Does nutrition information about the energy density of meals affect food intake in normal-weight women?

Impact of energy density on energy intake in children and adults: a systematic review and meta-analysis of randomized controlled trials

PURPOSE

The energy density (ED) of a diet can be leveraged to prevent weight gain or treat overweight and obesity. By lowering the ED of the diet, energy intake can be reduced while maintaining portion size. However, a reliable meta-analysis of data from randomized controlled trials (RCTs) is missing. Therefore, this meta-analysis synthesized the evidence of ED manipulation on energy intake in RCTs.

METHODS

The systematic literature search of multiple databases according to PRISMA criteria considered RCTs investigating the objectively measured energy intake from meals with different ED (lower ED (median 1.1 kcal/g) versus higher ED (median 1.5 kcal/g)) under controlled conditions. Subgroup analyses for age (children versus adults), meal type (preload versus entrée design), and intervention length (1 meal versus > 1 meal) were performed to achieve the most homogeneous result.

RESULTS

The meta-analysis of 38 included studies demonstrated that lowering ED considerably reduced energy intake - 223 kcal (95% CI: - 259.7, - 186.0) in comparison to the higher ED interventions. As heterogeneity was high among studies, subgroup analyses were conducted. Heterogeneity decreased in subgroup analyses for age and meal type combined, strengthening the results. An extended analysis showed a positive linear relationship between ED and energy intake. Dietary ED did not affect the amount of food intake.

CONCLUSION

Manipulating ED substantially affects energy intake whereas food intake remains constant. Thus, this approach can be regarded as a powerful tool for weight management through nutrition therapy. Registration on 08/08/2021: CRD42021266653.

Time to revisit the passive overconsumption hypothesis? Humans show sensitivity to calories in energy-rich meals

BACKGROUND

A possible driver of obesity is insensitivity (passive overconsumption) to food energy density (ED, kcal/g); however, it is unclear whether this insensitivity applies to all meals.

OBJECTIVES

We assessed the influence of ED on energy intake (kcal) across a broad and continuous range of EDs comprised of noncovertly manipulated, real-world meals. We also allowed for the possibility that the association between energy intake and ED is nonlinear.

METHODS

We completed a secondary analysis of 1519 meals which occurred in a controlled environment as part of a study conducted by Hall and colleagues to assess the effects of food ultra-processing on energy intake. To establish the generalizability of the findings, the analyses were repeated in 32,162 meals collected from free-living humans using data from the UK National Diet and Nutrition Survey (NDNS). Segmented regressions were performed to establish ED "breakpoints" at which the association between consumed meal ED and mean centered meal caloric intake (kcal) changed.

RESULTS

Significant breakpoints were found in both the Hall et al. data set (1.41 kcal/g) and the NDNS data set (1.75 and 2.94 kcal/g). Centered meal caloric intake did not increase linearly with consumed meal ED, and this pattern was captured by a 2-component ("volume" and "calorie content" [biologically derived from the sensing of fat, carbohydrate, and protein]) model of physical meal size (g), in which volume is the dominant signal with lower energy-dense foods and calorie content is the dominant signal with higher energy-dense foods.

CONCLUSIONS

These analyses reveal that, on some level, humans are sensitive to the energy content of meals and adjust meal size to minimize the acute aversive effects of overconsumption. Future research should consider the relative importance of volume and calorie-content signals, and how individual differences impact everyday dietary behavior and energy balance.

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 ).

Comparison of college students' behavior toward nutrition information communication between Korea and the US

BACKGROUND/OBJECTIVES

The expansion of menu labeling to restaurants has created a need to study customers' behavior toward nutrition information. Therefore, the purpose of this research was to compare college students' behavior toward nutrition information communication between Korea and the US. This study consisted of three objectives: 1) to compare the frequency of usage as well as degree of trust regarding smartphone-based communication channels in the acquisition of nutrition information among college students between Korea and the US, 2) to compare knowledge-sharing behavior related to nutrition information among college students between Korea and the US, and 3) to identify the role of country in the process of knowledge-sharing behavior.

SUBJECTS/METHODS

A survey was distributed via the web to college students in Korea and the US. Data were collected in the 2nd week of March 2017. Completed responses were collected from 423 Koreans and 280 Americans. Differences between Koreans and Americans were evaluated for statistical significance using a t-test. In order to verify the effects of knowledge self-efficacy and transactive memory capability on knowledge-sharing behavior related to nutrition information, a regression analysis was performed.

RESULTS

Significant differences were found in the frequency of usage as well as degree of trust in communication channels related to nutrition information between Korean and American college students. While knowledge self-efficacy and tractive memory capability had positive effects on knowledge-sharing behavior related to nutrition information, country had a significant effect on the process.

CONCLUSIONS

This study is the first to compare customer behavior toward nutrition information acquisition and sharing between Korea and the US. Comparative research on nutrition information revealed differences among the different countries. Therefore, this study contributes to the body of knowledge on the nutrition information research, in particular, by providing a comparison study between countries.

Customers' perception of the attributes of different formats of menu labeling: a comparison between Korea and the U.S

BACKGROUND/OBJECTIVES

This study compared the perception of customers from Korea and the U.S. on the attributes of different formats of menu labeling The specific objectives were 1) to compare the customers' perceived usefulness, ease-of-understanding, clarity, and attractiveness of different formats of menu labeling between Korea and the U.S.; and 2) to compare the customers' use intention to different formats of menu labeling between Korea and the U.S.

SUBJECTS/METHODS

A survey was conducted in Korea and the U.S. The participants were allocated randomly to view 1 of the 7 restaurant menus that varied according to the following types of menu labeling formats: (type 1) kcal format, (type 2) traffic-light format, (type 3) percent daily intake (%DI) format, (type 4) kcal + traffic-light format, (type 5) kcal + %DI format, (type 6) traffic-light + %DI format, and (type 7) kcal + traffic-light + %DI format. A total of 279 Koreans and 347 Americans were entered in the analysis. An independent t-test and 1-way analysis of variance were performed.

RESULTS

Koreans rated type 4 format (kcal + traffic light) the highest for usefulness and attractiveness. In contrast, Americans rated type 7 (kcal + traffic light + %DI) the highest for usefulness, ease-of-understanding, attractiveness, and clarity. Significant differences were found in the customers' perceived attributes to menu labeling between Korea and the U.S. Americans perceived higher for all the 4 attributes of menu labeling than Koreans.

CONCLUSIONS

The study is unique in identifying the differences in the attributes of different formats of menu labeling between Korea and the U.S. Americans rated the most complicated type of menu labeling as the highest perception for the attributes, and showed a higher use intention of menu labeling than Koreans. This study contributes to academia and industry for practicing menu labeling in different countries using different formats.

Influence of the nutrition and health information presented on food labels on portion size consumed: a systematic review

Context

In recent decades, portion sizes have increased significantly. Although previous research indicates that food labels impact on product choice and healthiness perception, their impact on portion sizes consumed is less clear.

Objective

This systematic review examined whether food label information influenced portion size consumption.

Data sources

A search of 7 major electronic databases for studies published from 1980 to April 2016 was conducted.

Data extraction

Two reviewers independently screened 11 128 abstracts. Data were extracted from 32 articles (comprising 36 studies).

Results

Based on the test food used, the overall effects were found to be: no effect, a positive effect, or a negative effect. Labels displaying energy content (n = 15 studies, 17 effects) and fat content information (n = 13 studies, 14 effects) were evaluated most commonly, with exercise equivalent labels evaluated least (n = 2 studies, 2 effects).

Conclusions

Nutrition and health information presented on food labels has varying impacts on portion sizes consumed, from increased to decreased intake. Recommendations for future research include evaluating more recent food label types and achieving more consistent reporting standards.

A Meta-Analysis of Food Labeling Effects on Consumer Diet Behaviors and Industry Practices

CONTEXT

The influence of food and beverage labeling (food labeling) on consumer behaviors, industry responses, and health outcomes is not well established.

EVIDENCE ACQUISITION

PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-Analyses) guidelines were followed. Ten databases were searched in 2014 for studies published after 1990 evaluating food labeling and consumer purchases/orders, intakes, metabolic risk factors, and industry responses. Data extractions were performed independently and in duplicate. Studies were pooled using inverse-variance random effects meta-analysis. Heterogeneity was explored with I2, stratified analyses, and meta-regression; and publication bias was assessed with funnel plots, Begg's tests, and Egger's tests. Analyses were completed in 2017.

EVIDENCE SYNTHESIS

From 6,232 articles, a total of 60 studies were identified, including 2 million observations across 111 intervention arms in 11 countries. Food labeling decreased consumer intakes of energy by 6.6% (95% CI= -8.8%, -4.4%, n=31), total fat by 10.6% (95% CI= -17.7%, -3.5%, n=13), and other unhealthy dietary options by 13.0% (95% CI= -25.7%, -0.2%, n=16), while increasing vegetable consumption by 13.5% (95% CI=2.4%, 24.6%, n=5). Evaluating industry responses, labeling decreased product contents of sodium by 8.9% (95% CI= -17.3%, -0.6%, n=4) and artificial trans fat by 64.3% (95% CI= -91.1%, -37.5%, n=3). No significant heterogeneity was identified by label placement or type, duration, labeled product, region, population, voluntary or legislative approaches, combined intervention components, study design, or quality. Evidence for publication bias was not identified.

CONCLUSIONS

From reviewing 60 intervention studies, food labeling reduces consumer dietary intake of selected nutrients and influences industry practices to reduce product contents of sodium and artificial trans fat.

Feeling the weight of calories: using haptic feedback as virtual exemplars to promote risk perception among young females on unhealthy snack choices

Virtual simulations allow users to feel and manipulate objects as they would in the physical world. Guided by exemplification theory and risk communication research, a virtual exemplar was developed to allow users to feel the weight of the caloric density of unhealthy snacks (e.g., potato chips) to heighten risk perceptions on snack choices. A 3 (base-rate statistics, print exemplar, virtual exemplar) × 3 (Time 1, Time 2, Time 3) mixed design experiment (N = 152) compared the effect of three mediated modes of delivering health information at baseline, immediately after, and 1 week after treatments. Virtual exemplars led to greater spatial presence, issue involvement, and recommended health behavior than did base-rate statistics or print exemplars, but had no effect on perceived vividness. Heightened perceived susceptibility following virtual exemplars persisted for 1 week. Findings emphasized the importance of spatial presence elicited by an exemplar in heightening the perceived susceptibility of health risks both immediately after and 1 week after exposure. The role of spatial presence and vividness in the context of virtual exemplars that afford the illusion of firsthand experiences is discussed and compared against traditional exemplification research that has focused on the impact of secondhand experiences.

Nutritional labelling for healthier food or non-alcoholic drink purchasing and consumption

BACKGROUND

Nutritional labelling is advocated as a means to promote healthier food purchasing and consumption, including lower energy intake. Internationally, many different nutritional labelling schemes have been introduced. There is no consensus on whether such labelling is effective in promoting healthier behaviour.

OBJECTIVES

To assess the impact of nutritional labelling for food and non-alcoholic drinks on purchasing and consumption of healthier items. Our secondary objective was to explore possible effect moderators of nutritional labelling on purchasing and consumption.

SEARCH METHODS

We searched 13 electronic databases including CENTRAL, MEDLINE and Embase to 26 April 2017. We also handsearched references and citations and sought unpublished studies through websites and trials registries.

SELECTION CRITERIA

Eligible studies: were randomised or quasi-randomised controlled trials (RCTs/Q-RCTs), controlled before-and-after studies, or interrupted time series (ITS) studies; compared a labelled product (with information on nutrients or energy) with the same product without a nutritional label; assessed objectively measured purchasing or consumption of foods or non-alcoholic drinks in real-world or laboratory settings.

DATA COLLECTION AND ANALYSIS

Two authors independently selected studies for inclusion and extracted study data. We applied the Cochrane 'Risk of bias' tool and GRADE to assess the quality of evidence. We pooled studies that evaluated similar interventions and outcomes using a random-effects meta-analysis, and we synthesised data from other studies in a narrative summary.

MAIN RESULTS

We included 28 studies, comprising 17 RCTs, 5 Q-RCTs and 6 ITS studies. Most (21/28) took place in the USA, and 19 took place in university settings, 14 of which mainly involved university students or staff. Most (20/28) studies assessed the impact of labelling on menus or menu boards, or nutritional labelling placed on, or adjacent to, a range of foods or drinks from which participants could choose. Eight studies provided participants with only one labelled food or drink option (in which labelling was present on a container or packaging, adjacent to the food or on a display board) and measured the amount consumed. The most frequently assessed labelling type was energy (i.e. calorie) information (12/28).Eleven studies assessed the impact of nutritional labelling on purchasing food or drink options in real-world settings, including purchases from vending machines (one cluster-RCT), grocery stores (one ITS), or restaurants, cafeterias or coffee shops (three RCTs, one Q-RCT and five ITS). Findings on vending machines and grocery stores were not interpretable, and were rated as very low quality. A meta-analysis of the three RCTs, all of which assessed energy labelling on menus in restaurants, demonstrated a statistically significant reduction of 47 kcal in energy purchased (MD -46.72 kcal, 95% CI -78.35, -15.10, N = 1877). Assuming an average meal of 600 kcal, energy labelling on menus would reduce energy purchased per meal by 7.8% (95% CI 2.5% to 13.1%). The quality of the evidence for these three studies was rated as low, so our confidence in the effect estimate is limited and may change with further studies. Of the remaining six studies, only two (both ITS studies involving energy labels on menus or menus boards in a coffee shop or cafeteria) were at low risk of bias, and their results support the meta-analysis. The results of the other four studies which were conducted in a restaurant, cafeterias (2 studies) or a coffee shop, were not clearly reported and were at high risk of bias.Seventeen studies assessed the impact of nutritional labels on consumption in artificial settings or scenarios (henceforth referred to as laboratory studies or settings). Of these, eight (all RCTs) assessed the effect of labels on menus or placed on a range of food options. A meta-analysis of these studies did not conclusively demonstrate a reduction in energy consumed during a meal (MD -50 kcal, 95% CI -104.41, 3.88, N = 1705). We rated the quality of the evidence as low, so our confidence in the effect estimate is limited and may change with further studies.Six laboratory studies (four RCTs and two Q-RCTs) assessed the impact of labelling a single food or drink option (such as chocolate, pasta or soft drinks) on energy consumed during a snack or meal. A meta-analysis of these studies did not demonstrate a statistically significant difference in energy (kcal) consumed (SMD 0.05, 95% CI -0.17 to 0.27, N = 732). However, the confidence intervals were wide, suggesting uncertainty in the true effect size. We rated the quality of the evidence as low, so our confidence in the effect estimate is limited and may change with further studies.There was no evidence that nutritional labelling had the unintended harm of increasing energy purchased or consumed. Indirect evidence came from five laboratory studies that involved mislabelling single nutrient content (i.e. placing low energy or low fat labels on high-energy foods) during a snack or meal. A meta-analysis of these studies did not demonstrate a statistically significant increase in energy (kcal) consumed (SMD 0.19, 95% CI -0.14to 0.51, N = 718). The effect was small and the confidence intervals wide, suggesting uncertainty in the true effect size. We rated the quality of the evidence from these studies as very low, providing very little confidence in the effect estimate.

AUTHORS' CONCLUSIONS

Findings from a small body of low-quality evidence suggest that nutritional labelling comprising energy information on menus may reduce energy purchased in restaurants. The evidence assessing the impact on consumption of energy information on menus or on a range of food options in laboratory settings suggests a similar effect to that observed for purchasing, although the evidence is less definite and also of low quality.Accordingly, and in the absence of observed harms, we tentatively suggest that nutritional labelling on menus in restaurants could be used as part of a wider set of measures to tackle obesity. Additional high-quality research in real-world settings is needed to enable more certain conclusions.Further high-quality research is also needed to address the dearth of evidence from grocery stores and vending machines and to assess potential moderators of the intervention effect, including socioeconomic status.

Dietary energy density: Applying behavioural science to weight management

Studies conducted by behavioural scientists show that energy density (kcal/g) provides effective guidance for healthy food choices to control intake and promote satiety. Energy density depends upon a number of dietary components, especially water (0 kcal/g) and fat (9 kcal/g). Increasing the proportion of water or water-rich ingredients, such as vegetables or fruit, lowers a food's energy density. A number of studies show that when the energy density of the diet is reduced, both adults and children spontaneously decrease their ad libitum energy intake. Other studies show that consuming a large volume of a low-energy-dense food such as soup, salad, or fruit as a first course preload can enhance satiety and reduce overall energy intake at a meal. Current evidence suggests that energy density influences intake through a complex interplay of cognitive, sensory, gastrointestinal, hormonal and neural influences. Other studies that focus on practical applications show how the strategic incorporation of foods lower in energy density into the diet allows people to eat satisfying portions while improving dietary patterns. This review discusses studies that have led to greater understanding of the importance of energy density for food intake regulation and weight management.

Food and the consumer: could labelling be the answer?

Extensive research into the impact of nutrition labelling across Europe has shown that many consumers can effectively use a nutrition label to rank a food for healthiness. The present paper considers observational and laboratory evidence which has examined the impact of nutrition labelling (on food packaging and at point of purchase) on dietary behaviour. In addition, the potential counterproductive effects of foods bearing 'healthy' nutrition labels are examined. The observational evidence provides a useful insight into the key characteristics of nutrition label use. Those most likely to engage with nutrition labels are more likely to have a diet related disease and/or be on a weight loss diet and have a good overall diet quality. Experimental evidence, while limited, suggests that serving size information may be overlooked by consumers. In fact, there may be a tendency among consumers to overeat foods that are perceived to be healthier. The findings from the present paper suggest that if nutrition labelling is to be considered a strategy to facilitate consumers in managing their energy intake, it must coincide with salient, consistent and simple serving size information on the front of food packages and at the point of purchase. There is a clear need for more experimental research using robust methodologies, to examine the impact of nutrition information on dietary intake. In the meantime, there should be greater attention given to portion size within national dietary guidance.

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.

Association of frequent use of food labels with weight loss behaviors among low-income reproductive-age women

OBJECTIVE

To examine whether frequent use of food labels is associated with weight loss behaviors among low-income reproductive-age women.

METHODS

A self-administered survey of 1245 women aged 16 to 40 years assessed the frequency of food label use and weight loss behaviors during the past 12 months. Multivariate logistic regression analyses were performed to examine the association between frequent use of food labels and weight loss behaviors after adjusting for confounders.

RESULTS

Overall, 10.4% to 19.6% of women frequently used food labels to obtain information on different sections (ingredient list, nutrient claims, nutrition panel, serving size, or health claims), dietary components (calories, total fat, saturated fat, cholesterol, sodium/salt, fiber, sugar, vitamins, or minerals), and food products (desserts, snacks, frozen dinners, cereals, salad dressings, table spreads, or raw/processed meat). Women who used food labels frequently were more likely to engage in healthy weight loss behaviors compared to those who used them infrequently or did not use them at all. For example, the odds ratios (OR) and 95% confidence interval (CI) of "began to exercise/exercised more" for the 3 categories of food label use mentioned above were 2.24 and 1.65-3.04; 2.52 and 1.90-3.32; and 1.85 and 1.36-2.52, respectively. The odds of healthy weight loss behaviors were 2 to 4 times higher when food labels were used frequently to seek information on calories and nutrients such as total fat, saturated fat, or cholesterol. However, frequent food label users were also more likely to practice a few unhealthy weight loss behaviors, such as taking diet pills, medicines, herbs, or supplements without a prescription.

CONCLUSIONS

Frequent use of food labels was associated with increased healthy weight loss behaviors among reproductive-age women, which can be incorporated into obesity preventive strategies with distinct awareness regarding unhealthy weight loss behaviors.

Energy density, energy intake, and body weight regulation in adults

The role of dietary energy density (ED) in the regulation of energy intake (EI) is controversial. Methodologically, there is also debate about whether beverages should be included in dietary ED calculations. To address these issues, studies examining the effects of ED on EI or body weight in nonelderly adults were reviewed. Different approaches to calculating dietary ED do not appear to alter the direction of reported relations between ED and body weight. Evidence that lowering dietary ED reduces EI in short-term studies is convincing, but there are currently insufficient data to determine long-term effectiveness for weight loss. The review also identified key barriers to progress in understanding the role of ED in energy regulation, in particular the absence of a standard definition of ED, and the lack of data from multiple long-term clinical trials examining the effectiveness of low-ED diet recommendations for preventing both primary weight gain and weight regain in nonobese individuals. Long-term clinical trials designed to examine the impact of dietary ED on energy regulation, and including multiple ED calculation methods within the same study, are still needed to determine the importance of ED in the regulation of EI and body weight.

Reducing high calorie snack food in young adults: a role for social norms and health based messages

Background

Consumption of high calorie junk foods has increased recently, especially among young adults and higher intake may cause weight gain. There is a need to develop public health approaches to motivate people to reduce their intake of junk food.

Objective

To assess the effect of health and social norm messages on high calorie snack food intake (a type of junk food) as a function of usual intake of junk food.

Design

In a between-subjects design, 129 young adults (45 men and 84 women, mean age = 22.4 years, SD = 4.5) were assigned to one of three conditions: 1) a social norm condition, in which participants saw a message about the junk food eating habits of others; 2) a health condition, in which participants saw a message outlining the health benefits of reducing junk food consumption and; 3) a control condition, in which participants saw a non-food related message. After exposure to the poster messages, participants consumed a snack and the choice and amount of snack food consumed was examined covertly. We also examined whether usual intake of junk food moderated the effect of message type on high calorie snack food intake.

Results

The amount of high calorie snack food consumed was significantly lower in both the health and the social norm message condition compared with the control message condition (36% and 28%, both p < 0.05). There was no significant difference in snack food or energy intake between the health and social norm message conditions. There was no evidence that the effect of the messages depended upon usual consumption of junk food.

Conclusions

Messages about the health effects of junk food and social normative messages about intake of junk food can motivate people to reduce their consumption of high calorie snack food.

Fiber, protein, and lupin-enriched foods: role for improving cardiovascular health

Cardiovascular diseases (CVD) are the leading cause of death globally (World Health Organisation, 2011). Many of the risk factors for CVD are modifiable, including overweight and obesity. Numerous strategies have been proposed to fight CVD, with a special focus being placed on dietary interventions for weight management. The literature suggests that two nutrients, fiber and protein, may play significant roles in weight control and hence cardiovascular health. Increasing both protein and fiber in the diet can be difficult because popular low-carbohydrate and high-protein diets tend to have considerably low-fiber intakes (Slavin, 2005). One approach to obtain both is to develop functional foods using unique ingredients. Lupin flour is a novel food ingredient derived from the endosperm of lupin. It contains 40-45% protein, 25-30% fiber, and negligible sugar and starch (Petterson and Crosbie, 1990). Research conducted to date reveals that lupin-enriched foods, which are naturally high in protein and fiber, may have a significant effect on CVD risk factors. This review explores whether there is a role for fiber-, protein-, and lupin-enriched foods in improving cardiovascular health.

Salad and satiety. The effect of timing of salad consumption on meal energy intake

In a previous study, consuming a fixed amount of low-energy-dense salad as a first course reduced meal energy intake. We investigated whether this effect depended on serving salad before rather than with the main course, or on compulsory rather than ad libitum consumption. On five occasions, 46 women consumed ad libitum a main course of pasta, accompanied four times by low-energy-dense salad (300 g; 100 kcal [418 kJ]). At two meals the salad was served 20 min before the pasta (once compulsory; once ad libitum), and at two meals the salad was served with the pasta (once compulsory; once ad libitum). Results showed that adding a fixed amount of salad to the meal reduced energy intake by 11% (57±19 kcal [238±79 kJ]). Ad libitum salad consumption was less than compulsory consumption and did not significantly affect energy intake. Across all participants, the timing of serving the salad did not significantly influence energy intake, but the effect of timing depended on participant scores for flexible dietary restraint. Consuming low-energy-dense salad before rather than with the main course increased vegetable consumption by 23%. To moderate energy intake, maximizing the amount of salad eaten may be more important than the timing of consumption.

Hidden vegetables: an effective strategy to reduce energy intake and increase vegetable intake in adults

BACKGROUND

The overconsumption of energy-dense foods leads to excessive energy intakes. The substitution of low-energy-dense vegetables for foods higher in energy density can help decrease energy intakes but may be difficult to implement if individuals dislike the taste of vegetables.

OBJECTIVE

We investigated whether incorporating puréed vegetables to decrease the energy density of entrées at multiple meals reduced daily energy intakes and increased daily vegetable intakes.

DESIGN

In this crossover study, 20 men and 21 women ate ad libitum breakfast, lunch, and dinner in the laboratory once a week for 3 wk. Across conditions, entrées at meals varied in energy density from standard versions (100% condition) to reduced versions (85% and 75% conditions) by the covert incorporation of 3 or 4.5 times the amount of puréed vegetables. Entrées were accompanied by unmanipulated side dishes. Participants rated their hunger and fullness before and after meals.

RESULTS

Subjects consumed a consistent weight of foods across conditions of energy density; thus, the daily energy intake significantly decreased by 202 ± 60 kcal in the 85% condition (P < 0.001) and by 357 ± 47 kcal in the 75% condition (P < 0.0001). Daily vegetable consumption significantly increased from 270 ± 17 g of vegetables in the 100% condition to 487 ± 25 g of vegetables in the 75% condition (P < 0.0001). Despite the decreased energy intake, ratings of hunger and fullness did not significantly differ across conditions. Entrées were rated as similar in palatability across conditions.

CONCLUSIONS

Large amounts of puréed vegetables can be incorporated into various foods to decrease the energy density. This strategy can lead to substantial reductions in energy intakes and increases in vegetable intakes. This trial was registered at clinicaltrials.gov as NCT01165086.

Nutrition labels on pre-packaged foods: a systematic review

Objective

To review research on consumer use and understanding of nutrition labels, as well as the impact of labelling on dietary habits.

Design

A systematic review was conducted by searching electronic databases. Relevant articles were screened by two reviewers and included if they met inclusion criteria, including eight methodological criteria. A total of 120 articles were included in the review, including cross-sectional surveys (n96), experimental designs (n17), ‘natural experiments’ (n7) and longitudinal population-based surveys (n2).

Setting

Articles covered seven jurisdictions: USA (n88), Europe (n12), Canada (n9), Australia and New Zealand (n4), Norway (n2), Thailand (n1) and Trinidad (n1).

Subjects

Participants were from a wide range of age groups, socio-economic strata and geographical regions.

Results

Nutrition labels on pre-packaged foods are among the most prominent sources of nutrition information. Nutrition labels are perceived as a highly credible source of information and many consumers use nutrition labels to guide their selection of food products. Evidence also shows a consistent link between the use of nutrition labels and healthier diets. However, the use of labels varies considerably across subgroups, with lower use among children, adolescents and older adults who are obese. Research also highlights challenges in terms of consumer understanding and appropriate use of labelling information.

Conclusions

Nutrition labels on pre-packaged foods are a cost-effective population-level intervention with unparalleled reach. However, to capitalize on their potential, governments will need to explore new formats and different types of information content to ensure that nutrition information is accessible and understandable.

Eating behaviors of children in the context of their family environment

Both a family history of obesity and early childhood obesity have been identified as strong predictors of adult obesity risk. The finding that parental obesity, maternal obesity in particular, increases a child's risk for developing obesity suggests that either shared genes, or environment, or likely a combination of both may promote overeating and excessive weight gain in children. Parents not only create food environments for children's early experiences with food and eating, but they also influence their children's eating by modeling their own eating behaviors, taste preferences, and food choices. Thus, it is important to identify intermediary behavioral eating traits which promote overeating and obesity in children and to determine the extent to which associations between eating traits and excessive weight gain in children may be influenced by genetic factors, environmental factors, or both. Behavioral genetic methods can be used to help partition genetic and environmental sources of variability in behavioral traits. The focus of this paper is to review and discuss findings from both short-term experimental and prospective cohort studies on eating behaviors of children at various stages in their lives. Select child eating traits and parent-child resemblances in eating will be further examined in the context of children's home environment and their familial predisposition to obesity. The paper represents an invited review by a symposium, award winner or keynote speaker at the Society for the Study of Ingestive Behavior [SSIB] Annual Meeting in Portland, July 2009.

Evaluating the impact of menu labeling on food choices and intake

OBJECTIVES

We assessed the impact of restaurant menu calorie labels on food choices and intake.

METHODS

Participants in a study dinner (n=303) were randomly assigned to either (1) a menu without calorie labels (no calorie labels), (2) a menu with calorie labels (calorie labels), or (3) a menu with calorie labels and a label stating the recommended daily caloric intake for an average adult (calorie labels plus information). Food choices and intake during and after the study dinner were measured.

RESULTS

Participants in both calorie label conditions ordered fewer calories than those in the no calorie labels condition. When calorie label conditions were combined, that group consumed 14% fewer calories than the no calorie labels group. Individuals in the calorie labels condition consumed more calories after the study dinner than those in both other conditions. When calories consumed during and after the study dinner were combined, participants in the calorie labels plus information group consumed an average of 250 fewer calories than those in the other groups.

CONCLUSIONS

Calorie labels on restaurant menus impacted food choices and intake; adding a recommended daily caloric requirement label increased this effect, suggesting menu label legislation should require such a label. Future research should evaluate menu labeling's impact on children's food choices and consumption.

Rationale and evidence for menu-labeling legislation

Menu-labeling legislation is a proposed public health intervention for poor diet and obesity that requires chain restaurants to provide nutrition information on menus and menu boards. The restaurant industry has strongly opposed menu-labeling legislation. Using scientific evidence, this paper counters industry arguments against menu labeling by demonstrating that consumers want chain restaurant nutrition information to be disclosed; the current methods of providing nutrition information are inadequate; the expense of providing nutrition information is minimal; the government has the legal right to mandate disclosure of information; consumers have the right to know nutrition information; a lack of information reduces the efficiency of a market economy; and menu labeling has the potential to make a positive public health impact.

Energy density at a buffet-style lunch differs for adolescents born at high and low risk of obesity

The energy density (ED; kcal/g) of foods, when manipulated in the laboratory, affects short-term energy intake. The aim of this study was to examine if, when given a choice, dietary ED (foods only) and energy intake (expressed as a percentage of subjects' estimated daily energy requirement; EER) at a self-selected, single meal differ for teens born with a different familial predisposition to obesity and as a function of their sex. Subjects (13 males, 17 females) were 12years of age and born at high risk (HR; n=15) or low risk (LR; n=15) for obesity based on maternal pre-pregnancy body mass index (BMI; kg/m(2)). The buffet meal, served for lunch and consumed ad libitum, consisted of a variety of foods and beverages with a range in ED. HR subjects consumed a more energy-dense meal (foods only) than LR subjects (1.84 vs. 1.42kcal/g; P=0.02) and males consumed a more energy-dense meal than females (1.83 vs. 1.43kcal/g; P=0.03). Total energy intake, when expressed as a percentage of subjects' daily EER, did not differ between HR and LR subjects (42% vs. 33%; P=0.16). Males, compared to females, consumed ~59% more energy from foods and beverages during the meal (46 vs. 29%; P=0.008). During a single multi-item lunch meal, teens with a familial predisposition to obesity and males, independent of their obesity risk status, self-selected a more energy-dense meal. Familial risk for obesity, through either genetic or environmental pathways, may facilitate a more energy-dense diet.

When, how much and what foods are eaten are related to total daily food intake

Intake in the morning is associated with a reduction in the total intake for the day, while intake at night is associated with greater overall daily intake. These associations are macronutrient specific, with morning carbohydrate intake associated with reduced daily carbohydrate intake, morning fat intake associated with reduced daily fat intake and morning protein intake associated with reduced daily protein intake. Since different types of foods contain differing proportions of macronutrients, the present study investigated the associations of different types of foods ingested at various times of day with total daily and macronutrient intakes. The intakes of 388 male and 621 female free-living individuals reported in 7 d diet diaries were reanalysed. The intakes of twenty-four different types of foods and seven different drinks occurring during the morning (04.00-10.29 hours), afternoon (10.30-16.59 hours) and evening (17.00-02.00 hours) were identified and related to overall daily intakes. Dairy foods, ice cream, beef, other meats, potatoes, pastry, nuts, chips and snacks, condiments, alcohol and soda were significantly associated with higher total intake over the day, while fruit, soup, breakfast cereal, pasta, pizza, water, coffee/tea and diet soda were either not associated or were associated with lower overall intake. Dietary energy density appeared to mediate the associations between particular foods and beverages and overall energy intake. This suggests that eating low-density foods in the morning and avoiding high-density foods at night might aid in reducing overall intake and may be useful in dietary interventions for overweight and obesity.

Does a healthy diet help weight management among overweight and obese people?

A randomized dietary intervention trial across 4 years examined diet, weight, and obesity incidence (body mass index [BMI] > or = 30 kg/m(2)) differences between study groups. Participants were 1,510 breast cancer survivors with BMI > or = 25 kg/m(2) at entry. Dietary intake was assessed yearly by telephone; weight and height were measured at clinic visits. Intervention participants consumed more fruit, vegetables, and fiber and less energy from fat than control participants during follow-up cross-sectionally (p < .0001) and longitudinally (p < .0001); weight did not differ between study groups at any follow-up visit, and significant weight change difference was observed between groups only in the 1st year (p < .0001). Diet and weight results remained unchanged after stratifying by age and BMI. No difference in obesity incidence was found during follow-up (p > .10) among overweight members of either study group. Without specific efforts to reduce total energy intake, dietary modification does not reduce obesity or result in long-term weight loss.

Reducing the energy density of multiple meals decreases the energy intake of preschool-age children

BACKGROUND

The energy density (ED) of an entrée affects children's energy intake at a meal consumed ad libitum. However, the effects in children of changing the ED of meals over multiple days are unknown.

OBJECTIVE

We aimed to test the effect of reducing the ED of multiple meals on the ad libitum energy intake of preschool-age children over 2 d.

DESIGN

In this crossover study, 3- to 5-y-old children (n = 10 boys, 16 girls) were served manipulated breakfasts, lunches, and afternoon snacks 2 d/wk for 2 wk. Foods and beverages served at these meals during 1 wk were lower in ED than were those served during the other week. ED reductions were achieved by decreasing fat and sugar and by increasing fruit and vegetables. Dinner and an evening snack were sent home with children, but these meals did not vary in ED. The same 2-d menu was served in both conditions.

RESULTS

Children consumed a consistent weight of foods and beverages over 2 d in both conditions, and therefore their energy consumption declined by 389 +/- 72 kcal (14%) in the lower-ED condition, a significant decrease (P < 0.0001). Differences in energy intake were significant at breakfast on day 1, and they accumulated at manipulated meals over 2 d (P < 0.01). Intake of the nonmanipulated meals was similar between conditions.

CONCLUSIONS

Children's energy intake is influenced by the ED of foods and beverages served over multiple days. These results strengthen the evidence that reducing the ED of the diet is an effective strategy for moderating children's energy intake.

Daily food intake in relation to dietary energy density in the free-living environment: a prospective analysis of children born at different risk of obesity

BACKGROUND

Young children adjust their short-term intake in response to variations in energy density (ED; kcal/g) from preloads in laboratory studies. It remains unknown whether this compensation also occurs under free-living conditions.

OBJECTIVE

The aims of the study were to test whether children aged 3-6 y regulate their habitual daily food (g) and energy (kcal) intakes in relation to ED and whether compensation differs for children born at different risk of obesity.

DESIGN

Participants were children born at high risk (n=22) or low risk (n=27) of obesity on the basis of maternal prepregnancy body mass index (BMI; in kg/m(2)). Daily ED, food intake, and energy intake were assessed from 3-d food records that either included or excluded beverages. Intake regulation was explored by relating children's daily food and energy intakes to ED and, more importantly, by examining residual scores derived by regressing daily food intake on ED.

RESULTS

For both risk groups, daily food intake was inversely correlated with ED (P < 0.05), whereas daily energy intake was not significantly correlated with ED at most ages (P>0.05). In analyses that excluded beverages, mean residual scores significantly increased from 3 to 6 y of age in high-risk children, which indicates relative overconsumption, but decreased in low-risk children, which indicates relative underconsumption (risk group x time interaction, P=0.005).

CONCLUSIONS

Children adjusted their daily food intake in relation to ED, which suggests caloric compensation under free-living conditions. Compensation ability may deteriorate with age in a manner that favors relative food overconsumption among obesity-prone children.

Dietary energy density increases during early childhood irrespective of familial predisposition to obesity: results from a prospective cohort study

OBJECTIVE

This study compared 4-year changes in daily energy density (ED; kcal/g) in children born at different risk for obesity, characterized the stability of ED and examined associations between ED and child body composition.

DESIGN

Prospective cohort study to measure habitual dietary ED of children who are born at different risk for obesity.

SUBJECTS

Children who were born at high risk (n=22) or low risk (n=27) for obesity based on maternal pre-pregnancy weight.

MEASUREMENTS

Three-day food records were collected from children's mothers at child ages 3, 4, 5 and 6 years. Three categories of ED were computed (food only, food and milk, and food and all beverages) and body composition assessed at each year.

RESULTS

The mean (+/-s.e.m.) ED increased over time across all children (linear trend: P<0.003): 2.18+/-0.07 to 2.32+/-0.06 kcal/g (food only); 1.66+/-0.07 to 1.82+/-0.06 kcal/g (food and milk); and 1.24+/-0.04 to 1.37+/-0.05 kcal/g (food and all beverages). Intraindividual coefficients of variation were smaller than those previously reported for adults. Weight indices were not correlated with dietary ED (P>0.05).

CONCLUSION

Dietary ED increased in young children, irrespective of their predisposition to obesity, between the ages of 3 and 6 years. The genes that promote childhood obesity may not exert their influence through dietary ED, which may be more strongly influenced by environmental factors.

Stomach filling may mediate the influence of dietary energy density on the food intake of free-living humans

The energy density of the diet has been demonstrated to be a significant influence on the daily intakes of humans which has led to the hypothesis that intake control is based upon the weight and volume of food and not its energy content. The study explored the roles of the components used in the calculation of energy density and stomach filling in dietary energy density effects upon intake. Dietary energy density relationships with intake and body size were studied in 264 male and 406 female free-living adult humans who provided a detailed record of their eating and drinking in 7-day diaries. High energy density was associated with larger amounts of food energy and larger amounts of solids, but lower total weight of meals, daily intakes, and weekly intakes. The lower total weight occurred due to lower fluid intake in drinks. Multiple regression analysis revealed that overall dietary energy density was more important than the energy density of particular nutrients. Intake of fluids in drinks did not contribute to the relationship of dietary energy density with intake. The estimated weight of the contents of the stomach following the meals was relatively constant regardless of the energy density of the meals, daily, or weekly intakes. Energy density was not significantly related with body size, height, weight, or BMI. The findings support the notion that short-term intake is controlled on the basis of its weight and volume as opposed to its food energy content.

Position of the American Dietetic association: fat replacers

It is the position of the American Dietetic Association that the majority of fat replacers, when used in moderation by adults, can be safe and useful adjuncts to lowering the fat content of foods and may play a role in decreasing total dietary energy and fat intake. Moderate use of low-calorie, reduced-fat foods, combined with low total energy intake, could potentially promote dietary intake consistent with the objectives of Healthy People 2010 and the 2005 Dietary Guidelines for Americans . The obesity epidemic in the nation has been attributed to energy imbalance, mainly because of increased food consumption and/or sedentary lifestyle, or both. Evidence suggests that lowering total energy intake along with a reduction in total fat intake can have a substantial impact on body weight and risk of chronic diseases. Fat replacers are used to provide some or all of the functional properties of fat, while providing fewer calories than the fat being replaced, and are used in a variety of products, from baked goods to frozen desserts. Fat replacers can be effective only if they lower the total caloric content of the food and if the consumer uses these foods as part of a balanced meal plan. Consumers should not be led to believe that fat- and calorie-reduced products can be consumed in unlimited amounts. Fat replacers are most useful when they help with calorie control and when their use encourages the consumption of foods delivering important nutrients.

Dietary Energy Density and Body Weight: Is There a Relationship?

The energy density of foods and beverages is defined as the available energy per unit weight (kJ/g). Energy density of the diet is usually calculated excluding non-caloric beverages and drinking water. Because water contributes more to the weight of foods than any macronutrient, energy-dense foods are not necessarily those high in sugar or fat, but those that are dry. Evidence linking dietary energy density with body weight is critically evaluated in this review. Existing reports of a positive association between dietary energy density, higher energy intakes, and weight gain are based on laboratory and clinical studies. Although some cross-sectional epidemiological studies have linked dietary energy density with higher body mass index (BMI) values, the data are not consistent. At this time, there are no longitudinal cohort data linking dietary energy density with higher obesity risk.

Pros and cons of proposed interventions to promote healthy eating

The increased prevalence and costs associated with the obesity epidemic have made preventive efforts a public health priority. Public health has historically relied on a series of targeted regulations, taxes, and education efforts to curb epidemics, and will rely on similar strategies to combat obesity. We argue that interventions targeted at youth are relatively easy to justify on economic grounds due to the additional protections that this group requires, but that justification for government interventions aimed at curbing obesity among adults requires additional evidence that private markets are not functioning properly. We then present seven proposed intervention strategies to promote healthy eating, and use an economic framework to discuss the relative merits of the interventions. This evaluation will allow policymakers to make more informed decisions concerning the relative merits of these strategies in combating the obesity epidemic.

Energy density and portion size: their independent and combined effects on energy intake

The energy density (kcal/g) and the portion size (g) of foods have been identified as two properties of foods that can modulate energy intake. Recent studies have shown that when either the energy density or the portion size of foods is increased, energy intake increases. Within a meal, when both factors are increased simultaneously, their effects are independent and add together to increase energy intake. On the other hand, reducing the energy density of a first course, while increasing the volume that is consumed, leads to a decrease in energy intake at the entire meal. The mechanisms by which both factors exert their influence are not well understood but likely include cognitive and orosensory factors as well as physiological controls related to gastric distention and gastric emptying. Findings from studies in this area of research provide evidence that the energy density and the portion size of foods are important determinants of energy intake. An environment in which the food supply is ample and large portions of energy-dense foods are readily available to consumers can contribute to an overconsumption of calories.

Combined effects of energy density and portion size on energy intake in women

BACKGROUND

Increases in both the portion size and energy density of food have both been shown to increase energy intake, but the combined effects of such increases have not been investigated.

OBJECTIVE

The objective was to determine the combined effects of energy density and portion size on energy intake in women.

DESIGN

This study used a within-subjects design. Once a week for 6 wk, 39 women were served breakfast, lunch, and dinner ad libitum. The main entrée at lunch was formulated in 2 versions that varied in energy density (5.23 or 7.32 kJ/g), each of which was served in 3 different portion sizes (500, 700, or 900 g). The 2 versions were matched for macronutrient composition and palatability. Breakfast and dinner were standard meals.

RESULTS

Increases in portion size and energy density led to independent and additive increases in energy intake (P <0.0001). Subjects consumed 56% more energy (925 kJ) when served the largest portion of the higher energy-dense entrée than when served the smallest portion of the lower energy-dense entrée. Subjects did not compensate for the additional intake by eating less at the subsequent meal. Despite substantial differences in energy intake, no systematic differences in ratings of hunger and fullness across conditions were observed.

CONCLUSIONS

The energy density and the portion size of a food act independently to affect energy intake. The findings indicate that large portions of foods with a high energy density may facilitate the overconsumption of energy.

Diet and obesity

PURPOSE OF REVIEW

Obesity continues to increase in the United States and worldwide. There is controversy surrounding different dietary patterns used to promote weight loss, and none has emerged as clearly more effective. This paper briefly reviews the factors that influence energy intake and dietary treatments used to promote weight loss.

RECENT FINDINGS

Increasing portion size, eating away from home, and consuming a variety of high-energy dense foods appear to increase energy intake. Hormonal influences on diet continue to be explored. Very-low-calorie diets and low-carbohydrate diets lead to greater initial weight loss, but long-term results are no better than more moderate calorie-restricted diets. A program using meal replacements appears to lead to weight loss slightly greater than calorie-restricted diets and offers one option to treat obesity. Dietary patterns low in energy density and glycemic index have potential in treating obesity and should be studied further.

SUMMARY

Clearly, a dietary pattern that prescribes a lower total energy intake is necessary for weight loss, and this pattern should be sustainable to maintain weight loss. Although many dietary programs can achieve short-term loss of weight, dietary treatment should be recommended that emphasizes lifestyle changes and is consistent with other dietary guidelines to promote long-term health. Features consistent with this are a dietary pattern low in total calories, saturated fat, and refined carbohydrate; moderate in whole grains; and high in low-energy dense vegetables and fruits. Future studies should explore dietary strategies and combination therapies that contribute to weight loss, long-term weight maintenance, and improved health.

Dietary energy density is associated with increased intake in free-living humans

Dietary energy density markedly influences the daily dietary intake of humans. The present study examined the relation of energy density to dietary intake and body size in 371 male and 581 female adults. The subjects were free-living and provided a detailed record of their everyday food and drink intake in 7-d food diaries. The reported diets were analyzed for the relation of energy density to body size and to per-meal, daily, and weekly dietary intake. High energy density was associated with greater (P < 0.001) total intake, especially of fat, when intake was correlated with energy density (r = 0.26, P < 0.001) and when the daily intake of individual participants was correlated with their daily dietary density (r = 0.66, P < 0.001). These results occurred regardless of sex, low reporting, or the inclusion of drinks in the energy density calculations. High energy density was also associated with a high rate of intake (r = 0.46, P < 0.001) and large meal sizes (r = 0.61, P < 0.001). However, energy density was not correlated with body size, height, weight, or body mass index. High energy density appears to be related to greater overall intake in the short-term, but there may be compensation over the long term, with no net effect on body size.

What Can Intervention Studies Tell Us about the Relationship between Fruit and Vegetable Consumption and Weight Management?

Given the recent surge in obesity, effective dietary strategies for weight management are required. Because fruits and vegetables are high in water and fiber, incorporating them in the diet can reduce energy density, promote satiety, and decrease energy intake. Although few interventions have specifically addressed fruit and vegetable consumption, evidence suggests that coupling advice to increase intake of these foods with advice to decrease energy intake is a particularly effective strategy for weight management. This approach may facilitate weight loss because it emphasizes positive messages rather than negative, restrictive messages.

The Supersizing of America: Portion Size and the Obesity Epidemic

Although we are just beginning to understand how environmental factors such as portion size affect eating behavior, the available data suggest that large portions of energy-dense foods are contributing to the obesity epidemic. Several possible strategies for adjusting portions to bring intake back in line with energy requirements are discussed. The continuing rise in the rates of obesity calls for urgent action.