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Body-weight management requires a multifactorial approach. Recent findings suggest that an elevated protein intake seems to play a key role herein, through (i) increased satiety related to increased diet-induced thermogenesis; (ii) its effect on thermogenesis; (iii) body composition; and (iv) decreased energy-efficiency, all of which are related to protein metabolism. Supported by these mechanisms, relatively larger weight loss and subsequent stronger body-weight maintenance have been observed. Increased insulin sensitivity may appear, but it is unclear whether this is due to weight loss or type of diet. The phenomenon of increased satiety is utilized in reduced energy-intake diets, mainly in the ad libitum condition, whereby sustained satiety is achieved with sustained absolute protein intake in grams, despite lower energy intake. Elevated thermogenesis and glucagon-like peptide-1 (GLP-1) appear to play a role in high-protein induced satiety. Under conditions of weight maintenance, a high-protein diet shows a reduced energy efficiency related to the body composition of the body weight regained, that is, in favor of fat-free mass. Indeed, during body-weight loss, as well as during weight regain, a high-protein diet preserves or increases fat-free mass and reduces fat mass and improves the metabolic profile. In the short-term this may be supported by a positive protein and a negative fat balance, through increased fat oxidation. As protein intake is studied under various states of energy balance, absolute and relative protein intake needs to be discriminated. In absolute grams, a normal protein diet becomes a relatively high-protein diet in negative energy balance and at weight maintenance. Therefore, 'high protein negative energy balance diets' aim to keep the grams of proteins ingested at the same level as consumed at energy balance, despite lower energy intakes.International Journal of Obesity (2006) 30, S16-S23. doi:10.1038/sj.ijo.0803487. AD - [1] 1Department of Human Biology, Nutrim, Maastricht University, MD Maastricht, The Netherlands [2] 2Wageningen Centre of Food Sciences, Wageningen, The Netherlands.

Glucagon-like peptide 1 (GLP-1) is a peptide hormone that is released in response to nutrient ingestion. Postprandial GLP-1 release has been reported to be attenuated in obese subjects, but reports on the effect of weight loss on GLP-1 are conflicting. The aim of the present study was to clarify the effect of a weight-loss period and a consecutive weight-maintenance period on nutrient-stimulated GLP-1 release in obese subjects. Nutrient-stimulated (standard breakfast; 1.9 MJ) GLP-1 release was investigated in thirty-two obese subjects on three occasions: before weight loss (T1) (BMI 30.0 (sd 2.5) kg/m(2)); after a 6-week very-low-energy diet (VLED) (T2) (BMI 27.6 (sd 2.3) kg/m(2)); after a 3-month weight-maintenance period (T3) (BMI 27.9 (sd 2.3) kg/m(2)). At each occasion, following a fasting blood sample the test meal was fed and blood was drawn every 30 min for 2 h relative to ingestion in order to determine plasma GLP-1, insulin, glucose and NEFA concentrations. Subjects lost 7 (sd 3.4) kg during the VLED (P

Since long-term weight maintenance (WM) is a major problem, interventions to improve WM are needed. The aim of the study was to investigate whether the addition of protein to the diet might limit weight regain after a weight loss of 5–10 % in overweight subjects. In a randomised parallel study design, 113 overweight subjects (BMI 29·3 (SD 2·5) kg/m2); age 45·1 (SD 10·4) years) followed a very-low-energy diet for 4 weeks, after which there was a 6-month period of WM. During WM, subjects were randomised into either a protein group or a control group. The protein group received 30 g/d protein in addition to their own usual diet. During the very-low-energy diet, no differences were observed between the groups. During WM, the protein group showed a higher protein intake (18 %v.15 %;Pv.3·0 kg;Pv.0·5 (SD 0·5 ) cm;Pv.0·07 0·01; (SD/)P

OBJECTIVE: Investigation of the effect of a green tea-caffeine mixture on weight maintenance after body weight loss in moderately obese subjects in relation to habitual caffeine intake. RESEARCH METHODS AND PROCEDURES: A randomized placebo-controlled double blind parallel trial in 76 overweight and moderately obese subjects, (BMI, 27.5 +/- 2.7 kg/m2) matched for sex, age, BMI, height, body mass, and habitual caffeine intake was conducted. A very low energy diet intervention during 4 weeks was followed by 3 months of weight maintenance (WM); during the WM period, the subjects received a green tea-caffeine mixture (270 mg epigallocatechin gallate + 150 mg caffeine per day) or placebo. RESULTS: Subjects lost 5.9 +/-1.8 (SD) kg (7.0 +/- 2.1%) of body weight (p < 0.001). At baseline, satiety was positively, and in women, leptin was inversely, related to subjects' habitual caffeine consumption (p < 0.01). High caffeine consumers reduced weight, fat mass, and waist circumference more than low caffeine consumers; resting energy expenditure was reduced less and respiratory quotient was reduced more during weight loss (p < 0.01). In the low caffeine consumers, during WM, green tea still reduced body weight, waist, respiratory quotient and body fat, whereas resting energy expenditure was increased compared with a restoration of these variables with placebo (p < 0.01). In the high caffeine consumers, no effects of the green tea-caffeine mixture were observed during WM. DISCUSSION: High caffeine intake was associated with weight loss through thermogenesis and fat oxidation and with suppressed leptin in women. In habitual low caffeine consumers, the green tea-caffeine mixture improved WM, partly through thermogenesis and fat oxidation.

BACKGROUND: A relatively high percentage of energy intake as protein has been shown to increase satiety and decrease energy efficiency during overfeeding. AIM: To investigate whether addition of protein may improve weight maintenance by preventing or limiting weight regain after weight loss of 5-10% in moderately obese subjects. DESIGN OF THE STUDY: In a randomized parallel design, 148 male and female subjects (age 44.2 +/- 10.1 y; body mass index (BMI) 29.5 +/- 2.5 kg/m2; body fat 37.2 +/- 5.0%) followed a very low-energy diet (2.1 MJ/day) during 4 weeks. For subsequent 3 months weight-maintenance assessment, they were stratified according to age, BMI, body weight, restrained eating, and resting energy expenditure (REE), and randomized over two groups. Both groups visited the University with the same frequency, receiving the same counseling on demand by the dietitian. One group (n=73) received 48.2 g/day additional protein to their diet. Measurements at baseline, after weight loss, and after 3 months weight maintenance were body weight, body composition, metabolic measurements, appetite profile, eating attitude, and relevant blood parameters. RESULTS: Changes in body mass, waist circumference, REE, respiratory quotient (RQ), total energy expenditure (TEE), dietary restraint, fasting blood-glucose, insulin, triacylglycerol, leptin, beta-hydroxybutyrate, glycerol, and free fatty acids were significant during weight loss and did not differ between groups. During weight maintenance, the 'additional-protein group' showed in comparison to the nonadditional-protein group 18 vs 15 en% protein intake, a 50% lower body weight regain only consisting of fat-free mass, a 50% decreased energy efficiency, increased satiety while energy intake did not differ, and a lower increase in triacylglycerol and in leptin; REE, RQ, TEE, and increases in other blood parameters measured did not differ. CONCLUSION: A 20% higher protein intake, that is, 18% of energy vs 15% of energy during weight maintenance after weight loss, resulted in a 50% lower body weight regain, only consisting of fat-free mass, and related to increased satiety and decreased energy efficiency.

The present study was conducted to investigate whether green tea may improve weight maintenance by preventing or limiting weight regain after weight loss of 5 to 10% in overweight and moderately obese subjects. The study had a randomised, parallel, placebo-controlled design. A total of 104 overweight and moderately obese male and female subjects (age 18–60 years; BMI 25–35kg/m2) participated. The study consisted of a very-low-energy diet intervention (VLED; 2·1MJ/d) of 4 weeks followed by a weight-maintenance period of 13 weeks in which the subjects received green tea or placebo. The green tea contained caffeine (104mg/d) and catechins (573mg/d, of which 323mg was epigallocatechin gallate). Subjects lost 6·4 (sd 1·9) kg or 7·5 (sd 2·2) % of their original body weight during the VLED (PP

Effect of conjugated linoleic acid supplementation after weight loss on appetite and food intake in overweight subjects.Kamphuis MM, Lejeune MP, Saris WH, Westerterp-Plantenga MS.Department of Human Biology, Faculty of Health Sciences, Maastricht University, Maastricht, The Netherlands. M.Kamphuis@hb.unimaas.nlOBJECTIVE: To study the effects of 13 weeks conjugated linoleic acid (CLA) supplementation in overweight subjects on body-weight maintenance, parameters of appetite and energy intake (EI) at breakfast after weight loss. DESIGN: This study had a double-blind, placebo-controlled randomized design. SUBJECTS: A total of 26 men and 28 women (age 37.8+/-7.7 y; body mass index 27.8+/-1.5 kg/m(2)). INTERVENTIONS: Subjects were first submitted to a very-low-calorie diet (VLCD; 2.1 MJ/day) for 3 weeks after which they started with the 13-week intervention period. They either received 1.8 g CLA or placebo per day or 3.6 g CLA or placebo per day. Additionally, subjects of the high dosage intervention replaced their habitual lunch by one meal of a protein-rich, low-energy supplement. EI was measured at breakfast and appetite profile after an overnight fast. RESULTS: The mean body weight loss was 6.9+/-1.7% of their original body weight. Multiple regression analysis showed that at the end of the 13-week intervention, CLA did not have an effect on body weight regain. Feelings of fullness and satiety were increased and feelings of hunger were decreased after 13 weeks intervention by CLA compared to placebo, independent of %body weight regain. However, EI measured at breakfast was not affected by CLA. CONCLUSION: Appetite (hunger, satiety and fullness) was favorably, dose-independently affected by a 13-week consumption of 1.8 or 3.6 g CLA/day. This did not result in a lower EI at breakfast or an improved body-weight maintenance after weight loss.

The aim of the present study was to investigate whether capsaicin assists weight maintenance by limiting weight regain after weight loss of 5 to 10%. In this randomized double-blind placebo-controlled study, ninety-one moderately overweight subjects were randomly assigned to an intensive group that underwent all the measurements, and an extensive group that underwent the same measurements except the metabolism measurements. After a 4-week very-low-energy diet (VLED) intervention, a 3-month weight-maintenance period followed. During weight maintenance, subjects were divided into a capsaicin (135 mg capsaicin/d) and a placebo group. Body mass was measured before and after the VLED and after 1, 2 and 3 months of weight maintenance. The mean body-mass loss during the VLED was 6·6 (sd2·0) kg (7·8 (sd1·8)% initial body mass), and was not different between the subsequent treatment and placebo group. During weight maintenance, mean % regain during treatment was not significantly different compared with placebo (33·3 (sd35·7)v.19·2 (sd41·8)%,P=0·09). RQ was significantly less increased during weight maintenance in the treatment group compared with placebo (0·04 (sd0·06)v.0·07 (sd0·05),P< 0·05), indicating a relatively more sustained fat oxidation. Fat oxidation (g/h) after weight maintenance was higher in the capsaicin group compared with placebo (4·2 (sd1·1)v.3·5 (sd0·9),P< 0·05). These results indicate that capsaicin treatment caused sustained fat oxidation during weight maintenance compared with placebo. However, capsaicin treatment has no limiting effect on 3-month weight regain after modest weight loss.

Enterostatin (ENT) has been found to inhibit food intake and selectively inhibit fat intake in rats. Both peripheral and central mechanisms have been proposed. It also has been suggested that ENT may increase thermogenesis. The present study investigated the effects of oral ENT administration on food intake, energy expenditure and body weight in subjects with a preference for a high-fat diet. In a double-blind, placebo-controlled, randomized and crossover design, nine female and three male healthy subjects (age 34 (sd 11) years, BMI 24·5 (sd 2·5) kg/m2) with a preference for a high-fat diet ingested ENT (3 × 15 mg/d) or placebo (PLA) while consuming a high-fat diet ad libitum for 4d. Eight subjects ended each intervention with a 36h stay in the respiration chamber, continuing the diet and treatment. Body-weight loss was significant (ENT 0·8 (se 0·3) kg, Pse 0·3) kg, Pse 2·6), PLA 35·9 (se 3·2) MJ), macronutrient composition, hunger, satiety and hedonic scores during the 4d high-fat diet. Energy expenditure (24h) (ENT 9·6 (se 0·4), PLA 9·5 (se 0·4) MJ), sleeping and resting metabolic rate, diet-induced thermogenesis, activity-induced energy expenditure and 24h RQ (ENT 0·77 (se 0·01), PLA 0·77 (se 0·01)) were similar for both treatments. We conclude that oral ENT administration did not affect food intake, energy expenditure or body weight in subjects with a preference for a high-fat diet experiencing a negative energy and fat balance.

Effects of dietary restraint vs exercise during weight maintenance in obese men.Lejeune MP, Van Aggel-Leijssen DP, Van Baak MA, Westerterp-Plantenga MS.Department of Human Biology, University of Maastricht, Maastricht, The Netherlands. M.Lejeune@HB.UNIMAAS.NLOBJECTIVE: To investigate the effect of dietary restraint with or without exercise during weight maintenance after energy restriction. SUBJECTS AND METHODS: In total, 40 obese male subjects (mean BMI 32.3 kg/m(2); mean age 39 y) were recruited and randomly divided into a diet (D; n=20) and a diet plus exercise (DE; n=20) group. Both groups participated in an energy restriction programme (ER), which was followed by a weight maintenance phase (WM). Subjects in the DE also participated in an exercise programme. Body mass (BM) and the scores on the three factor eating questionnaire (TFEQ) were measured before and after the ER and after WM. RESULTS: No significant differences between both groups were found. All data taken together showed that BM loss during ER was explained by initial BM (r(2)=0.3, P

Effect of dietary restraint during and following pegylated recombinant leptin (PEG-OB) treatment of overweight men.Lejeune MP, Hukshorn CJ, Saris WH, Westerterp-Plantenga MS.Department of Human Biology, Maastricht University, Maastricht, The Netherlands. M.Lejeune@HB.UNIMAAS.NLOBJECTIVE: To examine the effect of dietary restraint during and following pegylated recombinant leptin (PEG-OB protein) treatment in overweight men. DESIGN: A randomized double-blind placebo-controlled trial in 24 overweight men (BMI: 28.8+/-0.3 kg/m(2); age: 34.8+/-0.9 y). PEG-OB protein (80 mg) or placebo was administered subcutaneously weekly for 6 weeks, combined with a 2.1 MJ/day energy restriction program. Dietary restraint was determined by the Three-Factor Eating Questionnaire before and after treatment, and after 8 weeks follow-up. RESULTS: During treatment dietary restraint increased, and general hunger, resting energy expenditure and respiratory quotient decreased similarly in the PEG-OB and the placebo group. With PEG-OB treatment, additional weight loss (P

Previously, we have shown that satiety and metabolites increased after high-fat modified sham feeding (MSF). We assessed possible metabolic effects due to oral stimulation with a high-fat sham-fed 'meal', in comparison with a high-fat fed meal and with water, in the postprandial state. Fourteen healthy women (aged 18-40 years; BMI 22.5 (sd 3) kg/m2) were fed in energy balance during 4 d with a 50 % enegy as carbohydrate, 15 % energy as protein and 35 % energy as fat menu. On day 4, subjects were given one out of three test lunches, 5 h after a high-fat breakfast, in random order: a high-fat MSF lunch, water (W) or the same lunch to be eaten (E), during their 36 h stay in the respiration chamber, where substrate oxidation, 24 h energy expenditure (EE) and appetite profile were measured. Oral fat stimulation by MSF increased EE (W 6.3 (sd 0.8) v. MSF 6.9 (sd 1.0) kJ/min and E 6.8 (sd 0.7) kJ/min; P < 0.04) for 1 h, increased plasma insulin concentrations (t = 15; W 10.0 (sd 3.4) v. MSF 13.2 (sd 4.0) v. E 22.3 (sd 3.3) units/l; P < 0.0001), attenuated changes in plasma NEFA concentrations (t = 15, W 432 (sd 108) v. MSF 418 (sd 146) v. E 282 (sd 72) mumol/l; P < 0.0001), plasma TAG concentrations (t = 60; W 1092 (sd 548) v. MSF 1116 (sd 493) mumol/l and E 1350 (sd 352) mumol/l; P < 0.02) and plasma glycerol concentrations (t = 15, W 87 (sd 29) v. MSF 74 (sd 34) mumol/l and E 67 (sd 18) mumol/l; P < 0.03). Over a longer period of time, MSF had no effects on substrate oxidation, diet-induced thermogenesis or total EE. In addition to the previously observed metabolic effects of oral stimulation with fat, EE is stimulated up to 1 h after the MSF meal.

Background: It is hypothesized that low dietary fat oxidation makes subjects prone to weight gain. Objective: The aim of the study was to determine dietary fat oxidation in normal, overweight, and obese subjects. Design: The subjects were 38 women and 18 men with a mean (SD) age of 30 12 y and a body mass index (in kg/m 2 )o f 25 4 (range: 18–39). Dietary fat oxidation was measured with deuterated palmitic acid, given simultaneously with breakfast, while the subjects were fed under controlled conditions in a respiration chamber. Body composition was measured by hydrodensitometry and deuterium dilution. Results: Dietary fat oxidation, measured over 12 h after breakfast, rangedfrom4%to28%withamean(SD)of166%.Dietaryfat oxidation was negatively related to percentage body fat, and lean subjects had the highest and obese subjects the lowest values (r 0.65, P 0.001). Conclusion: The observed reduction in dietary fat oxidation in subjects with a higher percentage body fat may play a role in human obesity. Am J Clin Nutr 2008;87:132–5.

BACKGROUND: The mechanism of protein-induced satiety remains unclear. OBJECTIVE: The objective was to investigate 24-h satiety and related hormones and energy and substrate metabolism during a high-protein (HP) diet in a respiration chamber. DESIGN: Twelve healthy women aged 18-40 y were fed in energy balance an adequate-protein (AP: 10%, 60%, and 30% of energy from protein, carbohydrate, and fat, respectively) or an HP (30%, 40%, and 30% of energy from protein, carbohydrate, and fat, respectively) diet in a randomized crossover design. Substrate oxidation, 24-h energy expenditure (EE), appetite profile, and ghrelin and glucagon-like peptide 1 (GLP-1) concentrations were measured. RESULTS: Sleeping metabolic rate (6.40 +/- 0.47 compared with 6.12 +/- 0.40 MJ/d; P < 0.05), diet-induced thermogenesis (0.91 +/- 0.25 compared with 0.69 +/- 0.24 MJ/d; P < 0.05), and satiety were significantly higher, and activity-induced EE (1.68 +/- 0.32 compared with 1.86 +/- 0.41; P < 0.05), respiratory quotient (0.84 +/- 0.02 compared with 0.88 +/- 0.03; P < 0.0005), and hunger were significantly lower during the HP diet. There was a tendency for a greater 24-h EE during the HP diet (P = 0.05). Although energy intake was not significantly different between the diet groups, the subjects were in energy balance during the HP diet and in positive energy balance during the AP diet. Satiety was related to 24-h protein intake (r2 = 0.49, P < 0.05) only during the HP diet. Ghrelin concentrations were not significantly different between diets. GLP-1 concentrations after dinner were higher during the HP than during the AP diet (P < 0.05). CONCLUSION: An HP diet, compared with an AP diet, fed at energy balance for 4 d increased 24-h satiety, thermogenesis, sleeping metabolic rate, protein balance, and fat oxidation. Satiety was related to protein intake, and incidentally to ghrelin and GLP-1 concentrations, only during the HP diet.

The effect of conjugated linoleic acid supplementation after weight loss on body weight regain, body composition, and resting metabolic rate in overweight subjects.Kamphuis MM, Lejeune MP, Saris WH, Westerterp-Plantenga MS.Department of Human Biology, Faculty of Health Sciences, Maastricht University, The Netherlands. M.Kamphuis@hb.unimaas.nlOBJECTIVE: To study the effects of 13 weeks conjugated linoleic acid (CLA) supplementation in overweight subjects after weight loss on weight regain, body composition, resting metabolic rate, substrate oxidation, and blood plasma parameters. DESIGN: This study had a double-blind, placebo-controlled randomized design. Subjects were first submitted to a very-low-calorie diet (VLCD 2.1 MJ/d) for 3 weeks after which they started with the 13-week intervention period. They either received 1.8 g CLA or placebo per day (low dosage, LD) or 3.6 g CLA or placebo per day (high dosage, HD). SUBJECTS: A total of 26 men and 28 women (age 37.8+/-7.7 y; body mass index (BMI) 27.8+/-1.5 kg/m(2)). MEASUREMENTS: Before VLCD (t=-3), after VLCD but before CLA or placebo intervention (t=0) and after 13-week CLA or placebo intervention (t=13), body weight, body composition (hydrodensitometry and deuterium dilution), resting metabolic rate, substrate oxidation, physical activity, and blood plasma parameters (glucose, insulin, triacylglycerol, free fatty acids, glycerol and beta-hydroxy butyrate) were measured. RESULTS: The VLCD significantly lowered body weight (6.9+/-1.7%), %body fat, fat mass, fat-free mass, resting metabolic rate, respiratory quotient and plasma glucose, insulin, and triacylglycerol concentrations, while free fatty acids, glycerol and beta-hydroxy butyrate concentrations were increased. Multiple regression analysis showed that at the end of the 13-week intervention, CLA did not affect %body weight regain (CLA LD 47.9+/-88.2%, CLA HD 27.4+/-29.8%, Placebo LD 32.0+/-42.8%, Placebo HD 22.5+/-37.9%). The regain of fat-free mass was increased by CLA (LD 6.2+/-3.9, HD 4.6+/-2.4%) compared to placebo (LD 2.8+/-3.2%, HD 3.4+/-3.6%), independent of %body weight regain and physical activity. As a consequence of an increased regain of fat-free mass by CLA, resting metabolic rate was increased by CLA (LD 12.0+/-11.4%, HD 13.7+/-14.4%) compared to placebo (LD 9.1+/-11.0%, HD 8.6+/-8.5%). Substrate oxidation and blood plasma parameters were not affected by CLA. CONCLUSION: In conclusion, the regain of fat-free mass was favorably, dose-independently affected by a 13-week consumption of 1.8 or 3.6 g CLA/day and consequently increased the resting metabolic rate. However, it did not result in improved body weight maintenance after weight loss.