The Reproductive Advantages of Fat in Women

A number of proposals have been advanced to explain the evolutionary significance of sex-specific fat distribution in women, focusing primarily on the premature development of breasts in nulliparous human females and consequent permanent breast enlargement (e.g., Cant 1981; reviewed in Caro 1987). Recently, Low et al. (1987; henceforth referred to as LAN) (see also Low et al. 1988) proposed the hypothesis that the sex-specific distribution of fat on women’s breasts and on hips deceives men as to their bearer’s reproductive status (see also Alexander 1971; Low 1979). Their argument is properly based on the individual as the unit of selection. They work from the assumption that “breasts, hips and buttocks evolved in the context of females competing for the attention and parental commitment of powerful resource-controlling males.” Then, arguing that fat laid down in the pelvic and breast areas is ambiguous because it could be confused with a wide pelvis or with glandular tissue, respectively, they reason that fat storage in such areas, respectively, deceives men of the “ease” with which parturition occurs and the ability to produce and store milk. In contrast, they believe that steatopygia (fat deposits on the buttocks) is an unambiguous and, therefore, honest display of fat reserves because it cannot be confused with other tissue. Through de-