Effects of Consuming Preloads with Different Energy Density and Taste Quality on Energy Intake and Postprandial Blood Glucose

The significance and potential of functional food ingredients for control appetite and food intake

Dramatically rising global levels of obesity have raised consumers’ commercial and public health interest in foods that may help control appetite and weight. The satiety cascade consists of sensory, cognitive, physical, and hormonal events following food intake, preventing overeating, and the desire to eat for a long time. Functional foods can be one of the most influential factors in reducing appetite as long as effective ingredients, such as fiber and protein, are used to design these products. Also, functional foods should be designed to reduce appetite at different levels of oral processing, stomach, small intestine, and large intestine by various mechanisms. Therefore, the satiety power of functional foods depends on the type of ingredients and their amount. Because each compound has a different mechanism of action, it is recommended to use different compounds to influence satiety in functional foods.

Calorie reformulation: a systematic review and meta-analysis examining the effect of manipulating food energy density on daily energy intake

BACKGROUND

Dietary energy density is thought to be a contributor to obesity, but the extent to which different magnitudes and types of reductions to food energy density decreases daily energy intake is unclear. The primary objective was to systematically review and meta-analyse experimental studies that have examined the effect that manipulating energy density of food has on total daily energy intake. Secondary objectives were to examine moderators of the effect that altering energy density has on daily energy intake and effects on body weight.

METHODS

A systematic review and multi-level meta-analysis of studies on human participants that used an experimental design to manipulate the energy density of foods served and measured energy intake for a minimum of 1 day.

RESULTS

Thirty-one eligible studies sampling both children (n = 4) and adults (n = 27) contributed 90 effects comparing the effect of higher vs. lower energy density of served food on daily energy intake to the primary meta-analysis. Lower energy density of food was associated with a large decrease in daily energy intake (SMD = - 1.002 [95% CI: - 0.745 to - 1.266]). Findings were consistent across studies that did vs. did not manipulate macronutrient content to vary energy density. The relation between decreasing energy density and daily energy intake tended to be strong and linear, whereby compensation for decreases to energy density of foods (i.e. by eating more at other meals) was minimal. Meta-analysis of (n = 5) studies indicated that serving lower energy dense food tended to be associated with greater weight loss than serving higher energy dense food, but this difference was not significant (- 0.7 kg difference in weight change, 95% CIs: - 1.34, 0.04).

CONCLUSIONS

Decreasing the energy density of food can substantially reduce daily energy intake and may therefore be an effective public health approach to reducing population level energy intake.

TRIAL REGISTRATION

Registered on PROSPERO ( CRD42020223973 ).

Influence of Sensory Properties in Moderating Eating Behaviors and Food Intake

Sensory properties inform likes and dislikes, but also play an important functional role in guiding food choice and intake behavior. Odors direct food choice and stimulate sensory-specific appetites and taste helps to anticipate calorie and nutrient content of food. Food textures moderate eating rate and the energy consumed to satiation and post-ingestive metabolism. We summarize how sensory cues moderate intake, and highlight opportunities to apply sensory approaches to improve dietary behavior. Salt, sweet and savory taste influence liking, but also influence energy intake to fullness, with higher taste intensity and duration linked to lower intake. Psycho-physical studies show it is relatively easy to rank taste intensities at different concentrations but more challenging to discriminate fat contents, and fat discrimination declines further when combined with high-taste intensity. Fat has low impact on sensory intensity, but makes significant contributions to energy content. Combinations of high taste and fat-content can promote passive energy over-consumption, and adding fat also increases energy intake rate (kcals/min), reducing opportunities to orally meter consumption. Consumers adapt their oral processing behaviors to a foods texture, which can influence the rate and extent of energy intake. Understanding how texture influences eating behaviors and bolus formation, affords new opportunities to impact eating rate, energy intake and metabolic response to food. Food formulation has traditionally focused on composition and sensory appeal. Future research needs to consider the role of sensory properties in moderating consumer interaction with their food environment, and how they influence calorie selection, and shape our eating behaviors and intake.

Macronutrient Sensing in the Oral Cavity and Gastrointestinal Tract: Alimentary Tastes

There are numerous and diverse factors enabling the overconsumption of foods, with the sense of taste being one of these factors. There are four well established basic tastes: sweet, sour, salty, and bitter; all with perceptual independence, salience, and hedonic responses to encourage or discourage consumption. More recently, additional tastes have been added to the basic taste list including umami and fat, but they lack the perceptual independence and salience of the basics. There is also emerging evidence of taste responses to kokumi and carbohydrate. One interesting aspect is the link with the new and emerging tastes to macronutrients, with each macronutrient having two distinct perceptual qualities that, perhaps in combination, provide a holistic perception for each macronutrient: fat has fat taste and mouthfeel; protein has umami and kokumi; carbohydrate has sweet and carbohydrate tastes. These new tastes can be sensed in the oral cavity, but they have more influence post- than pre-ingestion. Umami, fat, kokumi, and carbohydrate tastes have been suggested as an independent category named alimentary. This narrative review will present and discuss evidence for macronutrient sensing throughout the alimentary canal and evidence of how each of the alimentary tastes may influence the consumption of foods.

Consumption of Foods With Higher Energy Intake Rates is Associated With Greater Energy Intake, Adiposity, and Cardiovascular Risk Factors in Adults

BACKGROUND

Both high energy density and fast eating rates contribute to excess energy intakes. The energy intake rate (EIR; kcal/min) combines both the energy density (kcal/g) and eating rate (g/min) of a food to quantify the typical rate at which calories of different foods are ingested.

OBJECTIVES

We describe the EIRs of diets in a multi-ethnic Asian population, and examine relationships between the consumption of high-EIR foods and total energy intake, body composition, and cardio-metabolic risk factors.

METHODS

Diet and lifestyle data from the Singapore Multi-Ethnic Cohort 2 (n = 7011; 21-75 y), were collected through interviewer-administrated questionnaires. The EIR for each of the 269 foods was calculated as the product of its eating rate and energy density. Multivariable models were used to examine associations between the relative consumption of foods with higher and lower EIRs and energy intake, body composition, and cardio-metabolic risks, after adjusting for age, sex, ethnicity, education level, physical activity, smoking status, and alcohol drinking status.

RESULTS

Individuals with higher daily energy intakes and with obesity consumed a significantly larger percentage of their energy from high-EIR foods, with a smaller relative intake of lower-EIR foods. Individuals with raised serum cholesterol also consumed a significantly higher proportion of high-EIR foods, whereas those without hypertension consumed a larger percentage of energy intake from low-EIR foods. Individuals classified as having a "very high" dietary EIR had a significantly 1.3 kg higher body weight (95% CI, 0.2-1.5; P = 0.013), 0.4 kg/m2 higher BMI (95% CI, 0.03-0.8; P = 0.037), and 1.2 cm larger waist circumference (95% CI, 0.2-2.2; P = 0.010), and were more likely to have abdominal overweight (OR, 1.3; 95% CI, 1.1-1.5; P < 0.001) than those with a "low" dietary EIR.

CONCLUSIONS

Comparing foods by their EIRs summarizes the combined impact of energy density and eating rate, and may identify foods and dietary patterns that are associated with obesogenic eating styles and higher diet-related cardiovascular disease risk in an Asian population.

Effects of Artificial Sweetener Consumption on Glucose Homeostasis and Its Association with Type 2 Diabetes and Obesity

Artificial sweeteners (ASs) are popular for their characteristic property of providing sweetness with few or no calories. They are frequently consumed to minimize energy intake and to combat obesity and its related adverse health effects. However, since their introduction, concerns have been raised regarding their safety. Extensive research has designed a number of studies to evaluate potential adverse effects, the top among them being interference with glucose homeostasis. Numerous studies have tried to prove that AS may contribute to the development of metabolic diseases including obesity and type 2 diabetes (T2D). The matter remains controversial and a favorite topic of research. The purpose of this review was to identify and discuss the published articles that have examined the effects of AS consumption on glucose homeostasis and its association with T2D and obesity. It was observed that studies have failed to present concrete evidence to establish a link between AS consumption and glucose homeostasis, obesity, or T2D. Most studies have flaws in the study design resulting in haphazard claims with no follow-up studies to confirm reliability. It is concluded that while it is not possible to claim that ASs are metabolically inert, at the moment the haphazard evidence is not enough to link their use with glucose metabolism, obesity or T2D. There is a need to design cohort and case-control studies with reliable sample sizes to establish a cause-effect relationship or to exclude claims of safety problems.

The effect of taste and taste perception on satiation/satiety: a review

As the prevalence of being overweight and obesity has increased worldwide, there is an increasing concern about satiation/satiety that can be achieved by eating. The ability of an individual to perceive tastes in the mouth is believed to be one of the many factors that influence food intake; the taste may affect appetite regulation and energy intake, playing an important role in promoting satiation/satiety. Satiation/satiety is actually induced by food and may be related to physiological and psychological factors such as several basic tastes, the exposure time of the taste and the cognition of different groups and individuals. This paper reviews the mechanism by which taste regulates satiation/satiety and demonstrates how taste and the taste perception of food prompt the brain to send satiation/satiety signals. Existing problems in taste and satiation/satiety and the prospective application of related research in the food industry are addressed, providing a scientific basis and theoretical guidance for the development and utilization of satiation/satiety from the perspective of taste.

Future foods: a manifesto for research priorities in structural design of foods

A number of major challenges facing modern society are related to the food supply. As the global population grows, it will be critical to feed everyone without damaging the environment. Advances in biotechnology, nanotechnology, structural design, and artificial intelligence are providing farmers and food manufacturers will new tools to address these problems. More and more people are migrating from rural to urban environments, leading to a change in their dietary habits, especially increasing consumption of animal-based products and highly-processed foods. Animal-based foods lead to more greenhouse gas production, land use, water use, and pollution than plant-based ones. Moreover, many animal-based and highly-processed foods have adverse effects on human health and wellbeing. Consumers are therefore being encouraged to consume more plant-based foods, such as fruits, vegetables, cereals, and legumes. Many people, however, do not have the time, money, or inclination to prepare foods from fresh produce. Consequently, there is a need for the food industry to create a new generation of processed foods that are desirable, tasty, inexpensive, and convenient, but that are also healthy and sustainable. This article highlights some of the main food-related challenges faced by modern society and how scientists are developing innovative technologies to address them.

Effect of Sequence of Fruit Intake in a Meal on Satiety

Little is known about the effects of manipulating sequence of fruit consumption during a meal in suppressing an individual’s appetite. Therefore, we investigate the effects of the sequence of fruit intake on satiety and blood glucose in a group of 17 healthy, young male adults. This intervention study repeatedly measured the effects of fruit intake (120 g red apple) before and after a meal and control (no fruit). Ad libitum test meal was weighed before and after a meal. Subjective appetite rating and appetite-related hormones were assessed at regular time intervals. The satiety score was significantly higher for fruit intake before a meal followed by after a meal and control (p < 0.05). Eating fruit before a meal reduced 18.5% (166 kcal) subsequent energy intake compared to control (p < 0.05). Fruit intake before a meal had a significantly higher incremental area under the curve (iAUC) of Glucagon-like peptide 1 (GLP-1), compared to after a meal (p < 0.05). There were no differences in plasma changes of ghrelin, Cholecystokinin 8 (CCK8), or blood glucose in all sessions. Consuming fruit before a meal potentially enhanced satiety. Further research is required to confirm both short- and long-term effects of the sequence of fruit intake on appetite regulation in a wider population.

The Metabolic Concept of Meal Sequence vs. Satiety: Glycemic and Oxidative Responses with Reference to Inflammation Risk, Protective Principles and Mediterranean Diet

With increasing exposure to eating opportunities and postprandial conditions becoming dominant states, acute effects of meals are garnering interest. In this narrative review, meal components, combinations and course sequence were questioned vis-à-vis resultant postprandial responses, including satiety, glycemic, oxidative and inflammatory risks/outcomes vs. protective principles, with reference to the Mediterranean diet. Representative scientific literature was reviewed and explained, and corresponding recommendations discussed and illustrated. Starting meals with foods, courses and/or preloads high in innate/added/incorporated water and/or fibre, followed by protein-based courses, delaying carbohydrates and fatty foods and minimizing highly-processed/sweetened hedonic foods, would increase satiety-per-calorie vs. obesogenic passive overconsumption. Similarly, starting with high-water/fibre dishes, followed by high-protein foods, oils/fats, and delayed/reduced slowly-digested whole/complex carbohydrate sources, optionally closing with simpler carbohydrates/sugars, would reduce glycaemic response. Likewise, starting with foods high in innate/added/incorporated water/fibre/antioxidants, high monounsaturated fatty acid foods/oils, light proteins and whole/complex carbohydrate foods, with foods/oils low in n-6 polyunsaturated fatty acids (PUFA) and n-6:n-3 PUFA ratios, and minimal-to-no red meat and highly/ultra-processed foods/lipids, would reduce oxidative/inflammatory response. Pyramids illustrating representative meal sequences, from most-to-least protective foods, visually communicate similarities between axes, suggesting potential unification for optimal meal sequence, consistent with anti-inflammatory nutrition and Mediterranean diet/meal principles, warranting application and outcome evaluation.

Unaware of the amount consumed: Systematic error in estimating food- and drink intake

BACKGROUND

Our current food environment promotes overconsumption due to the overrepresentation of foods that have a high calorie density and can be easily consumed. These food characteristics lead to limited oro-sensory exposure, which may lead to overconsumption due to insufficient perception of the amount consumed. Better perception of the amount eaten and thus a better ability to estimate intake may help control actual food intake through prolonged inter-meal interval and smaller meal sizes.

OBJECTIVE

The aim of this study was to determine whether food form, flavor and portion size influence the error in estimated intake (EiE).

METHOD

Participants (n = 72) were recruited at a science festival where the study was also performed. The experiment had a 2 × 2 × 3 design with a reference condition. Experimental conditions differed in food form (liquid vs. solid stimuli), taste category (savory vs. sweet) and portion size (small, medium, large). Water was used as a reference condition.

RESULTS

Participants overestimated the amount consumed of all stimuli. The overestimation was ten times greater for solid compared to liquid products (104 ± 12 vs 12 ± 9% overestimation) and was more pronounced for sweet (75 ± 9%) than for savory products (41 ± 12%). There was a trend for larger EiE% of smaller portions. No differences were found among the differently flavored liquids including the water reference.

CONCLUSION

People overestimate the amount they consume of solid and sweet products more than that of liquid and savory products. This overestimation may be due to overvaluation of the oro-sensory stimulation when visual cues and intake effort are controlled for or because of learned associations. However, the uncontrolled setting of the experiment should be taken into account when drawing conclusions. Future research may replicate the study in a more controlled setting and should determine whether the overestimation of sweet solid product intake also leads to lower intake at a subsequent meal.

A review of evidence supporting current strategies, challenges, and opportunities to reduce portion sizes

Although there is considerable evidence for the portion-size effect and its potential impact on health, much of this has not been successfully applied to help consumers reduce portion sizes. The objective of this review is to provide an update on the strength of evidence supporting strategies with potential to reduce portion sizes across individuals and eating contexts. Three levels of action are considered: food-level strategies (targeting commercial snack and meal portion sizes, packaging, food labels, tableware, and food sensory properties), individual-level strategies (targeting eating rate and bite size, portion norms, plate-cleaning tendencies, and cognitive processes), and population approaches (targeting the physical, social, and economic environment and health policy). Food- and individual-level strategies are associated with small to moderate effects; however, in isolation, none seem to have sufficient impact on food intake to reverse the portion-size effect and its consequences. Wider changes to the portion-size environment will be necessary to support individual- and food-level strategies leading to portion control.

Dietary energy density and appetite: A systematic review and meta-analysis of clinical trials

Studies have suggested that dietary energy density (DED) may affect weight gain by altering appetite. Although many studies have investigated the effect of DED on appetite, findings are inconsistent and, to our knowledge, there are no systematic reviews and meta-analyses on this topic. Therefore, the aim of this systematic review and meta-analysis was to summarize the effect of DED on appetite. The current meta-analysis revealed changing the DED had no significant effect on hunger but increased fullness. More high-quality randomized controlled trials are needed to investigate the effects of DED on appetite components. We searched titles, abstracts, and keywords of articles indexed in ScienceDirect, MEDLINE, and Google Scholar databases up to July 2018 to identify eligible RCT studies. Random effects model was used to estimate the pooled effect of DED on appetite. Among the 21 studies identified in the systematic literature search, 11 reports were included in the meta-analysis. Based on the Cochrane Collaboration Risk of Bias tool, 6 studies were considered as good quality, two were fair, and three studies were poor. The mean ± standard deviation for energy density, in studies which assessed fullness, was 1.65 ± 1 in high energy dense (HED) diet and 0.93 ± 0.93 in low energy dense (LED) diet. The corresponding values for hunger were 1.67 ± 0.69 and 0.70 ± 0.32, respectively. Compared with a LED diet, consumption of HED increased fullness (weighed mean difference [WMD] 2.95 mm; 95% CI 0.07-5.82, P = 0.044, I² 98.1%) but had no significant effect on hunger (WMD 1.31 mm; 95% CI -7.20 to 9.82, P = 0.763, I² 99.1%). The current meta-analysis revealed changing the DED had no significant effect on hunger but increased fullness. More high-quality RCTs are needed to investigate the effects of DED on appetite components.

Impact of Nutrient Type and Sequence on Glucose Tolerance: Physiological Insights and Therapeutic Implications

Pharmacological and dietary interventions targeting postprandial glycemia have proved effective in reducing the risk for type 2 diabetes and its cardiovascular complications. Besides meal composition and size, the timing of macronutrient consumption during a meal has been recently recognized as a key regulator of postprandial glycemia. Emerging evidence suggests that premeal consumption of non-carbohydrate macronutrients (i.e., protein and fat "preloads") can markedly reduce postprandial glycemia by delaying gastric emptying, enhancing glucose-stimulated insulin release, and decreasing insulin clearance. The same improvement in glucose tolerance is achievable by optimal timing of carbohydrate ingestion during a meal (i.e., carbohydrate-last meal patterns), which minimizes the risk of body weight gain when compared with nutrient preloads. The magnitude of the glucose-lowering effect of preload-based nutritional strategies is greater in type 2 diabetes than healthy subjects, being comparable and additive to current glucose-lowering drugs, and appears sustained over time. This dietary approach has also shown promising results in pathological conditions characterized by postprandial hyperglycemia in which available pharmacological options are limited or not cost-effective, such as type 1 diabetes, gestational diabetes, and impaired glucose tolerance. Therefore, preload-based nutritional strategies, either alone or in combination with pharmacological treatments, may offer a simple, effective, safe, and inexpensive tool for the prevention and management of postprandial hyperglycemia. Here, we survey these novel physiological insights and their therapeutic implications for patients with diabetes mellitus and altered glucose tolerance.