The method most commonly used to assess the number of calories in foods is flawed, overestimating the energy provided to the body by proteins, nuts and foods high in fiber by as much as 25 percent, some nutrition experts say.
“The amount of calories a person gets from protein and fiber are overstated,” said Geoffrey Livesey, the head of Independent Nutrition Logic, a nutrition consulting company in Britain, and a nutrition consultant to the United Nations. “This is especially misleading for those on a high-protein, high-fiber diet, or for diabetics” who must limit their intake of carbohydrates.
The New Logic of Calorie-Counting
Can you determine which of these foods provide fewer calories than originally counted?
An adult aiming to take in 2,000 calories a day on a low-carbohydrate, high-protein diet may actually be consuming several hundred calories less, he and other experts said. Calorie estimates for junk foods, particularly processed carbohydrates, are more accurate.
The current calorie-counting system was created in the late 1800s by Wilbur Atwater, a scientist at the Department of Agriculture, and has been modified somewhat over the past 100 years. Researchers place a portion of food in a device called a calorimeter and burn it to see how much energy it contains. The heat is absorbed by water; one calorie is the amount of energy needed to raise the temperature of one gram of water by one degree Celsius.