If you take fitness in the evolutionary term, there are two factors – survival and ability to reproduce. It is a notion that men prefer slim and curvy and this correct. The answer to this preference comes from ‘evolutionary fitness’ model that predicts why men prefer a slim and physically attractive woman as partners.
The ‘evolutionary model’ has been created by researchers at the University of Aberdeen in Britain, and the model is based on evolutionary theories.
The model first predicts that any man will first pick out a woman with a body mass index in between 24 and 24.8 as the most physically good-looking and strong. The research team tested the prediction on more than 1,300 people, both males and females, from Britain and nine other countries.
The participants in the study were shown 21 image cards that show females with varying levels of body fatness and were then asked to reorder the 21 images from least attractive to most beautiful.
In all populations, the males and females rated the beauty of the females in the same way. The woman with a Body Mass Index (BMI) of 19 who was the slimmest was rated as most beautiful. As the fatness increased above that value, the less beautiful they were rated.
It is quite contrary to the mathematical ‘fitness’ model that states the most attractive woman is one which has a BMI score of 24 to 24.8.When the age factor is added to this model, the BMI readings vary between 17 and 20.
John Speakman associated with Institute of Genetics and Developmental Biology feels that the men find a slim woman more attractive because we equate it with youth. A BMI of 17-20 equates with a woman of 18-20 years with maximum fertility and least chances of disease in later life.