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Increased gluconeogenesis (GNG) has been suggested to contribute to protein-induced satiety via modulation of glucose homoeostasis. The objective was to determine GNG and appetite in healthy human subjects after a high-protein v. a normal-protein diet and to assess whether GNG contributes to protein-induced satiety. A total of twenty-two healthy subjects (ten men and twelve women: age 23 (sem 1) years, BMI 22·1 (sem 0·5) kg/m2) received an isoenergetic high-protein (30/0/70 % of energy from protein/carbohydrate/fat) or normal-protein diet (12/55/33 % of energy from protein/carbohydrate/fat) for 1·5 d in a randomised cross-over design. Appetite ratings were measured using visual analogue scales (VAS); endogenous glucose production and GNG were measured via infusion of [6,6-2H2]glucose and ingestion of 2H2O. Moreover, fasting glucose and [beta]-hydroxybutyrate concentrations were measured. Glycogen stores were lowered at the start with a glycogen-lowering exercise test. During the high-protein compared with the normal-protein diet, GNG was increased and appetite was suppressed (GNG: 148 (sem 7) v. 133 (sem 6) g/24 h, P < 0·05; and 24 h area under the curve for hunger: 694 (sem 46) v. 1055 (sem 52) mm VAS x 24 h, P < 0·001; fullness: 806 (sem 59) v. 668 (sem 64) mm VAS x 24 h, P < 0·05; desire to eat: 762 (sem 48) v. 1004 (sem 66) mm VAS x 24 h, P < 0·001). There was no correlation between appetite ratings and GNG. Glucose concentration was lower (4·09 (sem 0·10) v. 4·89 (sem 0·06) mmol/l, P < 0·001) and [beta]-hydroxybutyrate concentration was higher (1349 (sem 139) v. 234 (sem 25) [mu]mol/l, P < 0·001) after the high-protein compared with the normal-protein diet. In conclusion, after a high-protein diet, GNG was increased and appetite was lower compared with a normal-protein diet; however, these were unrelated to each other. An increased concentration of [beta]-hydroxybutyrate may have contributed to appetite suppression on the high-protein diet. [ABSTRACT FROM AUTHOR]

BACKGROUND & AIMS: Growth hormone (GH) affects body composition by a relatively reduced fat mass and increased fat free mass. The intake of protein as well as the specific amino acids arginine and lysine potently stimulate GH secretion. This study investigated associations between intakes of protein, arginine, lysine and subsequent 6-year change in body composition among 8-10-year-old children. METHODS: Data of 364 children were collected from Odense, Denmark, during 1997-1998 and 6-year later as part of the European Youth Heart Study. Body mass index among children was subdivided by fat free mass index (FFMI) and fat mass index (FMI), based on skinfold measurements. Dietary intake was estimated via 24h recall. Associations between intakes of protein as well as arginine, lysine and change in FFMI and FMI were analysed by multiple linear regressions, adjusted for social economic status, puberty stage and physical activity level. RESULTS: Among lean girls inverse associations were found between protein as well as arginine and lysine intake and change in fat mass index (beta=-1.12+/-0.56, p=0.03, beta=-1.10+/-0.53, p=0.04, beta=-1.13+/-0.51, p=0.03 respectively). Furthermore among girls with a body mass index in the 5th quintile, protein intake was associated with DeltaFFMI (p=0.04), and more specific when LYS intake was high, ARG intake was associated with DeltaFFMI (p=0.04). CONCLUSION: Among girls high protein intakes may decrease body fat gain and increase fat free mass gain, depending on the available amounts and combinations of arginine and lysine. [ABSTRACT FROM AUTHOR]

BACKGROUND & AIMS: Dietary protein plays a role in body weight regulation, partly due to its effects on satiety. The objective was to compare the effects of casein-, soy-, whey-, whey without glycomacropeptide (GMP)-, alpha-lactalbumin-, gelatin-, or gelatin with tryptophan (TRP)-protein breakfasts at two concentrations on subsequent satiety and energy intake (EI). METHODS: Twenty-four healthy subjects (mean+/-SEM BMI: 24.8+/-0.5 kg/m(2); age: 25+/-2 years) received a breakfast; a custard with casein, soy, whey, whey-GMP, alpha-lactalbumin, gelatin, or gelatin+TRP as protein source with either 10/55/35 (normal) or 25/55/20 (high) En% protein/carbohydrate/fat in a randomized, single-blind design. At the precedingly determined time point for lunch, 180 min, subjects were offered an ad lib lunch. Appetite profile (Visual Analogue Scales, VAS) and EI were determined. RESULTS: Both at the level of 10 and 25 En% from protein, EI at lunch was approximately 20% lower after an alpha-lactalbumin or gelatin (+TRP) breakfast (2.5+/-0.2 MJ) compared with after a casein, soy, or whey-GMP breakfast (3.2+/-0.3 MJ, p<0.05). Appetite ratings at 180 min differed 15-25 mm (approximately 40%, p<0.05) between types of protein. Differences in EI were a function of differences in appetite ratings (R(2)=0.4, p<0.001). CONCLUSIONS: Different proteins (alpha-lactalbumin, gelatin, gelatin+TRP) that are approximately 40% more satiating than other proteins (casein, soy, whey, whey-GMP) induce a related approximately 20% reduction of subsequent energy intake. [ABSTRACT FROM AUTHOR]

BACKGROUND: The role of dietary protein in short term satiety is of interest with respect to body weight regulation. AIM: To compare the effects of a high versus a normal soyprotein breakfast on satiety and subsequent energy intake (EI), including 'satiety' hormones and plasma amino acid responses. METHODS: Twenty-five healthy subjects (mean +/- SEM, BMI: 23.9 +/- 0.3 kg/m(2); age: 22 +/- 1 years) received a subject-specific standardized breakfast: a custard with soy as single protein type with either 10/55/35 (normal-protein) or 25/55/20 (high-protein) En% protein/carbohydrate/fat in a randomized, single-blind design. Appetite profile (Visual Analogue Scale, VAS), plasma glucose, insulin, Glucagon-like Peptide 1, ghrelin, and amino acid concentrations were determined for 4 h, determining the sensitive time point to assess EI. Since at 180 min glucose and insulin concentrations still were significantly different, in a second set of experiments subjects received an ad lib lunch at 180 min after the breakfasts; EI was assessed. RESULTS: Overall the 25 En% soy-custard was rated as being more satiating than the 10 En% soy-custard (P < 0.01) and there was a difference at 20 min after breakfast (64 +/- 5 vs. 52 +/- 5 mmVAS, P < 0.05), related to higher postprandial taurine concentrations (P < 0.05). Insulin response was increased more after the 25 En% than after the 10 En% soy-custard (AUC: 7,520 +/- 929 vs. 4,936 +/- 468 mU/l h, P < 0.001). There was no difference in EI (25 En%: 3,212 +/- 280 kJ vs. 10 En%: 3,098 +/- 286 kJ, ns). CONCLUSION: A high soyprotein breakfast is more satiating than a normal soyprotein breakfast related to elevated taurine and insulin concentrations. [ABSTRACT FROM AUTHOR]

High-protein (HP) foods are more satiating and have a higher thermogenic effect than normal protein foods over the short-term as well as the long-term. We hypothesized that acute effects of higher protein intake on satiety may be related to acute metabolic and hormonal responses. The study was a single-blind, randomized, crossover design. Subjects underwent 2 indirect calorimetry tests for measurement of energy expenditure (EE) and substrate oxidation. After a standard subject-specific breakfast, subjects received 1 of 2 randomly assigned treatments: an appropriate protein (AP) lunch (10% energy (E) protein, 60%E carbohydrate, 30%E fat), or a HP lunch (25%E protein, 45%E carbohydrate, 30%E fat). The increase in postlunch EE tended to be greater after the HP lunch (0.85 +/- 0.32 kJ/min) than after the AP lunch (0.73 +/- 0.22 kJ/min) (P = 0.07). The respiratory quotient did not differ between the HP (0.84 +/- 0.04) and the AP (0.86 +/- 0.04) treatments. Satiety visual analogue scales (VAS) scores were significantly higher 30 and 120 min after the HP lunch than after the AP lunch. The area under the curve of the VAS score for satiety was higher after the HP lunch (263 +/- 61 mm/h) than after the AP lunch (AP 236 +/- 76 mm/h) (P < 0.02). Effects of the meals on satiety and diet-induced thermogenesis did not occur simultaneously with changes in plasma ghrelin, glucagon-like peptide 1, and peptide tyrosine-tyrosine concentrations. A single HP lunch, therefore, does not exert its acute effect on satiety through increased concentrations of satiety-related hormones. Other factors, which may explain the HP effect on satiety, may be metabolites or amino acids. [ABSTRACT FROM AUTHOR]

BACKGROUND: It is unclear whether energy-containing drinks, especially those sweetened with high-fructose corn syrup (HFCS), promote positive energy balance and thereby play a role in the development of obesity. OBJECTIVE: The objective was to examine the satiating effects of HFCS and sucrose in comparison with milk and a diet drink. DESIGN: The effects of 4800-mL drinks containing no energy or 1.5 MJ from sucrose, HFCS, or milk on satiety were assessed, first in 15 men and 15 women with a mean (+/-SD) body mass index (BMI; in kg/m(2)) of 22.1 +/- 1.9 according to visual analogue scales (VAS) and blood variables and second in 20 men and 20 women (BMI: 22.4 +/- 2.1) according to ingestion of a standardized ad libitum meal (granola cereal + yogurt, 10.1 kJ/g). RESULTS: Fifty minutes after consumption of the 1.5-MJ preload drinks containing sucrose, HFCS, or milk, 170%-mm VAS changes in satiety were observed. Glucagon-like peptide 1 (GLP-1) (P < 0.001) and ghrelin (P < 0.05) concentrations changed accordingly. Compensatory energy intake did not differ significantly between the 3 preloads and ranged from 30% to 45%. Energy intake compensations were related to satiety (r = 0.35, P < 0.05). No differences were observed between the effects of the sucrose- and HFCS-containing drinks on changes in VAS and on insulin, glucose, GLP-1, and ghrelin concentrations. Changes in appetite VAS ratings were a function of changes in GLP-1, ghrelin, insulin, and glucose concentrations. CONCLUSION: Energy balance consequences of HFCS-sweetened soft drinks are not different from those of other isoenergetic drinks, eg, a sucrose-drink or milk. [ABSTRACT FROM AUTHOR]

BACKGROUND: Genetic variation in the peroxisome proliferator-activated receptor gamma2 (PPARgamma2), glucocorticoid receptor (GRL), and ciliary neurotrophic factor (CNTF) genes may play a role in the etiology of obesity. OBJECTIVE: We examined biological, psychological, and genetic determinants associated with weight maintenance (WM) after weight loss. DESIGN: Subjects (n = 120) followed a 6-wk diet and then a 1-y period of WM. Body weight (BW), body composition, leptin concentration, attitude toward eating (measured with the Three-Factor Eating Questionnaire), physical activity, and the polymorphisms of the PPARgamma2, GRL, and CNTF genes were measured. RESULTS: BW loss was 7.0 +/- 3.1 kg. After 1 y, 21 subjects showed successful WM (<10% regain); 99 were unsuccessful (> or =10% regain). Compared with unsuccessful subjects, successful subjects had a higher increase in dietary restraint over time (4.8 +/- 5.0 and 1.8 +/- 3.9, respectively; P < 0.01) but significantly less sensation of general hunger (-4.0 +/- 4.9 and -1.2 +/- 2.7, respectively; P < 0.05). Successful subjects had a significantly different frequency distribution for the PPARgamma2 (P = 0.05) and GRL (P < 0.05) genes than did unsuccessful subjects. The more successful genotypes showed a higher baseline body mass index and waist circumference (PPARgamma2), a greater decrease in disinhibition of dietary restraint (GRL), and less sensation of hunger (GRL). The G/G genotype (GRL) was an independent predictor of successful WM. CONCLUSION: The different genotypes of the PPARgamma2 and GRL genes contribute to WM, either directly (GRL) or indirectly (PPARgamma2 and GRL) via baseline body mass index and waist circumference, and to changes in Three-Factor Eating Questionnaire scores. Copyright © 2005 American Society for Clinical Nutrition [ABSTRACT FROM AUTHOR]

BACKGROUND: Underreporting of food intake is common in obese subjects. OBJECTIVE: One aim of this study was to assess to what extent underreporting by obese men is explained by underrecording (failure to record in a food diary everything that is consumed) or undereating. Another aim of the study was to find out whether there was an indication for selective underreporting. DESIGN: Subjects were 30 obese men with a mean (+/-SD) body mass index (in kg/m(2)) of 34 +/- 4. Total food intake was measured over 1 wk. Energy expenditure (EE) was measured with the doubly labeled water method, and water loss was estimated with deuterium-labeled water. Energy balance was checked for by measuring body weight at the start and end of the food-recording week and 1 wk after the recording week. RESULTS: Mean energy intake and EE were 10.4 +/- 2.5 and 16.7 +/- 2. 4 MJ/d, respectively; underreporting was 37 +/- 16%. The mean body mass loss of 1.0 +/- 1.3 kg over the recording week was significantly different (P < 0.05) from the change in body mass over the nonrecording week, and indicated 26% undereating. Water intake (reported + metabolic water) and water loss were significantly different from each other and indicated 12% underrecording. The reported percentage of energy from fat was a function of the level of underreporting: percentage of energy from fat = 46 - 0.2 x percentage of underreporting (r(2) = 0.28, P = 0.003). CONCLUSIONS: Total underreporting by the obese men was explained by underrecording and undereating. The obese men selectively underreported fat intake. Copyright © 2000 American Society for Clinical Nutrition [ABSTRACT FROM AUTHOR]