>>103734652
The belly chub we like consists of gynoid fat. It contains high amounts of polyunsaturated fatty acids, which are necessary for healthy fetal development. In addition, some studies have indicated that women with a greater proportion of gynoid fat are healthier, assuming they are still at a normal weight. Android fat, which is predominant in men and obese women, has a different composition, and higher amounts of it cause health problems.
TL;DR, hourglass and pear-shaped women tend to be healthier and are more likely to produce healthy babies. That's why we find them attractive.