A scientific article about self-rated attractiveness published in Body Image, found a clear relationship between BMI and body satisfaction. The study of 52,677 heterosexual adults aged 18 to 65 revealed that women tend to feel best about their bodies when their BMI is between 17.5-20 and men tend to feel best when their BMI is around 23-24.
It appears that women prefer being slightly underweight to on the low-side of normal weight, while men prefer being at the higher end of normal weight.
D.A. Frederick, L.A. Peplau, J. Lever (2006) “The swimsuit issue: Correlates of body image in a sample of 52,677 heterosexual adults” Body Image, Volume 3, Issue 4, December 2006, Pages 413-419. Body Image is an international, peer-reviewed journal that publishes high-quality, scientific articles on body image and human physical appearance.