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Background: Whether large portion sizes affect children's eating behavior has rarely been studied. Objectives: Our objectives were 1) to determine the effects of repeated exposure to a large portion of an entree on preschoolaged children's awareness of portion size, self-selected portion size, and food intake and 2) to evaluate associations of children's responsiveness to portion size with weight status and overeating. Design: Energy intake, bite size, and comments about portion size were evaluated among 30 children at 2 series of lunches in which either an age-appropriate portion or a large portion of an entree was served. On separate occasions, the children's self-served portions, weight, height, and tendency to overeat were assessed. Results: Doubling an age-appropriate portion of an entree increased entree and total energy intakes at lunch by 25% and 15%, respectively. Changes were attributable to increases in the average size of the children's bites of the entree without compensatory decreases in the intake of other foods served at the meal. These increases were seen even though observational data indicated that the children were largely unaware of changes in portion size. Greater responsiveness to portion size was associated with higher levels of overeating. The children consumed 25% less of the entree when allowed to serve themselves than when served a large entree portion. Conclusions: Large entree portions may constitute an 'obesigenic' environmental influence for preschool-aged children by producing excessive intake at meals. Children with satiety deficits may be most susceptible to large portions. Allowing children to select their own portion size may circumvent the effects of exposure to large portions on children's eating. Am J Clin Nutr 2003:77:1164-70. KEY WORDS Portion size, children's eating behavior, food intake, preschool-aged children

Background: Large portions of food may contribute to excess energy intake and greater obesity. However, data on the effects of portion size on food intake in adults are limited. Objectives: We examined the effect of portion size on intake during a single meal. We also investigated whether the response to portion size depended on which person, the subject or the experimenter, determined the amount of food on the plate. Design: Fifty-one men and women were served lunch 1 d/wk for 4 wk. Lunch included an entree of macaroni and cheese consumed ad libitum. At each meal, subjects were presented with 1 of 4 portions of the entree: 500, 625,750, or 1000 g. One group of subjects received the portion on a plate, and a second group received it in a serving dish and took the amount they desired on their plates. Results: Portion size significantly influenced energy intake at lunch (P < 0.0001). Subjects consumed 30% more energy (676 kJ) when offered the largest portion than when offered the smallest portion. The response to the variations in portion size was not influenced by who determined the amount of food on the plate or by subject characteristics such as sex, body mass index, or scores for dietary restraint or disinhibition. Conclusions: Larger portions led to greater energy intake regardless of serving method and subject characteristics. Portion size is a modifiable determinant of energy intake that should be addressed in connection with the prevention and treatment of obesity. KEY WORDS Portion size, serving size, serving method, energy intake, food intake, obesity, adults

This study investigated the effect on fat and energy intakes of fat-free potato chips made with olestra compared with regular potato chips. Ninety-five participants (unrestrained and restrained males and females) were tested in 2 conditions. In the information condition, participants were given nutrition information about the chips and were aware that the chips differed in fat and energy contents. In the no-information condition, participants were not aware of the differences. In both conditions, participants ate either regular or fat-free potato chips ad libitum for an afternoon snack in a crossover design in two 10-d periods. To assess 24-h intake, participants completed food diaries twice in each 10-d period. The results showed that all groups significantly reduced their fat and energy intakes in the snack when eating the fat-free chips compared with the regular chips (P [is less than] 0.0001). Also, potato chip intake did not differ across time for either type of chip. Over 24 h all participants had lower fat intakes (P [is less than] 0.05) when eating the fat-free potato chips compared with the regular chips, but 24-h energy intake was not significantly different between groups. When information was provided, restrained participants ate more of the fat-free chips than the regular chips; however, this increase did not negate the reductions in fat and energy associated with eating the fat-free chips. This study showed that substituting fat-free (olestra-containing) potato chips for regular-fat chips can help reduce fat and energy intakes in short-term (within meal) situations and reduce fat intake over 24 h. Am J Clin Nutr 1998;68:282-90.

This study tested the hypothesis that the amount (weight or volume) of food consumed affects the satiating potency of a food, independent of its energy content. Normal-weight young men (n = 20) were tested in a within-subjects design. Subjects were served a milk-based drink or no drink (control), followed 30 min later by a self-selected lunch and [is greater than] 4 h later by a self-selected dinner. Milk drinks were equal in energy content (2088 kJ, or 499 kcal) and had similar proportions of fat (30.3%). carbohydrate (54.7%). and protein (15%) across three volumes: 300, 450, and 600 mL. Ratings of palatability, sensory properties, and energy content of the drinks and of hunger completed before consumption of the preloads were not significantly different among conditions. The results showed that preload volume affected energy intake at lunch (P [is less than or equal to] 0.009) such that energy intake was less after the 600-mL preload than after the 300-mL preload. This effect was still present when energy intake at dinner was included (P [is less than or equal to] 0.022). At lunch, including energy from the preload, subjects overate relative to the control condition (4323 [+ or -] 322 kJ) after the 300- (5263 [+ or -] 321 kJ) and 450-mL (5011 [+ or -] 300 kJ) preloads but not after the 600-mL (4703 [+ or -] 353 kJ) preload. Thus, the best adjustment for the energy in the preloads was with the largest, least energy-dense drink. Consistent with the effects on intake, the volume of the drinks affected ratings of hunger and fullness. These results indicate that the volume consumed is an important determinant of satiety after milk drinks under these conditions. Ant J Clin Nutr 1998; 67:1170-77.

This study examined the effect of energy density, independent of fat content and palatability, on food and energy intakes. With use of a within-subjects design, normal-weight women (n = 18) were provided with meals for 2 d during each of three test sessions. During lunch, dinner, and an evening snack, subjects were given free access to a main entree varying in energy density (low, medium, or high). The manipulated main entrees were similar in palatability to their counterparts across conditions. Low-energy compulsory (consumption required) side dishes accompanied each meal. Subjects also consumed a standard, compulsory breakfast. Results showed that subjects consumed a similar amount of food (by weight) across the three conditions of energy density. Thus, significantly more energy was consumed in the condition of high energy density (7532 [+ or -] 363 kJ, or 1800 [+ or -] 86 kcal) than in the medium- (6356 [+ or -] 281 kJ, or 1519 [+ or -] 67 kcal) and low- (5756 [+ or -] 178 kJ, or 1376 [+ or -] 43 kcal) energy-density conditions (P [is less than] 0.0001). There were no differences in hunger or fullness before meals, after meals, or over the 2 d across conditions. The results from this study indicate that energy density affects energy intake independent of macronutrient content or palatability, suggesting that the overconsumption of high-fat foods may be due to their high energy density rather than to their fat content. Am J Clin Nutr 1998;67:412-20.

Many reduced-fat foods retain the sensory properties of their high-fat counterparts through the use of fat substitutes. This study examined whether regulation of energy intake is affected when the nonabsorbable fat substitute olestra is used to uncouple the sensory properties of fat from fat absorption and metabolism. Cream of broccoli soups were developed in three versions: fat-free, fat-free + olestra (33.3 g olestra), and high-fat (33.3 g fat) (923 900 and 2150 kJ per serving, respectively). The olestra soup had the nutrient composition of the fat-free soup but the sensory properties of the high-fat soup. Subjects were grouped by sex, body weight, and dietary restraint (total n = 67). Subjects had either no preload (control) or a soup preload (465 g) followed by a self-selection lunch. Intake was measured at lunch, dinner, snack, and breakfast. At lunch, the response to the soup preloads was not affected by sex, dietary restraint, or body weight. Energy intake (soup + lunch) was significantly greater in the high-fat than in the control condition (P [is less than] 0.05), but energy intake in the fat-free, olestra, and high-fat soup conditions, was not significantly different from that in the control condition (3570, 3352, and 4457 kJ in control, fat-free, olestra, and high-fat soup condition, respectively), Thus, subjects compensated completely for the energy in the fat-free and olestra soups but not for the energy in the high-fat soup. No differences were found in the response to the two fat-free conditions, one with the fatty taste and one without. In this study the sensory properties of fat alone, ie, apart from the physiologic affects of fat, did not affect energy regulation.

The macronutrient composition of the diet can influence hunger, satiety, food intake, body weight, and body composition. Fat, not carbohydrate, is the macronutrient associated with overeating and obesity. Fat is overeaten because it is highly palatable and because it provides a high level of energy in a given volume of food. However, when given in equal volumes, carbohydrate (sugar) and fat have similar effects on hunger, satiety, and subsequent food intake when infused intragastrically or ingested in foods by normal-weight, unrestrained young men. In obese and restrained subjects, preloads of high-carbohydrate yogurts suppress subsequent food intake more than do high-fat yogurts, indicating a relative insensitivity to the satiety value of fat. Both the amount of fat in the diet and total energy intake should be managed in weight-loss regimens. Low-fat foods and fat substitutes can help to reduce fat intake. Although more data are required, currently the best dietary advice for weight maintenance and for controlling hunger is to consume a low-fat, high-carbohydrate diet with a high fiber content. Am J Clin Nutr 1995; 61(suppl):960S-7S.

Lean healthy males received either parenteral or enteral infusions of pure fat or carbohydrate (2092 kJ), or isotonic saline, to determine their influences on food intake and energy regulation in self-selected lunch and dinner meals. In the first study, six males received intravenous infusions for 3.5 h in the morning, followed by lunch 30 min after the infusion ended and dinner 6 h later. No compensation was seen for energy differences in intravenous infusions. In the second study, six males received intragastric infusions for 15 min or 3.5 h. Rapid intragastric infusions of fat or carbohydrate and slow infusions of fat significantly reduced intake at lunch, whereas slow carbohydrate infusions did not. In both studies, subjects reduced intake at lunch 30 min after 2092-kJ yogurt preloads varying in fat and carbohydrate, demonstrating their ability to respond to orally derived energy. These results support the existence of mechanisms in the gastrointestinal tract for the rapid detection of the energy content of ingested nutrients or foods in lean males. Am J Clin Nutr 1995;61:754-64.

Food intake, food selection, macronutrientintake, sensory-specific satiety, and ratings of hunger and satiety were measured after high- and low-energy salad preloads (2414 kJ, or 172 kJ) or no preload to determine whether patients with eating disorders compensate appropriately for different energy intakes. Subjects were female patients with a DSM-III-R diagnosis of anorexia nervosa with bulimic features or bulimia nervosa. or non patient, normal- weight, nondieters (n = 9/group).At a self-selected lunch 30 min after the preloads, all of the groups reduced intake after the high-energy preload, with the bulimics showing the best compensation. The anorexics chose low-energy foods and in some conditions ate a smaller proportion of fat than did the other groups. The bulimics ate more high-energy foods was than did the anorexics. The anorexics demonstrated sensory-specific satiety only after the high-energy salad and the bulimics only after the low- energy salad. Overall, these data suggest that while many of their responses to food are abnormal,patients with eating disorders have some capacity to respond to physiological hunger and satiety cues. Am J Clin Nutr1992;55:1093-1103.