It may sound like an obvious thing to say, but if you want to lose weight the best way is to diet and take regular exercise, rather than do just one or the other. That's the verdict of researchers from the Fred Hutchinson Cancer Research Center in Seattle.
Well that's hardly the most innovative scientific statement we've heard this week. But the surprising part - at least according to the researchers - is just how much of a difference it makes if you combine diet and exercise, compared to just watching what you eat or being more active.
In their study, published in the journal Obesity, the researchers took a group of 439 overweight-to-obese women and assigned each into one of four groups. One group just exercised more (45 minutes of moderate aerobic exercise per day, five days a week), while another reduced their calories but did no extra exercise. The third group did both - that is, they exercised five days a week and they restricted their calories - and the fourth group did nothing at all.
At the end of the study, the women who just exercised lost, on average, 2.4 of their weight. But those who dieted and exercised lost nearly 11% of their starting weight - which, in the study, worked out at an average of 19.8lb.
"This study shows that you get the biggest bang for your buck by combining a healthy weight-loss diet with regular, moderate-intensity aerobic exercise," says Dr Anne McTiernan, director of the research centre.
So there you have it. If you want to lose weight, you've got to cut calories and burn them. But hang on, didn't we know that already?