kilka punktow wyjscia do znalezienia odpowiedzi na kilka pytan z gory
Body fat loss achieved by stimulation of thermogenesis by a combination of bioactive food ingredients: a placebo-controlled, double-blind 8-week intervention in obese subjects.
Belza A, Frandsen E, Kondrup J.
Department of Human Nutrition, Centre for Advanced Food Studies, The Royal Veterinary and Agricultural University, Frederiksberg C, Denmark.
[email protected]
BACKGROUND: A combination of tyrosine, capsaicin, catechines and
caffeine may stimulate the sympathetic nervous system and promote satiety, lipolysis and thermogenesis. In addition, dietary calcium may increase fecal fat excretion. OBJECTIVE: To investigate the acute and subchronic effect of a supplement containing the above mentioned agents or placebo taken t.i.d on thermogenesis, body fat loss and fecal fat excretion. DESIGN: In total, 80 overweight-obese subjects ((body mass index) 31.2+/-2.5 kg/m(2), mean+/-s.d.) underwent an initial 4-week hypocaloric diet (3.4 MJ/day). Those who lost>4% body weight were instructed to consume a hypocaloric diet (-1.3 MJ/day) and were randomized to receive either placebo (n=23) or bioactive supplement (n=57) in a double-blind, 8-week intervention. The thermogenic effect of the compound was tested at the first and last day of intervention, and blood pressure, heart rate, body weight and composition were assessed. RESULTS: Weight loss during the induction phase was 6.8+/-1.9 kg. At the first exposure the thermogenic effect of the bioactive supplement exceeded that of placebo by 87.3 kJ/4 h (95%CI: 50.9;123.7, P=0.005) and after 8 weeks this effect was sustained (85.5 kJ/4 h (47.6;123.4), P=0.03). Body fat mass decreased more in the supplement group by 0.9 kg (0.5; 1.3) compared with placebo (P<0.05). The bioactive supplement had no effect on fecal fat excretion, blood pressure or heart rate.
CONCLUSION: The bioactive supplement increased 4-h thermogenesis by 90 kJ more than placebo, and the effect was maintained after 8 weeks and accompanied by a slight reduction in fat mass. These bioactive components may support weight maintenance after a hypocaloric diet.
Body weight loss and weight maintenance in relation to habitual caffeine intake and green tea supplementation.
Westerterp-Plantenga MS, Lejeune MP, Kovacs EM.
Department of Human Biology, Maastricht University, PO Box 616, NL-6200 MD Maastricht, The Netherlands.
[email protected].
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.
Efficacy of a green tea extract rich in catechin polyphenols and caffeine in increasing 24-h energy expenditure and fat oxidation in humans.
Dulloo AG, Duret C, Rohrer D, Girardier L, Mensi N, Fathi M, Chantre P, Vandermander J.
Department of Physiology, Faculty of Medicine, University of Geneva.
[email protected]
BACKGROUND: Current interest in the role of functional foods in weight control has focused on plant ingredients capable of interfering with the sympathoadrenal system. OBJECTIVE: We investigated whether a green tea extract, by virtue of its high content of caffeine and catechin polyphenols, could increase 24-h energy expenditure (EE) and fat oxidation in humans. DESIGN: Twenty-four-hour EE, the respiratory quotient (RQ), and the urinary excretion of nitrogen and catecholamines were measured in a respiratory chamber in 10 healthy men. On 3 separate occasions, subjects were randomly assigned among 3 treatments: green tea extract (50 mg caffeine and 90 mg epigallocatechin gallate), caffeine (50 mg), and placebo, which they ingested at breakfast, lunch, and dinner. RESULTS: Relative to placebo, treatment with the green tea extract resulted in a significant increase in 24-h EE (4%; P < 0.01) and a significant decrease in 24-h RQ (from 0.88 to 0.85; P < 0.001) without any change in urinary nitrogen. Twenty-four-hour urinary norepinephrine excretion was higher during treatment with the green tea extract than with the placebo (40%, P < 0.05). Treatment with caffeine in amounts equivalent to those found in the green tea extract had no effect on EE and RQ nor on urinary nitrogen or catecholamines.
CONCLUSIONS: Green tea has thermogenic properties and promotes fat oxidation beyond that explained by its caffeine content per se. The green tea extract may play a role in the control of body composition via sympathetic activation of thermogenesis, fat oxidation, or both.
szczurki
ale zawsze :D
The effects of caffeine and exercise on body weight, fat-pad weight, and fat-cell size.
Wilcox AR.
The present investigation was designed to test the ability of caffeine ingestion to enhance the reduction of body fat with exercise. Mature male rats (average weight of 442 g) were assigned to four grouping combinations of the two treatment variables: caffeine ingestion (caf, no caf) and exercise training (ex, sed). Two groups trained by swimming 90 min, 5 d/wk (caf-ex, no caf-ex) while two groups served as untrained controls (caf-sed, no caf-sed). Forty-five minutes prior to swimming, doses of saline only or of caffeine dissolved in saline (5 mg caffeine/kg body weight) were administered to the no caffeine and caffeine groups, respectively. After 9 wk of training, body weight and epididymal and retroperitoneal fat-pad weights were significantly reduced in the caffeine groups and in the exercise groups (P less than 0.05). Epididymal fat-cell size was significantly reduced by caffeine treatment, and exercise training reduced fat-cell diameters in both epididymal and retroperitoneal fat-pads (P less than 0.05). The additional 22% reduction in body weight, 25% reduction in epididymal fat-cell size, and 5 and 6% reductions in epididymal and retroperitoneal fat-pad weights, respectively, in the caf-ex group beyond the no caf-ex group support the hypothesis that
fat loss with aerobic exercise can be increased when caffeine is ingested prior to the training sessions.
milego poszukiwania :D
kanarek
nka
Fuckmaster
]
Biniu
spoko_loko
civic
