Association of vegan diet with RMR, body composition and oxidative stress.

BACKGROUND There is increasing evidence to suggest that a vegetarian diet low in fat and high in complex carbohydrates offers the potential for decreasing the risk of chronic disease. However, there is little information about the effect of vegetarian diets on resting metabolic rate (RMR). The objective of this study was to determine the association of vegan diet with RMR and body composition and oxidative stress. MATERIAL AND METHODOLOGY This research is a cross-sectional descriptive analytic study in which two groups of vegetarians and non vegetarians were compared. RMR was determined by indirect calorimetry, the amount of body fat mass (FM), the percentage of free fat mass (FFM), the markers of oxidative stress (MAD), poteins (PCO) and total anti-oxidatant capacity were measured in 20 vegetarians and 20 non-vegetarians. The two groups were matched with regard to body mass index, sex and menstrual cycle. Energy and macronutrient intakes were determined using a 3-day food record and body composition was determined by bioelectric impedance. RESULTS VEG reported a lower relative intake of protein (40.45 ± 19.41 g, 56.96 ± 11.94 g, p = 0.04), whereas no differences were observed in daily energy, carbohydrate or fat intakes and body composition. NVEG exhibited a higher absolute RMR (1354.7 ± 192.6, 1569.10 ± 348.24 Kcal/24 h, p = 0.02). PCO plasma density was seen significantly higher among non-vegetarians (1.09 ± 3.6, 0.81 ± 0.42, p = 0.02). No significant differences were seen in plasma density of TAC between two groups and MAD was higher amoung vegetarians. CONCLUSION These results suggest that the lower RMR observed in VEG is partially mediated by differences in dietary macronutrient composition.