Low calorie diets are always difficult for obese subjects to follow and lead to metabolic and behavioral adaptation. Therefore, we evaluated the effect of caffeine treatment with calorie shifting diet (CSD) on weight loss. Female subjects (n=60; BMI≥25) completed 4-weeks control diet, 6-weeks CSD (3 repeated phases; each 2-weeks) and 4-weeks follow-up diet, with or without caffeine treatment (5 mg/Kg/day). The first 11 days of each phase included calorie restriction with four meals every day and 4 hours intervals. Significant weight and fat loss were observed after 4-weeks of CSD (5.7 ± 1.24 Kg and 4.84 ± 1.53 Kg) or CSD+Caffeine (7.57 ± 2.33 Kg and 5.24 ± 2.07 Kg) which was consistent for one month of the follow-up (CSD: 5.24 ± 1.83 Kg and 4.3 ± 1.62 Kg, CSD+Caffeine: 12.11 ± 2.31 Kg and 9.85 ± 1.6 Kg, p < 0.05 vs CSD group) and correlated to the restricted energy intake (p < 0.05). During three CSD phases, RMR tended to remain unchanged in both groups.While, CSD or CSD + Caffeine treatments, significantly decreased plasma glucose, total-cholesterol, and triacylglycerol (p < 0.05), even during follow-up period (p < 0.05). HDL-cholesterol was not changed by CSD. Feeling of hunger decreased and subject's satisfaction increased after 4-weeks of CSD (p < 0.05) and remained low to the end of study, while satiety was not affected. Coffeine increased the effect of CSD on feeling of hunger and subject's satisfaction after week 7 (p < 0.05 vs. CSD). These findings indicated that combination of caffeine treatment with CSD could be an effective alternative approach to weight and fat loss with small changes in RMR and improved tolerance of subjects to the new diet.
Keywords: Caffeine; Calorie shifting diet; Diet; Obesity; Resting metabolic rate; Weight loss.