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.
Do Candy Calories Count More?
"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.
Numerous recent studies have established that dieters do initially lose more weight when they eat the same number of calories but fewer carbs and more protein. What's more they seem to do it without ill health effects. Even after two years, a 2010 Temple University study reported that those who eat a diet higher in protein had blood fat profiles and other cardiovascular markers that were just as healthy as those who stuck with the traditionally recommended low fat, high fiber diet.
Additionally, Feinman says there is also a small but very real and meaningful effect in how you digest, absorb and metabolize the energy in different types of nutrients -- and it's greater for proteins than it is for carbs.
"For the same number of calories, you add fewer from protein to the body because they get burned during the digestion process," says Feinman.
What irritates Feinman, Bowden and others who agree with their line of thinking, is that the ADA and most mainstream nutritional organizations refuse acknowledge that the composition of your diet and not just the calorie count can impact your waistline, even though there's plenty of evidence to back up these claims. This is where the debate gets more contentious than election year politics
Calorie Conundrum: Findings Stir Debate
"With so many people struggling with obesity in this country it's a mistake to think that it's all their fault and they aren't trying hard," says Feinman. "Why wouldn't you offer them every single tool that could help?"
Gelbardt counters that the issues are more complicated than the results of studies can often represent.
"While I don't disagree that the body may not process all calories the same in theory, in practical terms it means very little to the average person," he says. "There really isn't much you can do with this information that will help you manage your weight. Your best -- and healthiest -- strategy is still to eat variety of foods and cut back on total calories."
But Gelbardt acknowledges this could change in the future. For example, last year Stanford University researcher Christopher Gardner identified dieting "phenotypes" that indicated genetic differences in how people process each of the different nutrients. These preliminary studies showed that weight loss more than doubled when individuals were correctly matched with a diet -- low fat, low carb or evenly balanced -- based on genetic markers. It's too soon to tell what percentage of the population fits into each category, and results are certainly too preliminary to be useful for individual dieters.
So if you're trying to get the needle on the bathroom scale to point in a favorable direction, whom should you believe? Almost every expert acknowledges that most of us do in fact overeat every type of calorie, and past a certain point it's largely a numbers game. Everyone also seems to agree that we should all be getting more exercise and eating more vegetables -- though there's still some squabbling over fruit. According to Feinman, some fruits have a sugary effect on insulin.
And in the end, no one argues with the fact that for a diet to work, you have to be able to live with it in the long term regardless of where the calories come from.