After menopause, many women experience an increase in the accumulation of fatty tissue around the abdominal girdle. This fat induces insulin resistance. This forces the pancreas to produce more insulin with each meal. This insulin overproduction is an important stimulant of subclinical breast cancer cells. In addition, such cancer cells exhibit a more aggressive behavior. Taking bioidentical hormones after menopause normalizes insulin production. During menopause there is a decrease in muscle mass. The decrease in muscle mass may be a cause of reduced calorie consumption. As a result, with the same eating pattern, the excess calories are no longer burned but are accumulated, perhaps preferentially at the level of the abdominal belt. Reduced muscle mass can therefore also lead to increased insulin resistance. It seems that hormones are important for muscle building and therefore muscle mass. Although many women are overweight, the relationship between hormone intake and muscle building and reduction of fat accumulation has never been thoroughly studied. In a multi-year project we want to compare muscle building with or without hormones in women who do standardized strength and endurance exercises.