Effect Of Portion Size Research Articles

Super-size me: Portion size effects on young children's eating

Large portions of energy-dense foods are believed to favor obesity-promoting eating behaviors in young children. The following review presents evidence on food portion size effects on children's eating behavior and eating regulation, with comparison of findings to adult studies of portion size. Individual differences in children's susceptibility to portion size, particularly associations with weight status, are addressed. Finally, potential mechanisms of effects and strategies to offset the intake promoting effects of portion size are considered.

Effects of portion size and energy density on young children's intake at a meal

Background: Large portions of energy-dense foods are one feature of obesity-promoting dietary environments. Entrée portion size has been shown to influence energy intake at meals by young children. The role of energy density (ED) in children's response to portion size, however, is unknown.Objective: We aimed to test the effects of portion size and ED on children's food and energy intakes at a meal.Design: Participants were 53 (28 girls and 25 boys; 15 Hispanic, 20 black, 16 white, 2 other race) 5- to 6-y-old children [mean (±SD) body mass index percentile: = 61 ± 28]. A 2 × 2 within-subjects design was used to manipulate entrée portion size (250 compared with 500 g) and ED (1.3 compared with 1.8 kcal/g). Fixed portions of other familiar foods were provided. Weighed intake, food preference, and weight and height data were obtained.Results: Effects of portion size (P < 0.0001) and ED (P < 0.0001) on entrée energy intake were independent but additive. Energy intake from other foods at the meal did not vary across conditions. Compared with the reference portion size and ED condition, children consumed 76% more energy from the entrée and 34% more energy at the meal when served the larger, more energy-dense entrée. Effects did not vary by sex, age, entrée preference, or body mass index z score.Conclusions: These findings provide new evidence that portion size and ED act additively to promote energy intake at meals among preschool-aged children.

The Effect of Large Portion Sizes on Energy Intake Is Sustained for 11 Days

A previous study showed that increasing the portion sizes of all foods led to an increase in energy intake that was sustained over 2 days. The objective of the present study was to determine whether participants would compensate for excess energy intake or continue to overeat when portion sizes were increased for 11 days. Participants in the study were 23 normal-weight and overweight participants (10 women and 13 men). All of their foods and caloric beverages were provided during two different periods of 11 consecutive days, which were separated by a 2-week interval. During one period, standard portions of all items were served; during the other, all portion sizes were increased by 50%. The 50% increase in portion sizes resulted in a mean increase in daily energy intake of 423 +/- 27 kcal (p < 0.0001), which did not differ significantly between women and men. This increase was sustained for 11 days and did not decline significantly over time, leading to a mean cumulative increase in intake of 4636 +/- 532 kcal. A significant effect of portion size on intake was seen at all meals and in all categories of foods except fruit (as a snack) and vegetables. The effect of portion size on intake was not influenced by the body weight status of participants. These results strengthen the evidence suggesting that increased portions contribute to the overconsumption of energy and to excess body weight.

Effects of portion size on chronic energy intake

BackgroundThis study experimentally examined the effects of repeated exposure to different meal portion sizes on energy intake.MethodsNineteen employees of a county medical center were given free box lunches for two months, one month each of 1528 and 767 average kcal. Foods were identical in the two conditions, but differed in portion size. Meals averaged 44% calories from fat. Participants self-reported how much of each lunch was eaten. Unannounced 24-hour dietary recalls were also conducted by phone twice per week during each exposure period.ResultsMean energy intake at the lunch meal was 332 kcal/day higher in large lunch than in small lunch periods (p < .001). Mean 24-hour energy intake was 278 kcal/day higher in large versus small lunch periods (p < .001). There was no evidence of compensation over time. Average weight change over the month of large and small lunches was 0.64 ± 1.16 kg and 0.06 ± 1.03 kg, respectively, about what would be expected with the observed differences in energy intake.ConclusionThis study suggests that chronic exposure to large portion size meals can result in sustained increases in energy intake and may contribute to body weight increases over time.

Larger Portion Sizes Lead to a Sustained Increase in Energy Intake Over 2 Days

Objective We tested the effect on energy intake of increasing the portion size of all foods and beverages served over 2 consecutive days. Design The study used a randomized crossover design. Subjects/setting Subjects were 32 adults from a university community. Intervention For 2 consecutive days in each of 3 weeks, subjects ate their main meals in a controlled setting and were given snacks for consumption between meals. We used the same two daily menus each week, but varied the portion sizes of all foods and beverages served in a given week (either 100%, 150%, or 200% of baseline amounts). Main Outcome Measures Energy intake and ratings of hunger and satiety were measured. Statistical Analyses Performed A linear mixed model with repeated measures was used. Results There was a significant effect of portion size on energy intake in both men and women ( P<0.0001). Increasing portions by 50% increased daily energy intake by 16% (women: 335 kcal/day; men: 504 kcal/day), and increasing portions by 100% increased intake by 26% (women: 530 kcal/day; men: 812 kcal/day). Energy intake did not differ between the 2 days of each week. Daily ratings of fullness were lowest in the 100% portion condition ( P=0.0004), but did not differ significantly in the 150% and 200% conditions. Conclusions Increasing the portion size of all foods resulted in a significant increase in energy intake that was sustained over 2 days. These data support suggestions that large portions are associated with excess energy intake that could contribute to increased body weight.

Reductions in portion size and energy density of foods are additive and lead to sustained decreases in energy intake

When the portion size and energy density (in kcal/g) of a food are varied simultaneously in a single meal, each influences energy intake independently. We aimed to determine how the effects of portion size and energy density combine to influence energy intake and satiety over multiple meals for 2 d. In a crossover design, 24 young women were provided with meals and snacks for 2 consecutive days per week for 4 wk; all foods were consumed ad libitum. Across the 4 sessions, the subjects were served the same 2 daily menus, but all foods were varied in portion size and energy density between a standard level (100%) and a reduced level (75%). Reducing the portion size and energy density of all foods led to significant and independent decreases in energy intake over 2 d (P < 0.0001). A 25% decrease in portion size led to a 10% decrease in energy intake (231 kcal/d), and a 25% decrease in energy density led to a 24% decrease in energy intake (575 kcal/d). The effects on energy intake were additive and were sustained from meal to meal. Despite the large variation in energy intake, there were no significant differences in the ratings of hunger and fullness across conditions over the 2 d. Reductions in portion size and energy density independently decreased ad libitum energy intake in women when commonly consumed foods were served over 2 d. Reductions in both portion size and energy density can help to moderate energy intake without increased hunger.

Relationship between Portion Size and Energy Intake among Infants and Toddlers: Evidence of Self-Regulation

Objectives To assess whether dietary intakes of infants and young toddlers show evidence of energy self-regulation. Design Data from 24-hour recalls collected in the 2002 Feeding Infants and Toddlers Study were analyzed. Multivariate regressions were used to explore the relationship between portion size and usual energy intake as well as the relationship between portion size, number of eating occasions, number of unique foods, and energy density. Subjects/Setting A national random sample of 3,022 US infants and toddlers 4 to 24 months of age. Statistical Analyses Performed To measure variability in portion size, an average portion size z score was computed for each child in the sample, across 45 different food groups. The number of eating occasions was defined as the total number of times a child had anything to eat or drink during the day, excluding eating occasions that included only water and/or supplements. The total number of unique foods in a day was defined as the number of unique food codes included in the 24-hour recall, and energy density was computed as kilocalories/gram, including all foods, beverages, and water. Linear regression models were used to assess the effect of portion size and other self-regulation mechanisms on energy intake and to assess the effect of these self-regulation mechanisms on portion size. Separate analyses were performed for three age groups: 4 to 5 months, 6 to 11 months, and 12 to 24 months. Results A significant negative association was found for all age groups between the number of eating occasions and average portion size z scores, indicating that children who eat less often during the day consume larger-than-average-portion sizes and children who eat more often during the day consume smaller-than-average portions. For infants (11 months and younger), a significant negative association was noted between energy density and average portion size z scores, indicating that, as the energy density of the diet goes down, infants consume larger-than-average portions and, as the energy density of the diet goes up, they consume smaller-than-average portions. Among infants 6 to 11 months, there was a significant positive relationship between portion size and the number of unique foods consumed. For toddlers, there was no association between average portion size z scores and energy density, suggesting that energy self-regulation mechanisms are diminished in this age group. Conclusions Our findings confirm the presence of energy self-regulation among infants and young toddlers. These findings can be used to assure parents and caregivers that infants have an innate ability to regulate energy intake. At the same time, it is important to educate parents and caregivers about the potential for environmental cues to diminish natural hunger-driven eating behaviors, even among young toddlers. Dietetics professionals should emphasize the potential adverse effects that coercive feeding behaviors can have on children’s innate ability to regulate energy intake. This includes not only admonitions to “clean your plate,” but overrestriction of intake that may be motivated by concerns that children are overeating.

Effects on hunger and satiety, perceived portion size and pleasantness of taste of varying the portion size of foods: A brief review of selected studies

The portion size of foods has been identified as an important environmental factor known to affect short-term energy intake. Experiments that were conducted both in the free-living environment and in laboratory-based settings to investigate the effects of portion size on energy intake unanimously showed that as the portion size of food increased, so did subjects' energy intake. Despite the fact that the profound effects of portion size on energy intake are well documented, the mechanisms by which portion size affects energy intake are poorly understood. There is some evidence that sensory influences (e.g. visual and olfactory cues), cognitive factors (e.g. learning, social norms, monetary considerations), and post-ingestive consequences (e.g. sensations of hunger and fullness) related to the portion size of foods may interact to affect the amount of food that is consumed during a meal.

Effect of feed portion size on growth of rainbow trout, Oncorhynchus mykiss (Walbaum), reared at different temperatures

Groups of 125 rainbow trout, Oncorhynchus mykiss (Walbaum) were fed identical daily feed rations using various portion sizes (0.23–4.29 pellets fish − 1 portion − 1 ). The procedure was repeated for rearing temperatures of 5 °C, 10 °C, and 15 °C. Throughout the study, growth rates and feed conversion ratios (FCR) were best when a portion size of 0.52 pellets per fish was used. As temperature increased, good growth rates and FCR were observed over a broader range of portion sizes (0.52–3.11 pellets per fish) than previously seen at 5 °C, indicating a high level of plasticity in the trout's ability to adjust to different portion sizes at higher temperatures. This study suggests that the temperature of the water should be considered when feed portion sizes are decided upon as the rate at which trout are able to catch pellets appears to be influenced by temperature.

The influence of food portion size and energy density on energy intake: implications for weight management

The increase in the prevalence of obesity has coincided with an increase in portion sizes of foods both inside and outside the home, suggesting that larger portions may play a role in the obesity epidemic. Although it will be difficult to establish a causal relationship between increasing portion size and obesity, data indicate that portion size does influence energy intake. Several well-controlled, laboratory-based studies have shown that providing older children and adults with larger food portions can lead to significant increases in energy intake. This effect has been demonstrated for snacks and a variety of single meals and shown to persist over a 2-d period. Despite increases in intake, individuals presented with large portions generally do not report or respond to increased levels of fullness, suggesting that hunger and satiety signals are ignored or overridden. One strategy to address the effect of portion size is decreasing the energy density (kilojoules per gram; kilocalories per gram) of foods. Several studies have demonstrated that eating low-energy-dense foods (such as fruits, vegetables, and soups) maintains satiety while reducing energy intake. In a clinical trial, advising individuals to eat portions of low-energy-dense foods was a more successful weight loss strategy than fat reduction coupled with restriction of portion sizes. Eating satisfying portions of low-energy-dense foods can help to enhance satiety and control hunger while restricting energy intake for weight management.

The influence of food portion size and energy density on energy intake: implications for weight management

The increase in the prevalence of obesity has coincided with an increase in portion sizes of foods both inside and outside the home, suggesting that larger portions may play a role in the obesity epidemic. Although it will be difficult to establish a causal relationship between increasing portion size and obesity, data indicate that portion size does influence energy intake. Several well-controlled, laboratory-based studies have shown that providing older children and adults with larger food portions can lead to significant increases in energy intake. This effect has been demonstrated for snacks and a variety of single meals and shown to persist over a 2-d period. Despite increases in intake, individuals presented with large portions generally do not report or respond to increased levels of fullness, suggesting that hunger and satiety signals are ignored or overridden. One strategy to address the effect of portion size is decreasing the energy density (kilojoules per gram; kilocalories per gram) of foods. Several studies have demonstrated that eating low-energy-dense foods (such as fruits, vegetables, and soups) maintains satiety while reducing energy intake. In a clinical trial, advising individuals to eat portions of low-energy-dense foods was a more successful weight loss strategy than fat reduction coupled with restriction of portion sizes. Eating satisfying portions of low-energy-dense foods can help to enhance satiety and control hunger while restricting energy intake for weight management.

Portion Sizes and the Obesity Epidemic ,

The rise in obesity rates over the past 30 y has been paralleled by increases in the portion size of many foods and the prevalence of eating away from home. Foods of particular concern are those that have a high energy density (kJ/g). Many well-controlled, laboratory-based studies have found that large portions of energy-dense foods can lead to excess energy intakes. This influence of large portions on energy intake has been supported by data collected in naturalistic settings. Further research is needed to explore strategies that can be used to moderate the effects of portion size on food consumption. One promising strategy is to reduce the energy density of foods, while maintaining food weight or volume, so that consumers can eat satisfying portions while reducing their energy intakes. There is a need for effective educational messages that not only emphasize limiting the consumption of foods high in energy density, but also encourage the consumption of those with a low energy density, such as fruits and vegetables. The delivery of consistent messages will require more cooperation among the food and restaurant industries, policy makers, and scientists. Effective strategies will also require consumers to understand and accept the importance of eating reasonable portions for better health.

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

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

Portion size of food affects energy intake in normal-weight and overweight men and women

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. 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. Fifty-one men and women were served lunch 1 d/wk for 4 wk. Lunch included an entrée of macaroni and cheese consumed ad libitum. At each meal, subjects were presented with 1 of 4 portions of the entrée: 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. 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. 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.

EFFECT OF FOODSERVICE COOKERY METHOD, MARINATION, PORTION SIZE, AND ENDPOINT COOKING TEMPERATURE ON COOKING CHARACTERISTICS AND TENDERNESS OF PORK LOIN CHOPS1

There is an increased use of rapid cookery systems (e.g. Clamshell®) in the foodservice sector to decrease preparation time. Foodservice pork loin chops (n=320) were used to determine the effects of cookery method (Clamshell®, CS vs Farberware, FB), marination (marinated vs nonmarinated), portion size (113 vs 170 g), and endpoint cooking temperature (68 vs 75C) on cooking characteristics, shear force values and sensory traits. The first experiment (n = 160 chops) evaluated Warner-Bratzler shear force, while the second experiment (n = 160 chops) measured sensory traits and both measured cooking characteristics. The chops cooked by CS had shorter (P 0.05). Marination increased (P < 0.05) thaw loss. Cook times were shorter (P < 0.01) and thaw and cook losses were lower (P < 0.05) for 113 g compared to 170 g chops. The 113 g portions were more (P < 0.05) tender and juicy than 170 g. Chops cooked to 68C required less (P < 0.05) cooking time, and had lower (P < 0.05) cook losses than chops cooked to 75C. Marinated 113 g chops were significantly juicier than any other combination of marination and portion size. These data suggest that a rapid cookery system can reduce cooking time of foodservice pork loin chops by as much as 50%, without detrimental effects on eating quality.

QUALITY GRADE, PORTION SIZE, NEEDLE TENDERIZATION AND COOKERY METHOD EFFECTS ON COOKING CHARACTERISTICS AND PALATABILITY TRAITS OF PORTIONED STRIP LOIN AND TOP SIRLOIN STEAKS

Strip Loin (IMP # 1180A) and Top Sirloin Center Cut steaks (IMP # 1184B) purchased from a foodservice purveyor and aged 21 days were used to evaluate cookery method, needle tenderization, quality grade and portion size effects on palatability and cooking characteristics. Both steak types were distributed across 4 quality grade classes (USDA Select = S, USDA Choice = C, USDA Prime = P, and Certified Angus BeefTM= UC), 2 portion sizes (strip loins, 283 and 397 g; top sirloins, 255 and 340 g), 2 tenderization treatments (needle tenderized = T and nontenderized = NT) and 2 cooking methods (Clamshell® broiler-grill = CS and electric grill = FW). Cook time/100 g was lower (P 0.05) sensory tenderness in the strips or sirloin steaks. Sensory tenderness scores were lower (P 0.05) sensory tenderness in the strips steaks but improved sensory tenderness scores in the sirloin steaks. A needle tenderization by quality class interaction in the sirloins showed that T steaks from the S, C and UC classes were more tender than NT steaks; however, tenderization did not affect tenderness of P steaks. Collectively these data suggest that rapid cookery systems (i.e., Clamshell®) can reduce cooking time in portioned foodservice strip and top sirloin steaks without detrimental effects on palatability.