Received March 30, 2004
Accepted April 12, 2004

Severe dietary restriction, catabolic states and even short-term caloric deprivation impair fertility in mammals. Likewise, obesity is associated with anovulation and lower pregnancy rates. The nutritional imbalance may adversely reflect on humoral and cellular immune function. The inadequacy between nutritional needs and energy balance would explain the irregularity of ovulation found in the most of environmental disturbances of menstrual pattern. The availability of metabolic sources produced by body stocks can affect gonadotrophins secretion by means of acting on central nervous system. The brain receives information about energy metabolism through peripheral signals such as insulin, insulin-like growth factor-1, leptin and insulin receptor substrate-2. It is proposed an attentive valuation about food intake and energy expenditure (physical activity) like first step to investigate possible etiological factors involved in ovulatory disturbs responsible for infertility, since hypothalamo-pituitary-gonadal axis is sensitive a relatively small calorie intake restriction that culminates to a negative energy balance.