The new study says whether you eat fewer calories or burn them off through exercise, the effect on body composition and fat distribution is the same.

The researchers at the Pennington Biomedical Research Center in Baton Rouge, Louisiana, have found that dieting alone works just as well as a combination of diet and exercise when it comes to reducing weight and fat, but is only the case when the calories consumed and burned, equal out.

Senior study author Dr. Eric Ravussin says it is all about calories and as long as the energy deficit is the same, body weight, fat weight, and abdominal fat will all decrease in the same way.

The study suggests that adding exercise to a weight-loss program will not change body composition and abdominal fat distribution, which challenges the theory that specific exercises can reduce fat in certain areas, in the way for example, some exercises are supposed to specifically target abdominal fat.

For the study Ravussin and his colleagues looked at 35 overweight people.

They were divided into three groups; one were on a diet that reduced their caloric intake by 25 percent (550 to 900 fewer calories a day); the second group reduced their caloric intake by 12.5 percent and increased their physical activity to burn 12.5 percent more calories, while the third group were put on a healthy diet designed to maintain their body weight.

After a six month period the people in both the calorie-restricted and the calorie reduction/exercise groups had lost about 10 percent of their bodyweight, 24 percent of their fat mass, and 27 percent of their abdominal fat but their distribution of body fat remained the same.

Ravussin says the findings suggest that individuals are genetically programmed for fat storage in a particular pattern and that this programming cannot easily be changed.

Ravussin says however that while dieting alone can reduce weight, the researchers noted that exercise also improves aerobic fitness, which offered other health benefits and for overall health, an appropriate program of diet and exercise is still the best option.

The research will be a welcome input into the debate over the often confusing plethora of advice on offer such as low fat, low carb and high fiber diets, as it confirms the message that it is the calories that count when it comes to weight control but exercise offers additional health benefits.

The study is published in the Journal of Clinical Endocrinology & Metabolism.