs with lower levels of intervention intensity.

Weight loss and weight maintenance, ambulatory blood pressure and cardiac autonomic tone in obese persons with the metabolic syndrome

BACKGROUND

Cardiac autonomic function may play a role in obesity-associated hypertension. Most studies on the effects of weight loss on blood pressure and autonomic function do not distinguish between acute or continuing weight loss and steady-state weight maintenance after weight loss.

OBJECTIVES

We sought to clarify the changes in ambulatory blood pressure, heart rate and heart rate variability as assessed by spectral analysis during rapid weight loss and extended weight maintenance.

PARTICIPANTS

Abdominally obese (body mass index 35.2 +/- 2.1 kg/m2, waist 114.3 +/- 9.0 cm) men and women (n = 41) with the metabolic syndrome.

METHODS AND RESULTS

The 34 men and women completing the 1-year weight maintenance period lost 14.6 +/- 3.5 kg during the 9-week very-low-calorie diet and maintained a 12.5 +/- 7.5 kg weight loss to the end of the trial. Ambulatory 24-h blood pressure decreased dramatically during the diet (-9.0 +/- 8.0/-4.6 +/- 4.9 mmHg), but had risen to near baseline levels by the end of weight maintenance (-2.2 +/- 8.2 /-1.2 +/- 6.1 mmHg). Night-time heart rate decreased (-5.5 +/- 9.6 beats/min, P = 0.012), and heart rate variability total and low-frequency power measured during 5 min of controlled breathing increased by 46-56% (P = 0.003-0.09) during rapid weight loss. These changes gradually attenuated during weight maintenance, and only the change in night-time heart rate was still of borderline significance after 1 year of weight maintenance (-3.6 +/- 8.6 beats/min, P = 0.063). Heart rate variability high-frequency power tended to increase during weight loss and weight maintenance.

CONCLUSION

Despite successful weight maintenance, the decrease in ambulatory blood pressure after rapid weight loss was largely transient. The increase in parasympathetic tone was more sustained, but also gradually attenuated during 1 year of weight maintenance.

[Cardiovascular risk factors in patients with morbid obesity: weight loss influence]

BACKGROUND

We studied the presence of cardiovascular risk factors in patients with morbid obesity and analyzed the influence of weight loss achieved through diet on these factors. We also evaluated the influence of gender on the presence of cardiovascular risk factors and on its response to diet.

PATIENTS AND METHODS

An anthropometric evaluation was performed in patients with morbid obesity (23 men and 36 women). The presence of cardiovascular risk factors was evaluated (fibrinogen, blood pressure, glucose metabolism determination by means of oral glucose tolerance test, complete lipid profile, sleep apnea syndrome), before and after following, on an alternative fashion, very-low calorie and low-calorie diets. The comparison was made with the t-test for paired samples.

RESULTS

A very significant weight loss was achieved in our patients, particularly in men (decrease of 33.4 kg, 95% CI: 26.9 to 39.8). This was accompanied by a reduction in the presence of cardiovascular risk factors, particularly in men, in whom the body fat distribution improved significantly (decrease in waist: 24.8 cm, 95% CI 18.4 to 36.5), as well as the lipid profile including triglycerides, VLDLc, HDLc and B100 apoprotein.

CONCLUSIONS

Patients with morbid obesity have a high prevalence of cardiovascular risk factors. A significant reduction of this prevalence can be achieved with diet during one year. This improvement is particularly significant in men.

Metabolic characteristics and body composition in a model of anti-obese rats (Lou/C)

OBJECTIVE

The aims of this study were to investigate some features of the metabolic profile and the body composition of male Lou/C rats and to examine whether these characteristics are strictly related to the food-intake reduction.

RESEARCH METHODS AND PROCEDURES

Fourteen-week-old male Lou/C rats were compared with age-matched male Wistar rats fed ad libitum (WAL) and another group of male Wistar rats whose food was chronically restricted (WFR) to the same amount as the Lou/C rats from weeks 3 to 14.

RESULTS

Food intake and body weight were significantly (p < 0.01) reduced in Lou/C compared with WAL rats, whereas these reductions were perfectly reproduced in WFR rats. Lou/C rats demonstrated lower relative weights of retroperitoneal (0.97 +/- 0.07 vs. 1.67 +/- 0.16 and 1.88 +/- 0.15 g/100 g body) and epididymal (1.01 +/- 0.02 vs. 1.62 +/- 0.12 and 1.80 +/- 0.11 g/100g body) fat depots than did the two other groups and no decrease in the percentage of carcass proteins, which was observed in the WFR rats. In addition, compared with the WFR group, the Lou/C rats showed lower plasma glucose levels (3.65 +/- 0.14 vs. 4.72 +/- 0.15 and 4.7 +/- 0.19 mM); a tendency (p < 0.1) for lower liver glycogen concentrations; and similar levels of glycerol, free fatty acids, and beta-hydroxybutyrate concentrations. Epinephrine and the relative weight of the adrenal glands were significantly (p < 0.01) lower in the Lou/C rats than in the WAL rats and the two other groups, respectively.

DISCUSSION

The ability of the Lou/C rats to accumulate less body fat than their equally food-restricted Wistar counterparts (WFR) suggests a difference in basal metabolism in this strain of rats that resembles obesity-resistant rats.

Very low energy diets in the treatment of obesity

Very low energy diets (VLEDs) are defined as diets which contain energy levels of less than 3.4 MJ (800 kcal) per day and contain daily allowances of all essential nutritional requirements. These diets have been in clinical use for more than 20 years. They are used as the only source of nutrition for 8-16 weeks, which usually achieves a weight loss of 1.5-2.5 kg per week. Before using this type of diet a medical investigation is necessary to evaluate contraindications and to check medication use during the diet. To facilitate maintenance, cognitive behavioural counselling should always be included in a weight reduction programme using a very low energy diet. VLEDs have no serious harmful effects and can safely be used in patients with various chronic diseases. Programmes using VLEDs produce better short-term weight loss than programmes without the diet. However, in randomized controlled trials VLED-based programmes have not achieved significantly better long-term maintenance than conventional programmes. VLEDs are used when rapid weight loss is necessary because of an obesity-related disease. In other patients with obesity it is an alternative to other conservative approaches for treatment of obesity. In type 2 diabetes it may improve long-term glucose metabolism better than conventional weight reducing diets. Some studies suggest that after a VLED-based programme long-term maintenance is better among men than women. This possible gender difference is an important topic for further research.