Fenfluramine suppresses snack intake among carbohydrate cravers but not among noncarbohydrate cravers

Two groups of obese individuals who consume excessive calories primarily as snack foods have been distinguished: carbohydrate cravers and noncarbohydrate cravers. Both groups consume about 800 calories from snacks (860 kcal vs 879 kcal) and about 2000 calories from meals (1906 kcal vs 2080 kcal) daily. The carbohydrate-cravers consume almost all of their snacks as carbohydrate-rich foods (7 ± 0.4 CHO snacks/day vs 0.9 ± 0.12 protein snacks/day) whereas the noncarbohydrate cravers consume approximately equal numbers of protein and carbohydrate snacks (4.5 ± 0.6 carbohydrate snacks/day vs 3.5 ± 0.5 protein snacks/day). D-fenfluramine significantly reduced the intakes of calories (range 24–44%) and carbohydrates (range 28–41%) from snacks among the carbohydrate cravers over a three month treatment period. The drug did not affect snack intake by the noncarbohydrate cravers until the third month of treatment when the consumption of both types of snacks decreased significantly. D-fenfluramine decreased mealtime carbohydrate intake among the carbohydrate cravers throughout the treatment period (range 16–23%); mealtime protein intake declined comparably (range 14–18%) during the first and third treatment months. The drug had no effect on mealtime carbohydrate nor protein intake by noncarbohydrate cravers.     

Mood and carbohydrate cravings

The relationship between mood and carbohydrate cravings, and the possible role of gender in these associations, was investigated in a sample of 113 males and 138 female college students. Participants completed a Cravings Questionnaire and several mood inventories (profile of mood states, Beck Depression Inventory, and the Vitality Inventory) in groups of 25. Individuals classifying themselves as "carbohydrate cravers" reported foods rich in carbohydrates, and "protein cravers" reported protein-rich foods as being the ones they most strongly craved. Carbohydrate cravers reported feeling distressed prior to their cravings and satisfied, happy/good and relaxed following carbohydrate consumption. Protein cravers reported feeling anxious or hungry prior to their cravings and happy, normal, bored, and energetic following protein-rich food consumption. A non-significant correlation existed between "protein" cravers' ratings of craving intensity and mood, but a significant positive correlation existed between "carbohydrate" cravers' ratings of craving intensity and almost all mood scales assessed for both male and female "carbohydrate" cravers. The correlation between craving intensity and mood existed predominately with individuals who craved sweet carbohydrate-rich foods.     

The involvement of brain serotonin in excessive carbohydrate snacking by obese carbohydrate cravers

A specific hunger for carbohydrate-rich foods has been observed in animals and human beings and appears to be regulated by the brain neurotransmitter serotonin. Consumption of a carbohydrate-rich meal increases the synthesis and release of brain serotonin (by enhancing the brain uptake of its precursor, tryptophan). As a consequence of this increased release of serotonin, carbohydrate intake is decreased at the next meal. Consumption of protein does not increase brain serotonin levels or decrease carbohydrate intake. A subgroup of obese individuals who consume carbohydrate-rich snack foods at specific times of day or evening has been identified. Such individuals do not routinely snack on protein-rich foods, and their consumption of calories and nutrients at meals is not excessive. Evidence is presented that carbohydrate snacking seems to be related to a "need" to increase the level of brain serotonin; treatment with a drug, d-1 fenfluramine, that increases serotoninergic neurotransmission significantly decreases carbohydrate snack consumption. Weight loss among the population of carbohydrate cravers might be most successful if treatment includes either a diet or drugs that increase brain serotonin activity when the need to snack on carbohydrate is most likely to occur.     

Carbohydrate craving in obese people: Suppression by treatments affecting serotoninergic transmission

We examined the existence of carbohydrate cravings, and the effects on such cravings of treatments that enhance serotonin release, among 24 obese subjects who claimed to have excessive appetites for carbohydrates. Subjects living in a college dormitory for four weeks were given three fixed meals daily and allowed to choose at will among five protein-rich or five carbohydrate-rich isocaloric snack foods, provided via a vending machine. For two weeks, they received no treatment (study 1) or a placebo (study 2); for the next two weeks, they received placebo, d-1 fenfluramine or 1-tryptophan. All but one of the subjects exhibited a marked preference for carbohydrate-rich over protein-rich snacks during the first two weeks of the study. The average daily intake of carbohydrate-rich snacks was 4.1 ± 0.4 and of protein-rich snacks 0.8 ± 0.3. Seventeen of the subjects failed to consume any protein snacks on most days during the baseline or test periods, thus it was not possible for us to examine the effect of test treatments on protein snack intake. Fenfluramine administration significantly reduced carbohydrate snacking in six of nine test subjects, as well as in the group as a whole (2.4 ± 0.6 snacks/day vs 4.2 ± 0.6 during the two-week baseline period). Tryptophan significantly diminished carbohydrate intake in three of the eight treated subjects, and increased it in one subject; it did not significantly modify snacking patterns in the group as a whole. Placebo administration did not affect carbohydrate intake in any of the seven test subjects. These observations show that some obese people do consume carbohydrate-rich snacks frequently and preferentially, and that this behavior can sometimes be diminished by treatments thought to enhance serotonin's release (fenfluramine) or synthesis (tryptophan).     

Carbohydrate craving: a double-blind, placebo-controlled test of the self-medication hypothesis

Carbohydrate craving, the overwhelming desire to consume carbohydrate-rich foods in an attempt to improve mood, remains a scientifically controversial construct. We tested whether carbohydrate preference and mood enhancement could be demonstrated in a double-blind, placebo-controlled self-administration trial. Overweight females who met strict operational criteria for carbohydrate craving participated in two 3-day discrete choice trials over a 2-week period. Participants reported their mood before and at several time points after undergoing a dysphoric mood induction and ingesting, either a carbohydrate beverage or a taste and calorie-matched protein-rich balanced nutrient beverage. Every third testing day, participants were asked to self-administer the beverage they preferred based on its previous mood effect. Results showed that, when rendered mildly dysphoric, carbohydrate cravers chose the carbohydrate beverage significantly more often than the protein-rich beverage and reported that carbohydrate produced greater mood improvement. The carbohydrate beverage was perceived as being more palatable by the carbohydrate cravers, although not by independent taste testers who performed the pre-trial taste matching. This study, performed under rigorous study conditions, supports the existence of a carbohydrate craving syndrome in which carbohydrate self-administration improves mildly dysphoric mood.     

d-Fenfluramine selectively suppresses carbohydrate snacking by obese subjects

Twenty obese inpatients who claimed to crave carbohydrate-rich foods were given d-fenfluramine (15 mg p.o., twice daily) or its placebo, double-blind, for two consecutive eight-day periods. Food choices were measured on treatment days 1, 7, and 8 by giving the subjects access to unlimited portions of six isocaloric meal foods (three high in carbohydrate and three high in protein) and of 10 isocaloric snack foods (five high in protein and five high in carbohydrate) available 24 hours a day in a computerized vending machine. d-fenfluramine reduced mealtime calorie intake by only 16% (from 1940 +/- 94 to 1630 +/- 92; p < .001), mealtime carbohydrate by 22%, and had no significant effect on mealtime protein consumption; in contrast, snack calorie intake was reduced by 41% (from 707 +/- 97 to 414 +/- 46; p < .001), and snack carbohydrate intake by the same proportion. The mean number of carbohydrate-rich snacks consumed per day decreased from 5.8 +/- 0.8 to 3.4 +/- 0.4 (p < .01), while that of protein-rich snacks failed to change signficantly (i.e., from 0.7 +/- 0.2 to 0.5 +/- 0.2).     

Gender differences in the relation between food cravings and mood in an adult community: Results from the fleurbaix laventie ville santé study.

OBJECTIVE: The aim of this survey was to study food cravings and its indulgence in community adults (538 women and 506 men) and to compare nutritional parameters, weight preoccupations, and weight history between cravers and noncravers. METHOD: Cravers experienced a strong urge to eat specific foods more than once a week during the past 6 months. Food intake was estimated by a 3-day food record. RESULTS: 28% of women and 13% of men were food cravers. Cravers, especially women, were more frequently concerned about their weight than noncravers. Energy intake during snacks was higher in cravers. Less than 40% of cravers reported being hungry when they experienced cravings. Women cravers indulged their cravings as often as men. They reported more frequently negative feelings, whereas men reported more frequently positive feelings. DISCUSSION: This study shows that food craving episodes are strongly associated with mood but in a different way in women and men.     

Response style and vulnerability to anger-induced eating in obese adults

Emotional eating appears to contribute to weight gain, but the characteristics that make one vulnerable to emotional eating remain unclear. The present study examined whether two negative affect response styles, rumination and distraction, influenced palatable food intake following an anger mood induction in normal weight and obese adults. We hypothesized that higher rumination and lower distraction would be associated with greater vulnerability to anger-induced eating, particularly among obese individuals. Sixty-one participants (74% female, mean age=34.6) underwent neutral and anger mood inductions in counterbalanced order. Directly following each mood induction, participants were provided with 2400 kcal of highly palatable snack foods in the context of a laboratory taste test. Results revealed that distraction influenced energy intake following the mood induction for obese but not normal weight individuals. Obese participants who reported greater use of distraction strategies consumed fewer calories than those reporting less use of distraction strategies. These findings were independent of subjective hunger levels, individual differences in mood responses and trait anger, and other factors. Rumination did not account for changes in energy intake among obese or normal weight participants. Among obese individuals, the tendency to utilize fewer negative affect distraction strategies appears to be associated with vulnerability to eating in response to anger. Future research should determine whether coping skills training can reduce emotional eating tendencies.     

Trait anxiety, but not trait anger, predisposes obese individuals to emotional eating

The present study examined whether trait anxiety and trait anger are associated with vulnerability to emotional eating, particularly among obese individuals. Lean (n = 37) and obese (n = 24) participants engaged in a laboratory study where they completed measures of trait anxiety and trait anger at screening and then completed 3 counterbalanced experimental sessions involving different mood inductions (neutral, anxiety, anger). Following each mood induction, participants were provided with snack foods in a sham taste test. Models predicting snack intake revealed a significant trait anxiety×body mass index group interaction, such that high trait anxiety was positively associated with food intake for obese individuals, but not their lean counterparts. Contrary to the hypothesis, trait anger was not associated with food intake for obese or lean participants. Results suggest that trait anxiety may be a risk factor for emotional eating among obese individuals.     

Shape of snack foods does not predict snack intake in a sample of preschoolers: a cross-over study

ABSTRACT: BACKGROUND: In the past decade, the proportion snacking has increased. Snack foods consumed are predominantly not nutritious foods. One potential venue to increase children's diet quality is to offer healthy snack foods and we explored if shaped snack foods would lead to increased consumption. METHODS: We investigated the consumption of high-fiber snacks (banana bread, pancakes, and sandwiches) served either in normal (round, square) or shaped (heart, hands, animals) form to preschoolers 2-5 years old attending a local child care center (n=21). The 9 weeks long, prospective, cross-over intervention study was designed to expose each child repeatedly to each snack in each shape (4 times per snack). Snacks were served as morning or afternoon snack and caretakers' reports were used to account for the child's consumption of a meal preceding the study snack (breakfast or lunch). RESULTS: There was no significant difference in snack consumption between the shaped and normal snacks. However, the mean energy intake from snacks was significantly greater for Caucasian children compared with Asian children. Further, Asian children consumed much less banana bread than the other two snacks. Overall, children who had not eaten breakfast or lunch prior to the morning or afternoon snack ate significantly more calories from the snacks (84.1 kcal, p-value<0.0001). CONCLUSION: Findings of this study confirm previous research that the shape of the foods does not affect snack consumption in children. However, we also report two unexpected findings: a) the strong interaction between ethnicity and snack consumption and b) that Asian children consumed much less banana bread than Caucasian children. The role of children's ethnic background profoundly affects snack preference and must be considered in the study of children's eating behaviors and in interventions to promote healthy eating habits.     

The emotional eating scale. Can a self-report measure predict observed emotional eating?

We assessed the validity of the emotional eating scale (EES) by examining whether the EES predicted food intake following two negative mood inductions. Participants underwent mood inductions for anxiety, anger and neutral mood, then received snack foods in a sham palatability test. EES anxiety, but not anger, predicted intake. Participants high on EES anxiety consumed more snacks during the anxiety mood induction, whereas participants low on EES anxiety consumed less snacks. Results suggest that EES anxiety is a predictor of anxiety-driven eating and may be used to assess emotional eating when direct observation of intake is not possible.     

Postprandial glucose and insulin responses to various snacks of equivalent carbohydrate content in normal subjects

To evaluate glucose and insulin responses after ingestion of snacks, we gave healthy, nondiabetic male subjects carbohydrate equivalent (25 g) snacks or isocaloric (265 kcal) snack meals in a random crossover design. Individual snacks composed of either a milk chocolate bar, granola bar, chocolate milk, peanut butter cups, yogurt, or potato chips produced similar glucose response curves. Plasma glucose concentrations were lower (p less than or equal to 0.05) at 30 and 60 min postprandially than after a corresponding oral glucose challenge. In contrast, insulin responses to the snacks exhibited a two-fold variation in peak values. Isocaloric snack meals of cereal-milk, cheese sandwich-milk, and peanut butter sandwich-chocolate milk produced glucose and insulin responses similar to individual snacks. Although glucose concentrations at 60 min fell somewhat below baseline values after each snack, clinical hypoglycemia was not evident. These data clearly indicate a similarity in glycemic response among normal individuals consuming a variety of common snacks.     

Comparison of high-fat and high-carbohydrate foods in a meal or snack on short-term fat and energy intakes in obese women

The present study aimed to compare the action of high-fat and high-carbohydrate (CHO) foods on meal size (satiation) and post-meal satiety in obese women. A within-subjects design was used; each participant received all four nutritional challenges. Fifteen healthy obese women (age 21-56 years, BMI 35-48 kg/m2) participated; thirteen completed all four test days. On two test days, participants were exposed to a nutritional challenge comprising an ad libitum high-fat or high-CHO lunch. On the other two test days they were exposed to a challenge comprising an ad libitum sweet high-fat or high-CHO mid-afternoon snack. Energy and macronutrient intakes were measured at each eating episode. Visual analogue rating scales were completed periodically to record subjective feelings of appetite. When offered a high-CHO selection of foods at lunch and mid-afternoon participants consumed less energy than when offered a high-fat selection. However, post-meal satiety was similar. Total test-day energy intake was significantly higher when high-fat foods were consumed at lunch, but not as a snack. Consumption of high-fat foods at a lunch and snack increased the amount of fat consumed over the whole test day. In conclusion, energy intake of an eating episode was influenced by nutrient composition in this group of obese women. Consumption of high-fat foods at lunch or as a snack led to overconsumption relative to high-CHO foods. However, high-fat foods at meals may have greater potential to influence daily intake than at snacks, probably because meals are larger eating episodes and therefore give greater opportunity to overconsume.     

成都市学龄儿童零食行为研究

目的了解成都市学龄儿童零食行为现状,为指导儿童合理消费零食提供依据。方法整群抽取成都市城区2所小学四～六年级学生1290名,对近6个月的零食行为进行问卷调查。结果近6个月以来调查对象吃零食频率在3次/d以内者达93.4%;最常吃的零食为水果(54.1%),冰激凌(35.3%),糖果、巧克力(28.2%);选择高糖高脂高盐零食者达93.7%;在非饥饿状态下吃零食的比例为69.0%,因饥饿而吃零食的比例为31.0%;选择零食的依据主要是味道(83.4%)、营养(52.2%)、父母准备(17.7%)和家人常吃(15.0%);吃零食的时间依次为晚餐前(53.3%)、晚餐后(28.7%)和晚上睡觉前(9.2%);零食来源主要是自己购买(54.3%)和父母准备(43.5%)。结论成都市学龄儿童零食行为仍存在一定问题,亟待引导和改善。     

Isocaloric meal and snack foods differentially affect eating behavior

The present study tested whether foods categorized as meals reduce subsequent intake more than isocaloric foods categorized as snacks. The study was repeated three times with variations. In each variation we manipulated whether subjects received meal or snack foods in an isocaloric load. In Variation 1, subjects consumed less following a load of meal foods than snacks. Variation 2 found this effect to be short-term, affecting food choice 20 min following a load but not 3 h later. Variation 3 demonstrated: (1) this effect occurs independent of the effects of the weights of foods, and (2) this effect varies specifically with subject perceptions of foods (i.e. whether they are part of a meal or snack). These results are discussed in terms of how cognitive representations of preload foods can influence subsequent consumption.     

Storing Empty Calories and Chronic Disease Risk: Snack-Food Products,Nutritive Content,and Manufacturers in Philadelphia Corner Stores

Corner stores are part of the urban food environment that may contribute to obesity and diet-related diseases, particularly for low-income and minority children. The snack foods available in corner stores may be a particularly important aspect of an urban child’s food environment. Unfortunately, there is little data on exactly what snack foods corner stores stock, or where these foods come from. We evaluated snack foods in 17 Philadelphia corner stores, located in three ethnically distinct, low-income school neighborhoods. We recorded the manufacturer, calories, fat, sugar, and sodium for all snack items, excluding candy and prepared foods. We then compared the nutritive content of assessed snack items to established dietary recommendations and a school nutrition standard. In total, stores stocked 452 kinds of snacks, with only 15% of items common between all three neighborhoods. Total and unique snacks and snack food manufacturers varied by neighborhood, but distributions in snack type varied negligibly: overall, there were no fruit snacks, no vegetable snacks, and only 3.6% of all snacks (by liberal definition) were whole grain. The remainder (96.4% of snacks) was highly processed foods. Five of 65 manufacturers supplied 73.4% of all kinds of snack foods. Depending on serving size definition, 80.0-91.5% of snack foods were “unhealthy” (by the school nutrition standard), including seven of 11 wholegrain products. A single snack item could supply 6-14% of a day’s recommended calories, fat, sugar, and sodium on average (or 56-169% at the extreme) for a “typical” child. We conclude that corner store snack food inventories are almost entirely unhealthful, and we discuss possible implications and next steps for research and intervention.     

Evidence for diminished brain 5-hydroxytryptamine biosynthesis in obese diabetic and non-diabetic humans

Obese persons are often reported to have marked cravings for simple carbohydrate-rich foods. Because of the proposed relationships between protein/carbohydrate selection, plasma tryptophan (TRP) to large neutral amino acids (LNAA) ratios, and brain 5-hydroxytryptamine (5-HT) neurotransmission, we examined the plasma TRP/LNAA ratios in four categories of obese subjects, before and 120 min after oral glucose tolerance test (GTT). Plasma TRP/LNAA ratios were reduced in obese, non-diabetics by 18%, the same extent as for older (approximately 52 yr old) nonobese subjects. In more advanced obesity, ie obesity associated either with glucose intolerance, hyperinsulinemia or hypoinsulinemia, plasma TRP/LNAA ratios were reduced by 25%. One hundred twenty minutes after a 100 g glucose load plasma TRP/LNAA had not been normalized. Based on animal data, these results suggest there may be diminished 5-HT neurotransmission in obese diabetics. The implications of these findings for the cravings of obese for carbohydrate-rich foods is discussed.     

Meal-induced changes in tryptophan:LNAA ratio: effects on craving and binge eating

This study investigated the effects of meals varying in macronutrient composition on plasma tryptophan/large neutral amino acid (tryp:LNAA) ratios and subsequent appetite and mood in women defined as "food cravers." Nine women consumed one of each of a high protein, high carbohydrate and mixed meal on three separate days. Blood samples and appetite and mood ratings were taken before and at intervals up to 150 min after meal consumption. The first subsequent ad libitum food intake was recorded in diaries. The tryp:LNAA ratio increased significantly after the carbohydrate meal compared to protein and mixed meals. No significant correlations between change in tryp:LNAA ratio and mood or macronutrient intake at the ad libitum eating episode were observed. There was a negative correlation between tryp:LNAA ratio and desire to binge eat (p=0.03) and a trend towards a negative correlation between tryp:LNAA ratio and craving for carbohydrate-rich foods (p=0.07). Participants whose ad libitum eating episode was categorized as a binge had a trend (p=0.06) toward lower plasma tryp:LNAA ratio than those who did not binge. Regression analysis showed that the effects of change in tryp:LNAA ratio on desire to binge eat was independent of meal type and changes in insulin and glucose concentrations. These findings suggest that reducing plasma tryp:LNAA ratio, via consumption of a protein-rich meal, may mediate the desire to binge eat in susceptible women.     

Nutrient intakes and snacking frequency in female students

Background: Snacking can have the negative image of being detrimental to the diet, because snack foods are commonly thought of as providing only 'empty calories'—high in energy but low in micronutrients. This observational study looked at the nutrient density of snacks and meals, and at the effect of eating frequency on mean daily nutrient intakes in 44 female students (aged 17–26 years). Methods: Baseline dietary data from an existing intervention study were re-analysed. Eating occasions, taken from 7-day weighed food diaries, were classified as meals or snacks by time of day, and the composition of meals and snacks compared. Subjects were divided into tertiles by eating frequency and their nutrient intakes compared. Results: As eating frequency increased, the number of snacks and the number of different snack items in the diet increased, while the number of meals remained constant. Snacks, overall, were significantly lower in percentage non-alcohol energy from fat and higher in percentage non-alcohol energy from carbohydrate. Snacks had lower nutrient densities than meals for non-starch polysaccharide (NSP), minerals and vitamins except vitamin C. However, there were no significant differences between the top and bottom tertiles of snacking frequency for overall percentage energy from fat, protein or carbohydrate, or intakes of micro-nutrients. The top tertile tended to be leaner and have higher energy intakes than infrequent eaters (not significant). There was a significant negative correlation between eating frequency and body mass index (BMI). Conclusions: It is concluded that snacking per se did not compromise diet quality in this group, and that those with a high snacking frequency were eating more in general and choosing a wider variety of foods, resulting in a balanced intake of nutrients.