For years, nutritionists told us that all calories are equal. A calorie is a measure, like an inch or a mile, and the measures are constant, even though the kind of food might vary.
What we didn't know until recently is that while the energy in food may be equal in calories, the impact on the human body varies. Calories are indeed equal, but some are utilized differently than others. Some calories are easily converted to fat and stored, while others trigger a sense of satiety and fullness. What remains true, however, is that regardless of what kind of food is consumed, losing weight still requires eating fewer calories than are needed to maintain body weight.
Here are the results of four studies that challenge our insight about how nutrition affects human bodies:
Twinkie Diet Yields Surprising Results: Mark Haub, professor of human nutrition at Kansas State University, set out to prove the premise that all calories are created equal. To test his hypothesis, Haub ate a diet consisting primarily of Twinkies, powdered doughnuts and other sugary foods for 10 weeks.
Haub consumed 1,800 calories per day (down from 2,600, the average daily caloric intake for men of his size) and lost 27 pounds in two months. Surprisingly, his bad cholesterol level dropped by 20 percent and his good cholesterol level rose by 20 percent. Despite his success, Haub does not encourage others to follow in his footsteps because he doesn't yet have enough information to determine why he achieved the results he did.
Simple Carbohydrates Raise Blood Sugar and Fuel Fat Storage: New research indicates that simple carbohydrates, such as bread and pasta, cause blood sugar levels to surge and create excess glucose that filters through the blood. This excess sugar is then converted into triglycerides and stored in the body's fat cells.
Weight Loss Is Aided by Whole-Grain Consumption: Research results reported in the American Journal of Clinical Nutrition suggest that eating whole grains improves weight-loss results. Replacing refined grains with whole grains in the diet of 2,800 participants lowered their levels of fat tissue and improved their overall health.
Resistant Starch Foods Enhance Weight Loss: Step aside, Dr. Atkins! The latest weight-loss diet is based on resistant starch foods, such as beans, whole grains (barley, brown rice, bulgur wheat), bananas, corn, potatoes, yams, oatmeal and lentils. These foods reduce appetite by conveying a feeling of fullness, providing sustained energy and lowering cholesterol levels.
If we've learned anything from these and other studies, we've learned that insight into how the body digests and utilizes energy is an evolving field.
Photo credit: ReneS on Flickr.