Everyone knows how to lose weight, right? You eat fewer calories than you burn until you reach your goal weight. Old-fashioned calorie counting edged out all other weight loss diets in 2020, according to a recent International Food Information Council survey.
Few people question the diet dogma of “calories in vs. calories out.” It’s the basic strategy that lies beneath even the newest, technology-enabled weight loss programs. But while calorie counting is grounded in fundamental biological truths, it vastly oversimplifies the complex mechanisms that determine human body weight, according to both research and registered dietitians. Take a closer look at whether or not calorie counting really works for weight loss that lasts, and if it’s the right approach for you.
What Is a Calorie?
A calorie is an exact unit of energy, according to the U.S. Department of Agriculture (USDA); specifically, it is the amount of energy needed to raise the temperature of 1 gram (g) of water by 1 degree Celsius. The “calories” in food are actually kilocalories, or 1,000 of these tiny units. Fats are the most calorie-dense foods we eat, with about 9 kilocalories (kcal) per gram. Carbohydrates and protein each have about 4 kcal per gram. On the most basic level, eating fewer calories than you burn will result in weight loss.
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What Is a Calorie Deficit?
“Calorie deficit” is a term you hear a lot any time weight loss is discussed. This is just another way to say you’re burning more calories than you need to maintain your current body weight. “But remember, it’s almost impossible to know exactly how many calories someone needs,” says Simone Wilson, RD, a registered dietitian and owner of Simone Theresa Nutrition in Philadelphia. It depends on variables including gender, age, activity level, and weight. “Whatever equation you use to estimate this, it’s just that — a rough estimate.”
The Centers for Disease Control and Prevention (CDC) recommends a 500-calorie-a-day deficit for weight loss. Over a week, that adds up to 3,500 calories, the amount long believed to equal 1 pound (lb) of fat (though increasingly this math has come into question). The CDC recommends you create a deficit through a mix of getting more activity, like walking, and making food swaps like drinking sparkling …….