The major health complication of overweight and obesity is cardiovascular disease (CVD). Although dietary fat is often seen as major cause of obesity, there is no strong evidence that decreasing the dietary fat content as such, without actively improving energy balance, prevents weight gain. The limited and heterogeneous data from long-term randomized trials suggest that a 10% of energy higher fat intake results in equal or at the very most 3 kg larger body weights as compared with higher carbohydrate intake. The consequence of some possible weight gain for CVD risk should be balanced against effects of diet composition independent of body weight. There is strong and consistent evidence from metabolic and clinical studies that under isoenergetic conditions, diets high in unsaturated fat are more effective for reducing CVD risk than low-fat diets. A quantitative estimation of effects on risk factors indicates that even if increasing unsaturated fat intake at the expense of carbohydrates would produce some weight gain on the long-term, the net effect on CVD risk is probably beneficial.Keywords: dietary fat, carbohydrate, unsaturated fatty acids, cardiovascular disease, risk factors