Possible factors for altered energy balance across the menstrual cycle: a closer look at the severity of PMS, reward driven behaviors and leptin variations.

This paper reviews the literature on the variations in energy intake (EI), energy expenditure (EE) and the factors which may affect the fluctuations in EI across the menstrual cycle. While no significant changes in body weight and body fat percentage have been noted across the cycle, increases in EI and EE have been well documented during the luteal phase in lean women. The occurrence and severity of the premenstrual syndrome (PMS) and food reinforcement are suggested to affect EI. It is not known, however, whether food reinforcement may affect EI across the menstrual cycle. These factors may also affect overweight/obese women differently than normal-weight women at times during which women may be more prone to episodes of overeating during the menstrual cycle. Certain studies have also noted fluctuations in leptin levels across the menstrual cycle, while others have not. It has also been suggested that variations in leptin levels may affect the rewarding value of food in order to maintain proper body weight and adiposity level. We emphasize that future studies should evaluate the variations in energy balance across the cycle in overweight/obese women, as well as the strength of the relationships between food reinforcement and the severity of PMS with energy and macronutrient intakes.