Obesity has become a worldwide public health problem of epidemic proportions, as it may decrease life expectancy by 7 years at the age of 40 years: excess bodyweight is now the sixth most important risk factor contributing to the overall burden of disease worldwide. Overweight and obesity may increase the risk of erectile dysfunction (ED) by 30-90% as compared with normal weight subjects. On the other hand, subjects with ED tend to be heavier and with a greater waist than subjects without ED, and also are more likely to be hypertensive and hypercholesterolemic. The metabolic syndrome, characterized by a clustering of risk factors associated with insulin resistance and abdominal obesity, associates with ED. Moreover, women with the metabolic syndrome have an increased prevalence of sexual dysfunctions as compared with matched control women. Lifestyle changes aimed at reducing body weight and increasing physical activity induce amelioration of both erectile and endothelial functions in obese men. Moreover, preliminary evidence suggests that a Mediterranean-style diet might be effective in ameliorating sexual function in women with the metabolic syndrome. Lifestyle changes, mainly focussing on regular physical activity and a healthy diet, are effective and safe ways to reduce cardiovascular diseases and premature mortality in all population groups; they may also prevent and treat sexual dysfunctions in both sexes.