Eva M. R. Kovacs

Effects of green tea on weight maintenance after body-weight loss.

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 25-35 kg/m(2)) participated. The study consisted of a very-low-energy diet intervention (VLED; 2.1 MJ/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 (104 mg/d) and catechins (573 mg/d, of which 323 mg 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 (P<0.001). Body-weight regain was not significantly different between the green tea and the placebo group (30.5 (sd 61.8) % and 19.7 (sd 56.9) %, respectively). In the green tea treatment, habitual high caffeine consumption was associated with a higher weight regain compared with habitual low caffeine consumption (39 (sd 17) and 16 (sd 11) %, respectively; P<0.05). We conclude that weight maintenance after 7.5 % body-weight loss was not affected by green tea treatment and that habitual caffeine consumption affected weight maintenance in the green tea treatment.

Additional protein intake limits weight regain after weight loss in humans

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 %; P<0.05), a lower weight regain (0.8 v. 3.0 kg; P<0.05), a decreased waist circumference (-1.2 (SD 0.7) v. 0.5 (SD 0.5 ) cm; P<0.05) and a smaller increase in respiratory quotient (0.03 (SD 0.01) v. 0.07 0.01; (SD/)P <0.05) compared with the control group. Weight regain in the protein group consisted of only fat-free mass, whereas the control group gained fat mass as well. Satiety in the fasted state before breakfast increased significantly more in the protein group than in the control group. After 6 months follow-up, body weight showed a significant group x time interaction. A protein intake of 18 % compared with 15 % resulted in improved WM in overweight subjects after a weight loss of 7.5 %. This improved WM implied several factors, i.e. improved body composition, fat distribution, substrate oxidation and satiety.

Effect of capsaicin on substrate oxidation and weight maintenance after modest body-weight loss in human subjects

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 (SD 2.0) kg (7.8 (SD 1.8) % 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 (SD 35.7) v. 19.2 (SD 41.8) %, P=0.09). RQ was significantly less increased during weight maintenance in the treatment group compared with placebo (0.04 (SD 0.06) v. 0.07 (SD 0.05), 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 (SD 1.1) v. 3.5 (SD 0.9), 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.

The effect of addition of modified guar gum to a low-energy semisolid meal on appetite and body weight loss.

OBJECTIVE: To investigate the effect of addition of modified guar gum (GG) to a low-energy semisolid meal on appetite and body weight (BW) loss.SUBJECTS: Twenty eight mainly overweight male volunteers (age, 19–56 y; body mass index, 29±2 kg m−2; BW, 89.4±9.2 kg).DESIGN: Baseline of one week with self-selected diet. Three treatments of 2 weeks with a low-energy diet divided over three times a day, consisting of a semisolid meal with (SSM+) or without GG (SSM) or a solid meal (SM) with the same energy content (947 kJ) and macronutrient composition, and a dinner of the subjects own choice. Washout periods lasted 4 weeks.RESULTS: Compared to baseline values, reduction in energy intake and BW loss were similar for SSM+, SSM and SM. Appetite (hunger, desire to eat or estimation of how much one could eat) was increased in SSM and in SM compared to baseline, but not in SSM+. Satiety and fullness in SSM+, SSM and SM were similar to baseline. Any intervention was more effective on BW loss when it took place the first time compared to the second and third times (2.6±0.2 kg, 1.7±0.2 kg and 1.1±0.2 kg, respectively; P<0.001). The SM–SSM+–SSM sequence was more effective on BW loss compared to the SSM+–SSM–SM sequence (5.6±1.0 and 2.5±0.6 kg, respectively; P<0.05).CONCLUSION: All the three treatments were equally effective with respect to BW loss. GG addition to a semisolid meal prevented an increase in appetite, hunger and desire to eat, which increase was present in the other treatments. However, differences between treatments were not statistically significant. The order effect shows that repeated 2-week bouts of dieting become increasingly ineffective. The sequence SM–SSM+–SSM was more effective than the sequence SSM+–SSM–SM, probably because compliance was relatively higher with the SSM+ or SSM diet, and compliance decreased towards the end of the complete experiment.

The effect of different dosages of guar gum on gastric emptying and small intestinal transit of a consumed semisolid meal.

Background: There is no consensus about the effect of guar gum supplementation on gastrointestinal transit. It has been suggested that guar gum slows gastric emptying and intestinal transit, thus inducing an increased feeling of satiety. Objective: To investigate whether addition of guar gum to a semisolid meal affects gastrointestinal transit. Design: Eight male subjects were randomly studied four times. They consumed a standard semisolid test meal containing either 0 g, 2.5 g, 3.5 g, or 4.5 g of guar gum. The test meals contained 1 mCi 99mTc-hepatate for scintigraphy and 5 g lactulose for the H2-breath test. Scintigraphic scanning was performed for at least two hours, and gastric half-emptying time (T1/2) was calculated. Breath samples were collected at 15 minute intervals and analyzed for H2-enrichment. The orocecal transit time (OCTT) was then determined. A parameter of intestinal transit (PIT) was obtained by subtracting the T1/2 from the OCTT. Results: There were no significant differences (in minutes) between the different tests in both T1/2 (0 g, t=88.2 ±11, 2.5 g, t=83.3 ±11.9, 3.5 g, t=83.3 ±13.6, 4.5 g, t=72.4 ±7.2, p=0.86) and PIT (0 g, t=149.9 ±26.6, 2.5 g, t=145.5 ±25.6, t=3.5 g, t=175.3 ±17.6, t=4.5 g, t=152.6 ±22.4, p=0.52). Conclusion: Addition of guar gum to a semisolid meal up to a dosage of 4.5 g does not affect gastrointestinal transit. Other mechanisms than gastrointestinal motility are involved in a possible satiating effect of guar gum supplementation.

Effects of 2-week ingestion of (−)-hydroxycitrate and (−)-hydroxycitrate combined with medium-chain triglycerides on satiety and food intake

The aim of this study was to assess the effects of 2 weeks of supplementation with (-)-hydroxycitrate (HCA) and HCA combined with medium-chain triglycerides (MCT) on satiety and energy intake. The experimental design consisted of three intervention periods of 2 weeks separated by washout periods of 2 or 6 weeks in a double-blind, placebo-controlled, randomized, and crossover design. Seven male and 14 female normal to moderately obese subjects (mean+/-S.D.; age, 43+/-10 years; body mass index, 27.6+/-2.0 kg/m(2)) participated in this study. Subjects consumed three self-selected meals and four isoenergetic snacks daily with either no supplementation (PLA), with 500 mg HCA (HCA), or 500 mg HCA and 3 g MCT (HCA+MCT). Each intervention period ended with a test day, consisting of a standardized breakfast and ad libitum a lunch and a dinner. There was a significant body weight (BW) loss during the 2 weeks of intervention (PLA, -0.5+/-0.3 kg, P<.05; HCA, -0.4+/-0.2 kg, P<.05; HCA+MCT, -0.7+/-0.2 kg, P<.01), but this reduction was not different between treatments. Twenty-four-hour energy intake (PLA, 8.1+/-0.3 MJ; HCA, 8.3+/-0.3 MJ; HCA+MCT, 8.4+/-0.3 MJ) and the area under the curve of the appetite-related parameters during the test day were similar for all treatments. Two weeks of supplementation with HCA and HCA combined with MCT did not result in increased satiety or decreased energy intake compared to placebo in subjects losing BW.

The effects of 2-week ingestion of (--)-hydroxycitrate and (--)-hydroxycitrate combined with medium-chain triglycerides on satiety, fat oxidation, energy expenditure and body weight.

OBJECTIVE: Assessment of the effect of 2-week supplementation with (−)-hydroxycitrate (HCA) and HCA combined with medium-chain triglycerides (MCT) on satiety, fat oxidation, energy expenditure (EE) and body weight (BW) loss.DESIGN: Three intervention periods of 2 weeks separated by washout periods of 4 weeks. Double-blind, placebo-controlled, randomised and cross-over design.SUBJECTS: Eleven overweight male subjects (mean±s.d.; age, 47±16 y; body mass index, 27.4 ± 8.2 kg/m2).INTERVENTION: Subjects consumed three self-selected meals and four iso-energetic (420 kJ) snacks daily with either no supplementation (PLA), 500 mg HCA (HCA) or 500 mg HCA and 3 g MCT (HCA+MCT). Each intervention ended with a 36 h stay in the respiration chamber.RESULTS: There was a significant BW loss during the 2 weeks of intervention (PLA, −1.0 ± 0.4 kg, P<0.05; HCA, −1.5 ± 0.5 kg, P<0.01; HCA+MCT, −1.3 ± 0.2 kg, P<0.001), but this reduction was not different between treatments. 24 h EE (PLA, 11.8 ± 0.2 MJ; HCA, 11.7 ± 0.1 MJ; HCA+MCT, 11.5 ± 0.1 MJ), 24 h RQ (0.85 ± 0.00 in all treatments) and the area under the curve of the appetite-related parameters were not different between treatments.CONCLUSION: Two-week supplementation with HCA and HCA combined with MCT did not result in increased satiety, fat oxidation, 24 h EE or BW loss compared to PLA, in subjects losing BW.

The effect of guar gum addition to a semisolid meal on appetite related to blood glucose, in dieting men.

Objective: To investigate whether addition of modified guar gum (GG) to a low-energy semisolid meal might be effective on appetite by modifying the response of blood glucose and other blood parameters.Design: Three intervention periods of 2 weeks each, separated by washout periods of 4 weeks. Randomized and cross-over design.Subjects: Fifteen overweight male subjects (mean±s.d.; age, 44±9 y; body mass index, 28.6±1.8 kg/m2).Intervention: Subjects consumed a low-energy diet divided over three times a day, consisting of a semisolid meal with (SSM+) or without (SSM) addition of 2.5 g GG, or a solid meal (SM) with the same energy content (947 kJ) and macronutrient composition, plus a dinner of the subjects own choice. At the end of each intervention, time and number of meal initiations, dynamics of blood glucose and other blood parameters, and appetite ratings such as hunger and satiety were determined in a time-blinded situation.Results: The changes in blood glucose from meal initiation to blood glucose peak and from peak to nadir were smaller with SSM+ and SM compared to SSM. Satiety before the third meal was higher with SSM+ and SM compared to SSM (P<0.01). Meal pattern, general appetite and total energy intake were similar for all treatments.Conclusions: We conclude that, similar to SM, SSM+ resulted in a more moderate change in blood glucose compared to SSM and positively affected satiety before the third meal, while general appetite, total energy intake and meal pattern did not differ.

Effects of (-)-hydroxycitrate on net fat synthesis as de novo lipogenesis.

(-)-Hydroxycitrate (HCA) might promote weight maintenance by limiting the capacity for de novo lipogenesis (DNL). It was investigated whether HCA may reduce DNL in humans during a persistent excess of energy intake as carbohydrate. In a double-blind, placebo-controlled, randomized and cross-over design, 10 sedentary lean male subjects (mean+/-S.D., age: 24+/-5 years, BMI: 21.8+/-2.1 kg/m2) performed a glycogen depletion exercise test followed by a 3-day high-fat diet (F/CHO/P, 60/25/15% energy; 100% of energy expenditure (EE)) and a 7-day high-CHO diet (F/CHO/P, <5/>85/10% energy; 130-175% of EE; overfeeding). During overfeeding, they ingested 3 x 500 mg/day HCA or placebo (PLA). Each intervention ended with a 60-h stay in the respiration chamber (days 9 and 10). Body weight increased during overfeeding (mean+/-S.E., HCA: 2.9+/-0.2 kg, PLA: 2.8+/-0.2 kg). Respiratory quotient (RQ) was >1.00 in all subjects indicating that DNL was present. On day 9, 24-h EE was lower with HCA compared to PLA (P < 0.05). On day 10, resting metabolic rate and RQ during night were lower (P < 0.01 and P < 0.05, respectively). Non-protein RQ, fat balance and net fat synthesis as DNL tended to be lower (P < 0.1) with HCA compared to PLA indicating lower DNL; activity-induced EE was higher with HCA (P < 0.05) indicating the urge to eliminate the excess of energy ingested. We conclude that an experimental condition resulting in DNL in humans was created and that treatment with HCA during overfeeding with carbohydrates may reduce DNL.

The effects of enterostatin intake on food intake and energy expenditure

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/m(2)) with a preference for a high-fat diet ingested ENT (3 x 15 mg/d) or placebo (PLA) while consuming a high-fat diet ad libitum for 4 d. Eight subjects ended each intervention with a 36 h stay in the respiration chamber, continuing the diet and treatment. Body-weight loss was significant (ENT 0.8 (se 0.3) kg, P<0.05; PLA 1.3 (se 0.3) kg, P<0.001), but not different between treatments. There was no difference between treatments in total energy intake (ENT 37.1 (se 2.6), PLA 35.9 (se 3.2) MJ), macronutrient composition, hunger, satiety and hedonic scores during the 4 d high-fat diet. Energy expenditure (24 h) (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 24 h 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.