Another day, another headline-grabbing study that claims to end the obesity debate. Today’s newsmaker: Researchers from the Harvard School of Public Health are claiming that meat, soft drinks, potatoes, and – oh right – sedentary lifestyles are responsible for the country’s obesity problem. But this new study contradicts years of nutrition research that has come before.

We couldn’t agree more on the fourth point, as there has been no credible research to suggest that living on the couch is doing anyone’s waistline any favors. (Quite the opposite, in fact.) On the other hand, there have been plenty of peer-reviewed studies published in recent years to suggest that consuming red meat, sugar-sweetened beverages, and potatoes have no ill effect on weight control. And in some cases, those foods can even help.

Low-carb advocates often malign starchy potatoes, but research published last fall found that spuds can be a nutritious part of a weight-loss diet. At the Obesity Society’s Annual Scientific Meeting in October, researchers from the University of California at Davis presented evidence that eating between 5 and 7 potatoes a week helped study participants lose weight. Furthermore, the National Institute of Diabetes and Digestive and Kidney Diseases counts the potatoes-cause-weight-gain axiom as one of its top obesity myths, noting that the real calories add up when potatoes are “covered with high-fat toppings like butter, sour cream, or mayonnaise.”

What about soft drinks? Research appearing in the March issue of the journal Medicine & Science in Sports & Exercise found that drinking sugary beverages before exercise actually improved physical performance among elite athletes. And another recent study in the Journal of the American Medical Association found that 30 minutes of moderate activity five days a week is all it takes to control blood sugar among people with Type 2 diabetes.

As for red meat, a 2005 study published in the American Journal of Clinical Nutrition found that dieters who included beef in their reduced-calorie diets lost more weight than those who cut it out entirely. The reason, study author Dr. Manny Noakes told CNN, is that lean cuts of red meat are packed with protein, which keeps a belly feeling full for longer.

Researchers will certainly continue trying to come up with new solutions for the obesity problem. No surprise there. But ultimately, no search for a food scapegoat can beat the wealth of research behind a common-sense approach to weight control. It’s all about calories-in and calories-out.