Thursday, June 16, 2011

All Calories Are Not Created Equal

Common sense observation tells us that all calories are not created equal I mean if two groups of people maintain a daily intake of 2000 calories and group 1 gets all their calories from toast, coffee with cream and sugar, hamburger and fries, pizza, ice cream and sugared soft drinks and group 2 gets all theirs from egg whites, oatmeal, chicken, fish, green vegetables, sweet potatoes, brown rice, and sugar free beverages, it doesn’t take a degree in astrophysics to figure out that group 1 will lose faster, look better, feel better, and perform better than group 2. But more often than not,  weight loss and weight gain is often viewed strictly a matter of "calories in versus calories out”.  Like if you "burn" more calories than you take in, you will lose weight regardless of the calorie source and if you eat more calories than you burn off each day, you will gain weight, regardless of the calorie source. In other words, “a calorie is a calorie” whether it comes from protein, fat or carbohydrates. But in actuality can all calories really be created equal? 

Going by what I said, it is hard to see how is it that any number of registered dieticians, physicians and others in the medical community still hold to the all calories are equal idea. Maybe it could it be that mainstream nutrition hasn’t caught up with modern science but it just doesn’t sit right with me. 

Going to go all science nerd for a second! 
Scientifically a calorie is defined as the amount of energy required to raise 1 gram of water 1 degree Celsius. Bio-chemically speaking, calories from fat, protein or carbohydrates might all be considered equal, but when the physiological and psychological effect of calories from different foods are considered, they most definitely are not.

The ‘a calorie is a calorie is a calorie’ thought also ignores the rising volume of studies that provide data shows that diets with identical calorie intakes but different nutrientional ratios have different effects on body composition, physical performance, cholesterol levels, oxidative stress, and a host of other physiological factors. These studies show how different foods affect the calories in - calories out equation and the number you see on the scale.

"Let's take a pure food example," says Anne-Marie Nocton, MS, MPH, RD. "If someone were to eat all of her daily caloric requirement as fried onion rings, would the body respond the same way as if all of the calories came from raw spinach? No, because caloric absorption is affected by the composition of the food itself and by the amount of energy it takes the body to process that food. In this example, the body doesn't need to expend many calories to digest and store fat (in the onion rings) because the digestion and storage process isn't very complex. But the spinach contains fiber, and the structure of a fibrous food means that some of the calories will be 'lost' because the body cannot break it all down."

Researchers at the City of Hope Medical Center in Duarte, California studied two groups of overweight people, both on medically supervised low-calorie liquid diets. One group added 3 ounces of almonds to their daily diet, while the other group added the same amount of calories from complex carbs like popcorn and Triscuit crackers.  Both groups ate the same number of calories daily, about 1,000. During the 24-week study, the almond-eating group lost more weight even though they ate the same number of calories as the carb group.  Same calories, different results.

Dr. Rick Mattes, PhD, MPH, RD, professor of foods and nutrition at Purdue University, notes that the simple act of eating raises your metabolism, and eating certain foods raises metabolism even more. “The energy the body uses in the digestion process is called the thermic effect of food (TEF),” he explains. "Protein has a higher TEF relative to carbohydrate and fat.” **Side note - the thermic effect of protein is about twice that of carbohydrate or fat**

High-protein food has the highest satiety rating, therefore eating a high-protein diet could theoretically help you feel fuller and stay satisfied longer. While high-protein foods are valuable for their fullness factor, foods such as nuts that are rich in fat and protein have also because popular. Many studies have shown that nuts, though high in calories, have high dietary compensation and may even increase metabolism. Mattes brought up one study that found subjects' resting energy expenditure was 11% higher after eating nuts.

Finally, we like to reference the work of Richard Feinman, PhD, Professor of Biochemistry at the State University of New York Downstate Medical Center. In an article published in Nutrition Journal 2004, 3:9 with his colleague, Eugene Fine, MD, Dr. Feinman also states that not all calories are created equal. "For many years nutritionists have been saying, 'a calorie is a calorie,' " Feinman said. "That is, weight gained or lost only depends on the calories in the diet, regardless of the macronutrient composition, that is, protein, carbohydrate, fat. We knew this was not true, so we set out to show that this was not true. I think the bottom line is once you have the idea that all calories are the same, you're not going to try to find the best diet. And I think it's very important to try to find out what's going to be most effective. We don't know that yet, but unless we work at it, we won't find it."

According to Dr. Feinman, “A calorie is a calorie" violates the second law of thermodynamics. And we don’t want to do that, do we?

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