Determinants of appetite ratings: the role of age, gender, BMI, physical activity, smoking habits, and diet/weight concern.

BACKGROUND: Appetite measures are often recorded by visual analogue scales (VAS), and are assumed to reflect central nervous system (CNS) perceptions and sensations. However, little is known about how physiological, psychological, social, and cultural factors influence VAS. OBJECTIVE: To investigate whether age, gender, body mass index (BMI), smoking habits, physical activity, diet behaviour, and menstruation cycle are determinants of appetite ratings. DESIGN: We investigated appetite ratings in different groups of a population during a single meal test, including 178 healthy women (98) and men (80), aged 20-60 years with a BMI of 18.5-35.0 kg/m(2). Subjects consumed an evening meal composed to meet individual requirements of energy content and recommendations regarding macronutrient composition. Before and every half hour until 3 hours after the meal, subjects filled out VAS for satiety, fullness, hunger, and prospective food intake. They also filled in a questionnaire on eating/slimming behaviour. RESULTS: Multiple linear regression analyses showed that gender and age were the most powerful predictors of postprandial satiety (p<0.001, adj. R(2)=0.19) and hunger (p<0.001, adj. R(2)=0.15). Repeated measures general linear model (GLM) analyses revealed that women felt more satisfied than men (p<0.001) and older subjects felt more satisfied than younger (p<0.01). Furthermore, light/no exercisers felt more satisfied and less hungry than hard/moderate exercisers (p<0.05), but these differences disappeared after adjusting for age and gender. Smokers rated their prospective consumption lower than non-smokers (p<005) and women in the ovulation phase felt less hungry than women in the menstruation phase (p<005). Neither BMI nor diet/weight concern were significantly associated with appetite ratings. CONCLUSIONS: Appetite ratings differed according to age, gender, and physical activity and to a lesser degree for smoking habits and menstruation cycle. Appetite ratings were not influenced by BMI and diet/weight concern. These factors should be considered when planning studies and analysing data concerning appetite sensations.

Video game playing increases food intake in adolescents: a randomized crossover study.

BACKGROUND: Video game playing has been linked to obesity in many observational studies. However, the influence of this sedentary activity on food intake is unknown. OBJECTIVE: The objective was to examine the acute effects of sedentary video game play on various components of energy balance. DESIGN: With the use of a randomized crossover design, 22 healthy, normal-weight, male adolescents (mean ± SD age: 16.7 ± 1.1 y) completed two 1-h experimental conditions, namely video game play and rest in a sitting position, followed by an ad libitum lunch. The endpoints were spontaneous food intake, energy expenditure, stress markers, appetite sensations, and profiles of appetite-related hormones. RESULTS: Heart rate, systolic and diastolic blood pressures, sympathetic tone, and mental workload were significantly higher during the video game play condition than during the resting condition (P < 0.05). Although energy expenditure was significantly higher during video game play than during rest (mean increase over resting: 89 kJ; P < 0.01), ad libitum energy intake after video game play exceeded that measured after rest by 335 kJ (P < 0.05). A daily energy surplus of 682 kJ (163 kcal) over resting (P < 0.01) was observed in the video game play condition. The increase in food intake associated with video game play was observed without increased sensations of hunger and was not compensated for during the rest of the day. Finally, the profiles of glucose, insulin, cortisol, and ghrelin did not suggest an up-regulation of appetite during the video game play condition. CONCLUSION: A single session of video game play in healthy male adolescents is associated with an increased food intake, regardless of appetite sensations. The trial was registered at clinicaltrials.gov as NCT01013246.

Comparison of 150-mm versus 100-mm visual analogue scales in free living adult subjects.

The aim of this study was to verify whether appetite sensation scores obtained from 150-mm visual analogue scales (VAS) can be compared to those obtained from 100-mm scales. On one occasion, using a within-subject design, 25 participants (mean age: 42.2 + or - 13.3 years, mean body mass index: 22.9 + or - 2.3 kg/m(2)) recorded their appetite sensations before lunch, and at five additional time points during the postprandial period. At each time point, both VAS (150 mm and 100 mm) were used to record desire to eat, hunger, fullness, satiety, and prospective food consumption. The VAS in the same booklet were completed immediately one after the other in a randomized order to eliminate the order effect. We observed that the immediate, successive completion of questionnaires varying in length resulted in no significant difference in appetite markers, with a strong linear relationship between the two tools (r from 0.80 to 0.98, P<0.01). We conclude that VAS scores obtained from 150-mm to 100-mm length scales are interchangeable, both before and in response to a meal.

Effect of moderate intakes of different tea catechins and caffeine on acute measures of energy metabolism under sedentary conditions.

Green tea may stimulate energy metabolism; however, it is unclear if acute effects are caused by specific catechins, caffeine or their combination. The objective of the present study was to examine the separate and combined effects of different catechins and caffeine on energy expenditure (EE) and fat oxidation over a single day. Fifteen healthy, normal-weight males received capsules containing placebo, caffeine alone (150 mg), or caffeine plus a catechin mixture (600 mg) enriched in either epigallocatechin-3-gallate (EGCG), epigallocatechin or a mix of catechins, in a randomised cross-over double-blinded design. On each test day EE, respiratory quotient (RQ) and substrate oxidation were measured under sedentary conditions in a respiratory chamber for 13.5 h. We found no significant treatment effect on EE (P = 0.20) or RQ (P = 0.68). EGCG with caffeine insignificantly raised EE and fat oxidation v. caffeine-only and placebo (EE 5.71 (SE 0.12) v. 5.68 (SE 0.14) v. 5.59 (SE 0.13) MJ/12.5 h, respectively; fat oxidation 84.8 (SE 5.2) v. 80.7 (SE 4.7) v. 76.8 (SE 4.0) g/12.5 h). Catechin/caffeine combinations at these dosages and mode of application had non-significant acute effects on EE and fat oxidation. The maximum observed effect on EE of about 2 % could still be meaningful for energy balance over much longer period of exposure. However, higher short-term effects reported in the literature may reflect variations in green tea extracts, added caffeine, or synergies with physical activity. The specific mechanisms and conditions that may underpin observed longer-term benefits of catechin-enriched green tea consumption on body composition remain to be confirmed.

Reproducibility and power of ad libitum energy intake assessed by repeated single meals.

BACKGROUND: The reproducibility of the measurement of ad libitum energy intake (EI) is not well known. Furthermore, it is not known whether standardized conditions before the test day influence this measure. OBJECTIVE: The objective was to examine the reproducibility and power of the measurement of ad libitum EI with and without prior diet standardization. DESIGN: Fifty-five healthy, normal-weight men were tested in 2 groups, one with (D, n = 32) and one without (ND, n = 23) prior diet standardization, on 2 different identical occasions. They were given a standardized energy-fixed breakfast and then an ad libitum lunch 4.5 h later. Reproducibility was assessed by the coefficient of repeatability. RESULTS: No effect of prior diet standardization was seen on the reproducibility of ad libitum EI (P = 0.56), but diet standardization increased ad libitum EI significantly (P < 0.001). The correlation between ad libitum EI on the 2 test days was r = 0.861 (R(2) = 0.742, P < 0.0001) and r = 0.654 (R(2) = 0.428, P < 0.001) in the D and ND groups, respectively. The coefficient of repeatability and CV were 1478 kJ and 8.9% compared with 1831 kJ and 14.5% in the D and ND groups, respectively. A paired design with a study power of 0.8 requires 17 and 26 subjects, with and without prior diet standardization, respectively, to detect a difference of 500 kJ in EI. CONCLUSIONS: The ad libitum test meal used to measure spontaneous EI is reproducible, and the reproducibility does not seem to be influenced by prior standardization. However, prior diet standardization exerts a significant effect on ad libitum EI.

Associations between postprandial insulin and blood glucose responses, appetite sensations and energy intake in normal weight and overweight individuals: a meta-analysis of test meal studies.

It is unclear whether postprandial blood glucose or insulin exerts a regulatory function in short-term appetite regulation in humans. The aim of this study was to investigate, by use of meta-analysis, the role of blood glucose and insulin in short-term appetite sensation and energy intake (EI) in normal weight and overweight participants. Data from seven test meal studies were used, including 136 healthy participants (ALL) (92 normal weight (NW) and 44 overweight or obese (OW)). All meals were served as breakfasts after an overnight fast, and appetite sensations and blood samples were obtained frequently in the postprandial period. Finally, an ad libitum lunch was served. Data were analysed by fixed effects study level (SL) meta-regression analysis and individual participant data (IPD) regression analysis, using STATA software. In SL analysis, postprandial insulin response was associated with decreased hunger in ALL, NW and OW (P < 0.019), and with increased satiety in NW (P = 0.004) and lower subsequent EI in OW (P = 0.022). Multivariate IPD analysis showed similar associations, but only in NW for hunger, satiety and EI (P < 0.028), and in ALL for EI (P = 0.016). The only association involving blood glucose was the multivariate IPD analysis showing an inverse association between blood glucose and EI in ALL (P = 0.032). Our results suggest that insulin, but not glucose, is associated with short-term appetite regulation in healthy participants, but the relationship is disrupted in the overweight and obese. We conclude that the postprandial insulin response may be an important satiety signal, and that central nervous system insulin resistance in overweight might explain the blunted effect on appetite.