Increased fat oxidation during Ramadan fasting in healthy women: an adaptative mechanism for body-weight maintenance.

Possible effects of Ramadan fasting on anthropometric and metabolic variables were investigated in healthy Tunisian Moslem women. Total daily energy intake remained unchanged whereas the qualitative components of nutrients were markedly affected. Neither body weight nor body composition were influenced by Ramadan fasting. Results also indicate the concomitant decrease of plasma insulin concentrations with respiratory and energy expenditure during Ramadan. The circadian evolution of nutrient oxidation rates was modified. Fat oxidation was increased and carbohydrate oxidation was decreased during the light span of the nycthemeron. Qualitative and quantitative circadian changes in feeding associated with Ramadan might be counterbalanced by specific metabolic changes in order to preserve normal body weight and composition.