We all know that foods like chocolate, pizza and ice cream are borderline magical, but they do have calories — a big bunch of them.
On the other end of the calorie spectrum are the good-for-us foods that yes, taste good, but aren't chocolate, pizza and ice cream. These foods do have a couple of things going for them, though—they're typically high in nutrients and low in calories. So low, in fact, that one doctor says they're actually "negative calorie foods," meaning our bodies burn more calories digesting them than they contain.
Only Certain Foods are Touted as "Negative Calorie"
According to Dr. Neal Barnard, author of Foods That Cause You to Lose Weight: The Negative Calorie Effect, low-calorie foods like celery, grapefruit, lemons, limes, apples, lettuce, broccoli and cabbage—along with some legumes and grains—are capable of "jump-starting" metabolism because they take longer to process through the digestive system. This digestion process, like every other activity, burns calories, creating a negative-calorie effect when all's said and done. His theory is that by eating these regularly you lose more weight and keep it off for longer.
But There's a Big Catch
The old saying of "if it sounds too good to be true, it is" applies here. There's no research to support Dr. Barnard's theory.
"Negative calorie foods are a myth, although an understandable one," Ann Marion Willis, a Registered Dietitian in Cape Breton, Nova Scotia, tells Apartment Therapy. Generally, the foods promoted as negative calorie are low in calories, high in water content, and a big source of fiber, says Willis. This translates to a lower calorie intake overall, which does lead to weight loss, just in a different way.
"When these types of food replace higher calorie, low fiber, energy dense foods in our diet, our overall energy intake goes down," she says. "This change in eating patterns is what leads to weight changes, not the individual digestion of each food on its own."
Some research shows that individual macronutrients—fat, protein and carbohydrates—take more energy to digest than others, but we typically don't consume these nutrients individually.
"Worrying about whether your celery burns off five calories more than what it consumes doesn't matter if you're eating it with peanut butter, which is more energy dense," says Willis. "It's very easy to eat five extra calories of peanut butter without noticing."
A Simple Equation for a Healthy Diet
Ultimately, weight loss all boils down to calories in, calories out: Eat more than you burn and you gain weight. Eat less than you burn and you'll lose weight. And yes, you can still eat chocolate, pizza and ice cream and lose weight.
"If you look past the marketing tactics of nutrition and diet books, the key messages are often the same: Eat more vegetables, fruit, whole grains and lean proteins, cook more at home, move more and drink more water," says Willis.
No magic foods, special diet pills or "revolutionary" diet plans will change that.
"When you strip away the 'quick-fix' or 'magic bullet' messages, you realize that you've known what to do all along," says Willis.