Recently a nutritionist set out to prove a very important point: It doesn’t matter what kind of food you put in your body. If you eat fewer calories you will lose weight, lower your bad cholesterol and increase your good cholesterol. Don’t get too excited. There’s a big “BUT” at the end of this story. We get this from the ABC News Medical Unit.

Mark Haub is a professor of nutrition at Kansas State University. He decided that for one month he’d eat nothing but Twinkies, full fat milk, steak, nutter-butters and a multivitamin, with one catch: he could only eat 1,800 calories a day. After a month, he was feeling great! He had more energy, he’d stopped snoring, his cholesterol was down and he lost 15 pounds. Basically Haub was proving that weight loss is a simple equation: If you burn more calories than you eat, you’ll lose weight, no matter where those calories come from. Don’t reach for the Twinkies just yet. Eating a low-calorie diet of unhealthy foods might help you lose weight, and you might see some short term health benefits, but that’s just it. They’re short term.

Experts, like our friend Dr. David Katz of the Yale Research Prevention Center, say the effects of a bad diet aren’t felt in weeks. It takes months and years for the negative impact to show up. If all you’re eating is Twinkies you aren’t getting any of the anti-oxidants, phyto-nutrients and fiber that your body needs to fight off cancer and other illnesses. Over the next few decades you’ll be less healthy and more likely to die young. Studies have shown, that we each eat about the same volume of food every day. 1,800 calories worth of Twinkies is a lot less food volume than 1,800 calories worth of lean protein and salad. So within a few weeks your cravings will be out of control, and you’ll start eating more. You’ll start packing the pounds right back on. Dr. Katz says a diet shouldn’t be about taking weight off as fast as possible. You have to be healthy too. After all, what good is skinny if you’re dead at 45?