People haven't been counting calories forever (though some days it may feel as if you have). The idea became popular around the turn of the 20th century, according to Jonny Bowden, PhD, CNS, a board-certified nutritionist and author of Living the Low Carb Life: Choosing the Diet that's Right for You from Atkins to Zone, and The 150 Healthiest Foods on Earth: The Surprising, Unbiased Truth About What You Should Eat and Why. At that time, scientist Wilbur Atwater noticed that if you put food in a machine, called a "bomb calorimeter," and burned it, you could measure the ash and heat to find out how much "energy" was released and therefore how much "energy" was in the food. The idea caught on, and people began counting calories -- that is, calculating exactly how many calories were consumed when eating particular foods, and "burned" when engaging in different activities. "A spate of diet books in the early part of the century popularized the notion that it's all about the calories -- and it's been with us ever since," Bowden tells WebMD.
"As far as weight gain is concerned, a calorie is a calorie," says Lisa R. Young, PhD, RD, author of The Portion Teller Plan: The No Diet Reality Guide to Eating, Cheating, and Losing Weight Permanently. But there are a myriad of reasons to base your food choices on criteria other than calorie content. For example, if the food you eat contains fiber, it will keep you feeling full longer, Young says, which can prevent you from reaching for "extra" calories in
order to fill yourself up.
The benefit of choosing fruits, vegetables, and other lower-fat foods is that you get more bang for your buck, says Betsy Klein, RD, LD, a Miami-based dietitian. Carbohydrates and protein have 4 calories per gram, while fats have more than twice as much -- an entire 9 calories per gram. (Alcohol weighs in at 7 calories per gram.) If you're counting calories to lose weight, but eating higher-fat foods like bacon and full-fat cheese, you could potentially consume over half your day's calorie allotment by the end of breakfast, she says. Choosing carbs and protein for your morning meal, on the other hand, like an egg white omelet stuffed with mushrooms, onions, green
peppers, and a small amount of low-fat cheese, will leave you with calories to spare for meals and snacks beyond breakfast.
Why is calorie counting so popular? As Americans, we love easy sound bites, Bowden says. Counting calories (or fat grams) is far easier than actually understanding the complex effects food has on our bodies (and our waistlines). Calories do count, but they are far from the whole picture.
"Food produces hormonal effects in the body," he says. "Some hormones say 'store that fat'; others say 'release sugar'; others say 'build muscle.' Study after study shows that diets based on the same amount of calories, but different proportions of fat, protein and carbohydrates, result in different amounts of weight loss."