It's common knowledge that if you want to lose weight, you should combine a low-fat diet and exercise.

Now, according to the International Journal of Obesity and Related Metabolic Disorders, the combination of diet and exercise not only helps you lose weight faster, it also helps you lose it in more important places.

The School of Physical and Health Education of Queen's University in Ontario, Canada, compared the effects of three separate weight-loss regimens: exercise, diet, and diet and exercise combined.

All three methods reduced total weight and body fat, but the diet-exercise combination was the most effective at reducing abdominal fat - the stuff that's hardest to hide. The results were true for both men and women.

So if you just want to make a good impression on the bathroom scale, you can get by with a low-calorie diet. But if you want it to show in the mirror, you'd better do some exercising, too.