A study involving identical twins featured a combination of exercise and lowered calorie intake to test the effects on body hormone interactions.
The results showed that as testosterone levels rose, bodyfat and insulin levels, particularly in the central abdominal area, dropped.1 Testosterone levels also rose higher in men who had lower resting insulin levels.
The researchers concluded that high plasma-testosterone levels coupled with low fasting insulin levels are associated with the preservation of lean mass and the loss of abdominal and deep-lying bodyfat. That’s significant because deep abdominal fat stores are linked to a higher risk of cardiovascular disease and diabetes in both men and women. IM
1 Pritchard, J., et al. (1999). Plasma adrenal, gonadal and conjugated steroids following long-term exercise-induced negative energy balance in identical twins. Metabolism. 48:1120-1127.