Even if they're not exactly math whizzes, most dieters are experts at counting calories, tallying up every morsel and sip like a top notch accountant. Somewhere along the line they learn that in order to lose weight, they must create a calorie deficit by eating less fat, less carbohydrates, less protein or a little less of everything -- and whichever way they do it is immaterial. This is weight loss 101.
Now, a growing number of rebel researchers and practitioners are challenging this notion. They're taking the "carbs versus protein" diet debate a step further by maintaining that the source of calories is just as important as the number of them.
Conventional nutrition experts acknowledge that the biochemistry of nutrition is complex but one essential fact is constant: A calorie is a calorie no matter where it comes from.
"For the most part the evidence seems to show that just about any diet will give you about the same results for weight loss as long as you eat sensibly and exercise moderation," says Christine Gerbstadt, a spokesperson for the American Dietetics Association (ADA), a group that advocates "balanced eating plans" like the USDA Food Guide at MyPyramid.gov and the Dietary Approaches to Stop Hypertension (DASH Diet). Both diets are low in fat, sugar, cholesterol and salt, high in complex carbohydrates like whole grains and offer moderate amounts of lean proteins.
But experts like Jonny Bowden, a certified nutritionist and author of Living Low Carb, (Sterling, 2010) insist that all calories are most certainly not created equal. As proof, he points to studies like this 2009 Swedish investigation where volunteers snacked on candy or peanuts to the tune of about 20 extra calories per each half pound of body weight. For example, someone weighing 150 pounds would overindulge by eating a gut busting 1,300 calories a day.
After two weeks, you might expect that both groups were popping the buttons on their pants but this was the case with just the sweet eaters. The peanut snackers did gain a small amount of weight but only about a third of what the candy eaters gained and only the candy group showed an increase in waist circumference, cholesterol and overall blood fats.
"The reason for this is that the simple carbohydrate calories found in candy kept goosing the levels of the hormone insulin," Bowden explains. "Insulin signals sharp increases in blood sugar and enhances the storage of body fat, so when it's constantly elevated you're primed for weight gain."
Bowden says that, because peanuts contain virtually no carbohydrates, they don't trigger the same effect on insulin and the body doesn't rush to pack on the pounds. Even more interesting is that peanut eating group alone experienced a significant rise in their resting metabolism. This could indicate that the fats and proteins from the nuts rev up the body's ability to burn calories which might also help suppress weight gain.
Researcher Richard Feinman, a professor of biochemistry at the SUNY Downstate Medical Center in Brooklyn, notes that insulin sensitivity impacts how you experience hunger as well. "It's a well established fact that eating protein increases satiety and if you feel fuller on fewer calories then you are going to eat less," he points out.