Systematic review of the evidence for sustained efficacy of dietary interventions for reducing appetite or energy intake.

We assessed evidence for changes in efficacy of food-based interventions aimed at reducing appetite or energy intake (EI), and whether this could be used to provide guidance on trial design. A systematic search identified randomized controlled trials testing sustained efficacy of diets, foods, supplements or food ingredients on appetite and/or EI. Trials had to include sufficient exposure duration (≥3 days) with appetite and/or EI measured after both acute and repeated exposures. Twenty-six trials met the inclusion criteria and reported data allowing for assessment of the acute and chronic effects of interventions. Most (21/26) measured appetite outcomes and over half (14/26) had objective measures of EI. A significant acute effect of the intervention was retained in 10 of 12 trials for appetite outcomes, and six of nine studies for EI. Initial effects were most likely retained where these were more robust and studies adequately powered. Where the initial, acute effect was not statistically significant, a significant effect was later observed in only two of nine studies for appetite and none of five studies for EI. Maintenance of intervention effects on appetite or EI needs to be confirmed but seems likely where acute effects are robust and replicable in adequately powered studies.

Dietary carbohydrates: a review of international recommendations and the methods used to derive them.

BACKGROUND/OBJECTIVES: Renewed dietary recommendations for carbohydrates have recently been published by various international health authorities. The present work (1) reviews the methods and processes (systematic approach/review, inclusion of public consultation) used to identify, select and grade the evidence underpinning the recommendations, particularly for total carbohydrate (CHO), fibre and sugar consumption, and (2) examines the extent to which variation in the methods and processes applied relates to any differences in the final recommendations. SUBJECTS/METHODS: A search of WHO, US, Canada, Australia and European sources identified 19 documents from 13 authorities with the desired detailed information. Processes and methods applied to derive recommendations were compiled and compared. RESULTS: (1) A relatively high total CHO and fibre intake and limited intake of (added or free) sugars are generally recommended. (2) Even where recommendations are similar, the specific justifications for quantitative/qualitative recommendations differ across authorities. (3) Differences in recommendations mainly arise from differences in the underlying definitions of CHO exposure and classifications, the degree to which specific CHO-providing foods and food components were considered, and the choice and number of health outcomes selected. (4) Differences in the selection of source material, time frames or data aggregation and grading methods appeared to have minor influence. CONCLUSIONS: Despite general consistency, apparent differences among the recommendations of different authorities would likely be minimized by: (1) More explicit quantitative justifications for numerical recommendations and communication of uncertainty, and (2) greater international harmonization, particularly in the underlying definitions of exposures and range of relevant nutrition-related outcomes.

Sweet taste exposure and the subsequent acceptance and preference for sweet taste in the diet: systematic review of the published literature.

Background: There are consistent, evidence-based global public health recommendations to reduce intakes of free sugars. However, the corresponding evidence for recommending reduced exposure to sweetness is less clear. Objective: Our aim was to identify and review the published evidence investigating the impact of dietary exposure to sweet-tasting foods or beverages on the subsequent generalized acceptance, preference, or choice of sweet foods and beverages in the diet. Design: Systematic searches were conducted to identify all studies testing relations of variation in exposure to sweetness through foods and beverages with subsequent variation in the generalized acceptance, preference, or choice of sweetened foods or beverages, in humans aged >6 mo. Results: Twenty-one studies met our inclusion criteria, comprising 7 population cohort studies involving 2320 children and 14 controlled trials involving 1113 individuals. These studies were heterogeneous in study design, population, exposure, and outcomes measured, and few were explicitly designed to address our research question. The findings from these were inconsistent. We found equivocal evidence from population cohort studies. The evidence from controlled studies suggests that a higher sweet taste exposure tends to lead to reduced preferences for sweetness in the shorter term, but very limited effects were found in the longer term. Conclusions: A small and heterogeneous body of research currently has considered the impact of varying exposure to sweet taste on subsequent generalized sweet taste preferences, and this evidence is equivocal regarding the presence and possible direction of a relation. Future work should focus on adequately powered studies with well-characterized exposures of sufficient duration. This review was registered with PROSPERO as CRD42016051840, 24 November 2016.

Does low-energy sweetener consumption affect energy intake and body weight? A systematic review, including meta-analyses, of the evidence from human and animal studies.

By reducing energy density, low-energy sweeteners (LES) might be expected to reduce energy intake (EI) and body weight (BW). To assess the totality of the evidence testing the null hypothesis that LES exposure (versus sugars or unsweetened alternatives) has no effect on EI or BW, we conducted a systematic review of relevant studies in animals and humans consuming LES with ad libitum access to food energy. In 62 of 90 animal studies exposure to LES did not affect or decreased BW. Of 28 reporting increased BW, 19 compared LES with glucose exposure using a specific 'learning' paradigm. Twelve prospective cohort studies in humans reported inconsistent associations between LES use and body mass index (-0.002 kg m(-)(2) per year, 95% confidence interval (CI) -0.009 to 0.005). Meta-analysis of short-term randomized controlled trials (129 comparisons) showed reduced total EI for LES versus sugar-sweetened food or beverage consumption before an ad libitum meal (-94 kcal, 95% CI -122 to -66), with no difference versus water (-2 kcal, 95% CI -30 to 26). This was consistent with EI results from sustained intervention randomized controlled trials (10 comparisons). Meta-analysis of sustained intervention randomized controlled trials (4 weeks to 40 months) showed that consumption of LES versus sugar led to relatively reduced BW (nine comparisons; -1.35 kg, 95% CI -2.28 to -0.42), and a similar relative reduction in BW versus water (three comparisons; -1.24 kg, 95% CI -2.22 to -0.26). Most animal studies did not mimic LES consumption by humans, and reverse causation may influence the results of prospective cohort studies. The preponderance of evidence from all human randomized controlled trials indicates that LES do not increase EI or BW, whether compared with caloric or non-caloric (for example, water) control conditions. Overall, the balance of evidence indicates that use of LES in place of sugar, in children and adults, leads to reduced EI and BW, and possibly also when compared with water.

The effect of a low-energy food foam on appetite measures during a 1-day reduced-energy meal plan.

BACKGROUND/OBJECTIVES: We have previously shown that 500 ml of a foamed drink ('foam') significantly improved appetite versus a non-foamed control. The objectives of this research were to assess the effect of smaller volumes of foams on appetite, and the potential benefits of foam ingestion and its timing on appetite measures in a reduced-energy context. SUBJECTS/METHODS: Two randomized, parallel design studies (pre- and main study) were conducted using healthy adult subjects. Pre-study: 133 subjects (age 18-50 years, body mass index (BMI) 20-32 kg m(-2)) each consumed either 10, 25, 50, 100, 150 or 250 ml foamed meal replacer (~0.2 kcal ml(-1)), 150 min after a fixed breakfast. Main study: four groups of subjects (n=134; age 18-60 years, BMI 22.5-35.0 kg m(-2)) consumed 200 ml/22 kcal foam (based on pre-study results) immediately after main meals (M), after snacks (S), in-between snacks and main meals (I) or not at all (control, C) within 1 day of a reduced-energy meal plan consisting of three main meals and three snacks. Measurements included self-reported appetite (six scales, reported as area under the curve (AUC)) and (main study only) end-of-day appetite questionnaire. RESULTS: Pre-study: the strongest effect on appetite was produced by 250 ml (consistent across scales), whereas 150 ml showed more pronounced effects than 100 and 50 ml in most scales. Volumes 10 and 25 ml had no effects on any scale. Main study: 200 ml foam reduced appetite AUC substantially in all treatments, particularly M (for example, hunger AUC reduced by 35% (P <0.001), 28% (P <0.05) and 20% (P=0.11) for M, S and I, respectively versus C). A strong reduction in 'appetite for a snack' was seen for all timings (all P <0.05). The end-of-day appetite ratings confirmed these findings. CONCLUSIONS: Modest amounts of a low-energy foam can reduce appetite measures during a 1-day reduced-energy meal plan.

Potential benefits of satiety to the consumer: scientific considerations.

Foods and dietary patterns that enhance satiety may provide benefit to consumers. The aim of the present review was to describe, consider and evaluate research on potential benefits of enhanced satiety. The proposal that enhanced satiety could only benefit consumers by a direct effect on food intake should be rejected. Instead, it is proposed that there is a variety of routes through which enhanced satiety could (indirectly) benefit dietary control or weight-management goals. The review highlights specific potential benefits of satiety, including: providing appetite control strategies for consumers generally and for those who are highly responsive to food cues; offering pleasure and satisfaction associated with low-energy/healthier versions of foods without feeling 'deprived'; reducing dysphoric mood associated with hunger especially during energy restriction; and improved compliance with healthy eating or weight-management efforts. There is convincing evidence of short-term satiety benefits, but only probable evidence for longer-term benefits to hunger management, possible evidence of benefits to mood and cognition, inadequate evidence that satiety enhancement can promote weight loss, and no evidence on which consumers would benefit most from satiety enhancement. The appetite-reducing effects of specific foods or diets will be much more subtle than those of pharmaceutical compounds in managing hunger; nevertheless, the experience of pharmacology in producing weight loss via effects on appetite suggests that there is potential benefit of satiety enhancement from foods incorporated into the diet to the consumer.

Acute effects of mustard, horseradish, black pepper and ginger on energy expenditure, appetite, ad libitum energy intake and energy balance in human subjects.

Chilli peppers have been shown to enhance diet-induced thermogenesis (DIT) and reduce energy intake (EI) in some studies, but there are few data on other pungent spices. The primary aim of the present study was to test the acute effects of black pepper (pepper), ginger, horseradish and mustard in a meal on 4 h postprandial DIT. The secondary aim was to examine the effects on subjective appetite measures, ad libitum EI and energy balance. In a five-way placebo-controlled, single-blind, cross-over trial, twenty-two young (age 24·9 (SD 4·6) years), normal-weight (BMI 21·8 (SD 2·1) kg/m²) males were randomly assigned to receive a brunch meal with either pepper (1·3 g), ginger (20 g), horseradish (8·3 g), mustard (21 g) or no spices (placebo). The amounts of spices were chosen from pre-testing to make the meal spicy but palatable. No significant treatment effects were observed on DIT, but mustard produced DIT, which tended to be larger than that of placebo (14 %, 59 (SE 3) v. 52 (SE 2) kJ/h, respectively, P=0·08). No other spice induced thermogenic effects approaching statistical significance. Subjective measures of appetite (P>0·85), ad libitum EI (P=0·63) and energy balance (P=0·67) also did not differ between the treatments. Finally, horseradish decreased heart rate (P=0·048) and increased diastolic blood pressure (P= 0·049) compared with placebo. In conclusion, no reliable treatment effects on appetite, EI or energy balance were observed, although mustard tended to be thermogenic at this dose. Further studies should explore the possible strength and mechanisms of the potential thermogenic effect of mustard actives, and potential enhancement by, for example, combinations with other food components.

No appetite efficacy of a commercial structured lipid emulsion in minimally processed drinks.

BACKGROUND/OBJECTIVES: Fabuless (Olibra) is a commercially structured lipid emulsion, claimed to be a food ingredient that is effective for food intake and appetite reduction. The present study assessed its efficacy in a yoghurt-based mini-drink undergoing low or minimal food manufacturing (thermal and shear) processes. SUBJECTS/METHODS: Study 1: Twenty-four healthy volunteers (16 female, 8 male; age: 18-47 years; body mass index (BMI): 17-28 kg m(-2)) took part in a randomised, placebo-controlled, double-blind parallel crossover trial. Consumption of a minimally processed 'preload' mini-drink (containing two different doses of Fabuless or a control fat) at 2 h after breakfast was followed by appetite and mood ratings, and food intake measured in ad libitum meals at 3 and 7 h post consumption of the preload. Study 2: As Study 1 (16 female, 8 male; age: 20-54 years; BMI: 21-30 kg m(-2)). A chilled, virtually unprocessed, preload breakfast mini-drink (containing minimally processed Fabuless or a control fat) was provided 5 min after a standardised breakfast, followed by appetite and mood ratings, and food intake measured in ad libitum meals at 4 and 8 h post consumption of the preload. RESULTS: The structured lipid emulsion tested had no significant effect on the primary measures of food intake or appetite. CONCLUSIONS: Even when exposed to minimal food-manufacturing conditions, Fabuless showed no efficacy on measures of appetite and food intake.

The effect of protease inhibitors derived from potato formulated in a minidrink on appetite, food intake and plasma cholecystokinin levels in humans.

BACKGROUND: Protease inhibitor 2 derived from potato (PI2) is claimed to reduce appetite and food intake, stimulate the satiety hormone cholecystokinin (CCK) and lower postprandial glucose peaks when taken before a meal. However, current literature is inconclusive with regard to its efficacy and mechanism. Furthermore, the potential effect of PI2 on appetite motivational ratings without an immediately following meal has not previously been reported. OBJECTIVE: To comprehensively test the effects of 30 mg PI2 in a minidrink on appetite ratings, subsequent food intake, and plasma CCK and glucose responses. DESIGN: Minidrinks with or without 30 mg PI2 were compared in three separate substudies (A, B and C), each using a two-way, placebo-controlled, balanced-order, cross-over design and 23 or 24 subjects (mean over groups: body mass index 25.0 kg m(-2), range 22.5-30.7 kg m(-2); age 41.3, range 18-62 years). The minidrink was given (A) 120 or (B) 30 min before an ad libitum lunch or (C) 30 min before a fixed lunch. Study parameters were self-reported satiety (substudies A and C), ad libitum meal intake (substudies A and B), and (in an n=12 subset) plasma CCK and blood glucose in all substudies. All results were analyzed using analysis of covariance. Protease-inhibitory activity of the PI2-containing minidrinks was assessed under simulated gut conditions. RESULTS: PI2 did not differ from control for any study parameters, in any substudy, despite confirmation of the inhibitory activity of PI2. CONCLUSIONS: In this study protease inhibition using PI2 in a minidrink at a dose of 30 mg, as commercially used, had no (functional) efficacy on a range of behavioral and physiological appetite and intake control measures.

Effect of carbohydrate digestibility on appetite and its relationship to postprandial blood glucose and insulin levels.

BACKGROUND/OBJECTIVES: 'Slowly digestible' carbohydrates have been claimed to reduce appetite through their effects on postprandial glucose and insulin levels, but literature is inconsistent. The inconsistencies between studies might be explained by factors other than glycemic effects per se, for example, nutritional or physical properties. We tested this possibility by examining postprandial glucose, insulin and appetite responses to drinks differing only in rate and extent of digestibility of carbohydrates. This was accomplished by comparing different glucose polymers: maltodextrin (rapidly digestible) versus medium-chain pullulan (slowly but completely digestible) versus long-chain pullulan (indigestible). SUBJECTS/METHODS: In a randomized double-blind balanced crossover design, 35 subjects received drinks with 15 g test carbohydrate polymers. Key outcome measures were appetite scores, digestibility (in vitro test and breath hydrogen), and (in a subset) glucose and insulin levels. RESULTS: Digestibility, glucose and insulin data confirmed the rapid, slow and nondigestible nature of the test carbohydrates. Despite its low digestibility, only long-chain pullulan reduced appetite compared with the maltodextrin control, whereas the medium-chain pullulan did not. CONCLUSIONS: We conclude that glycemic responses per se have minimal effects on appetite, when tested in products differing in only carbohydrate digestibility rate and extent.

No efficacy of processed Fabuless (Olibra) in suppressing appetite or food intake.

BACKGROUND/OBJECTIVES: To investigate the feasibility of Fabuless (previously called Olibra and Reducal) as a food ingredient for food intake and appetite reduction, by assessing the effects of food processing on efficacy. SUBJECTS/METHODS: In total, 24 healthy volunteers (16 female, 8 male; age: 18-43 years; body mass index: 18-37 kg/m(2)) took part in a randomized, placebo-controlled, double-blinded, cross-over trial. Yoghurt-based meal replacement drinks (containing processed or unprocessed Fabuless, or a control fat) were followed by an ad libitum lunch and evening meal (dinner). Key outcome measures were energy intake and self-reported appetite ratings. RESULTS: Compared with control, only unprocessed Fabuless reduced subsequent energy intake, although only during dinner (P < 0.01; control, processed and unprocessed: 4.3, 3.9 and 4.2 MJ, respectively) and not during lunch (3.6, 3.7 and 3.6 MJ). Self-reported appetite scores did not differ between treatments. CONCLUSIONS: Although modest effects of unprocessed Fabuless were seen on food intake, but not on appetite, the ingredient was not robust to common food-manufacturing processes (thermal and shear processing). Claims on reduced food intake and appetite relating to this ingredient in food products are, therefore, only valid if functionality has been demonstrated after all relevant processing and storage steps.

Ileal brake: a sensible food target for appetite control. A review.

With the rising prevalence of obesity and related health problems increases, there is increased interest in the gastrointestinal system as a possible target for pharmacological or food-based approaches to weight management. Recent studies have shown that under normal physiological situations undigested nutrients can reach the ileum, and induce activation of the so-called "ileal brake", a combination of effects influencing digestive process and ingestive behaviour. The relevance of the ileal brake as a potential target for weight management is based on several findings: First, activation of the ileal brake has been shown to reduce food intake and increase satiety levels. Second, surgical procedures that increase exposure of the ileum to nutrients produce weight loss and improved glycaemic control. Third, the appetite-reducing effect of chronic ileal brake activation appears to be maintained over time. Together, this evidence suggests that activation of the ileal brake is an excellent long-term target to achieve sustainable reductions in food intake. This review addresses the role of the ileal brake in gut function, and considers the possible involvement of several peptide hormone mediators. Attention is given to the ability of macronutrients to activate the ileal brake, and particularly variation attributable to the physicochemical properties of fats. The emphasis is on implications of ileal brake stimulation on food intake and satiety, accompanied by evidence of effects on glycaemic control and weight loss.

Metabolically active functional food ingredients for weight control.

The scale of the obesity epidemic creates a pressing consumer need as well as an enormous business opportunity for successful development and marketing of food products with added benefits for weight control. A number of proposed functional food ingredients have been shown to act post-absorptively to influence substrate utilization or thermogenesis. Characteristics and supporting data on conjugated linoleic acid, diglycerides, medium-chain triglycerides, green tea, ephedrine, caffeine, capsaicin and calcium, are reviewed here, giving examples of how these could act to alter energy expenditure or appetite control. Consideration is also given to other factors, in addition to efficacy, which must be satisfied to get such ingredients into foods. We conclude that, for each of the safe, putatively metabolically active agents, there remain gaps in clinical evidence or knowledge of mechanisms, which need to be addressed in order to specify the dietary conditions and food product compositions where these ingredients could be of most benefit for weight control.

Effects of learned flavour cues on short-term regulation of food intake in a realistic setting.

The present study examined the effects of repeated midmorning consumption of novel-flavoured low- and high-energy yoghurt drinks on subsequent energy intake at lunch in 69 adults under actual use conditions. Subjects consumed 200 ml of low- and high-energy yoghurt drinks (67 and 273 kcal/200 ml, respectively), with 20 exposures to each drink on alternate days. Analyses focused on the development of compensation for the differences in energy content of the beverages, due to learned satiety. Results revealed incomplete energy compensation for the beverages, both at first exposure and also after 20 exposures. Relative to the no-yoghurt condition, energy intake compensation (+/-S.E.M.) averaged 39+/-36% for the low-energy yoghurt and 17+/-9% for the high-energy version, with no evidence of any change in compensation with repeated exposures. When the flavours of the yoghurt drinks were covertly switched after 20 exposures, subjects increased their energy intake after the high-energy yoghurt drink containing the flavour that was previously coupled with the low-energy yoghurt drink. Vice versa, however, when subjects switched to the low-energy yoghurt drink containing the high-energy flavour, subjects ignored the flavour cue and ate the same lunch size regardless of the energy in the yoghurt drink. We conclude that adults do not readily acquire accurate conditioned adjustments for the energy content in food after repeated experience with the food in free-living natural-eating conditions.

Determinants of food choice: relationships with obesity and weight control.

The decision to eat, and to eat particular foods, varies for different individuals and situations. Individual differences in food likes and desires develop throughout life because of differing food experiences and attitudes. There are many internal and external cues, not just stimulation from foods or hunger, which can trigger the immediate desire to eat or orient eating toward certain foods. Food desires and intake are an outcome of interactions between these cues and more stable individual physiological and psychological characteristics. Overweight and obese individuals show a tendency toward greater liking and selection of energy-dense foods, which may contribute to development and maintenance of these conditions. However, although liking (pleasure from eating) is an important part of food choice, it may make only a modest contribution to overall variation in food choice and eating behaviors. Indeed, difficulties of weight control may reflect problems with cues and motivations to eat, rather than with heightened pleasure derived from eating. Paradoxically, individuals highly concerned with food intake and weight control may be particularly susceptible to thoughts, emotions, and situational cues that can prompt overeating and undermine their attempts to restrain eating. Repeat dieting, high day-to-day fluctuations in intakes, and attempts to enforce highly rigid control over eating all seem to be counterproductive to weight control efforts and may disrupt more appropriate food choice behaviors. Longer-term weight maintenance solutions and programs that offer a degree of structuring of the personal food environment, while retaining flexibility in choices, therefore, may be particularly beneficial in weight management.

Differences in health and taste attitudes and reported behaviour among Finnish, Dutch and British consumers: a cross-national validation of the Health and Taste Attitude Scales (HTAS).

The Health and Taste Attitude Scales (HTAS) developed by Roininen, Lähteenmäki and Tuorila in 1999 measure the importance of health and taste aspects of foods in the food choice process. These multi-item scales consist of sets of statements, ranging from "strongly disagree" to "strongly agree", which further divide into three Health (General health interest, Light product interest and Natural product interest) and three Taste (Craving for sweet foods, Using food as a reward and Pleasure) sub-scales. Finnish (N=467), Dutch (N=477), and British (N=361) respondents completed a questionnaire which contained four components: the HTAS, a separate "paper and pencil task" of choosing a food for a snack; pleasantness, healthiness and frequency of consumption of eight foods; and the Restraint Eating Scale of the Dutch Eating Behaviour Questionnaire (DEBQ). The latter three components were included in order to validate various aspects of the HTAS. The factor structure of HTAS was found to be equal in all three countries. However, there were some minor differences in factor loadings among countries, e.g. the Natural product interest and Pleasure sub-scale items had lower factor loadings in the UK than in Finland and The Netherlands. Finnish respondents had the most positive attitude towards light products. Dutch and British respondents scored higher on all Taste sub-scales than their Finnish counterparts. Respondents' health-related attitudes were good predictors of their "healthy food choices" in the snack task and self-reported consumption. Two of the Taste sub-scales (Craving for sweet foods and Using food as a reward) predicted well respondents' self-reported consumption of, for example, full-fat chocolate bars. All the Health and two of the Taste sub-scales proved to be useful tools for characterizing consumer attitudes within and between countries.

UK consumer perceptions of starchy foods.

To gain an understanding of UK consumer attitudes and beliefs regarding starchy foods and their dietary role, a questionnaire based on the theory of planned behaviour was developed and sent out to a UK consumer sample (n 800). The content focused on attitudes and beliefs towards starchy foods, perceived barriers towards increasing their intake (e.g. cost, habit, social influences), perceptions of personal and recommended starchy food intake, intention to increase starchy food intakes in the future and socio-demographic information. Responses (n 414) indicated that consumers have highly divergent attitudes and beliefs regarding starchy foods. These foods are seen as nutritious and good for one's health, but also as high in energy and not helping to control weight, and the overall intention to increase starchy food intake was extremely low. Possible barriers towards increasing starchy food intake were the perceptions that personal starchy food intakes were already high, beliefs that starchy food intakes should be reduced to achieve a healthier diet, and the view that personal starchy food intakes did not need to be changed any further, because (depending on attitude) individual's intakes had already been increased or reduced. The model including attitude and subjective norm had the best fit for predicting reported intention to increase starchy food consumption, with attitude being the strongest contributor. Addition of the factor 'family's liking of starchy foods' significantly improved the model. For reported starch intake, the model including attitude had the best fit, and addition of other factors did not improve the model. These findings indicate that health promotion strategies aimed at increasing complex carbohydrate intakes should take these perceptions into consideration; however, further work is required to examine how these potential barriers can best be addressed in practice.

Short- and long-term effects of changes in pleasantness on food intake.

This study concerns the effects of pleasantness on ad libitum food intake, liking and appetite over 5 successive days. Pleasantness was manipulated by varying the salt level in bread. Thirty-five students consumed ad libitum sandwiches for lunch, made with bread individually perceived as low, medium or high in pleasantness, in a balanced cross-over design. Pleasantness and desire-to-eat the sandwich were rated at first bite, after the consumption of each sandwich and at the end of the lunch. Fullness was rated just before and at several intervals after lunch. On the first day, the students ate less of the least pleasant bread than of the medium and most pleasant bread. On the fifth day, however, consumption of all breads was similar. For the least pleasant bread, energy intake at lunch, desire-to-eat and fullness, all increased over days, whereas these variables remained constant for the medium and most pleasant bread. Mean pleasantness ratings for all breads remained unaltered across the days. We conclude that, with repeated exposure, the desire-to-eat, fullness and intake of a less preferred food can increase over time. Thus, the relationship between pleasantness and food intake changes over this period.

Determination of energy density of freely selected diets: methodological issues and implications.

BACKGROUND: There is increasing evidence that dietary energy density (ED, kJ/g) may be an important dietary characteristic, particularly in respect to control of energy intake; however, there are no agreed methods for deriving the ED of freely selected diets, and ED values may be markedly affected by the inclusion or exclusion of specific dietary items, particularly beverages. OBJECTIVE: To highlight the consequences of using six different methods of ED calculation, and their implications for characterizing differences between weight status groups and identifying associations of ED with macronutrient intakes. DESIGN: ED was calculated using six defined methods: (1) all food and beverages; (2) all food and energy beverages; (3) food, milk and alcohol; (4) food only; (5) all dry matter; (6) protein, carbohydrate and fat only, of varying exclusions of different beverages and water. For illustrative purposes, data from 41 lean (LE, body mass index (BMI) 20-25 kg/m2) and 34 obese (OB, BMI>/=30 kg/m2) adults who kept 4-day weighed dietary intake records are described. RESULTS: ED values (and coefficient of variation, CV) differed substantially by methods of calculation. OB reported significantly greater mean ED compared with LE by one method (all food, milk and alcohol, excluding other non-alcoholic beverages); however, the opposite was found using another method (dry weight). For most calculation methods, ED was negatively associated with percentage energy from carbohydrate for LE, in contrast to OB. All methods found positive correlations for ED and fat (g) among LE, but only one method found such a correlation among OB. Similarly, three methods produced positive correlations between ED and percentage energy fat amongst LE; however, this was only observed amongst OB with one method. CONCLUSIONS: Methods of calculating ED of freely selected diets must be carefully defined, and can markedly influence apparent relationships of ED with other dietary measures and subject characteristics. International Journal of Obesity (2000)24, 49-54

Food choice and intake: the human factor.

Human perceptions and selection of food are derived from the prevailing and momentary food, agro-economic and cultural environment, cognitive and biological characteristics of individuals, and the real and perceived intrinsic and extrinsic attributes of foods themselves. The range of items typically chosen and consumed within a given population is largely determined by interaction of the external environmental context with guiding sets of implicit and explicit social and psychobiological 'rules'. Within the rather broad limits of biology, individual food choices and intake behaviours relate to and reflect aspects of food availability, existing habitual behaviours, learning mechanisms, and individual beliefs and expectations. Many of the relevant features of these variables are uniquely human, together determining what is 'food', when, how, by and with whom it is chosen and eaten, and in what quantities. They also provide the opportunities for individuals to establish and maintain a relatively stable set of culturally and biologically determined affective responses ('likes') and intake behaviours. Understanding of the potential contribution of these influences under different conditions can serve to explain many of the observed characteristics of human eating, and highlight potential avenues for intervention.