Counting calories is now the law of the land. This month, a long-delayed regulation came into effect requiring all food chains with 20 or more locations to list calorie information on their menus. Nutritionists fought to include the rule in the Affordable Care Act as a means of fighting obesity. But it turns out the regulation is based on weak science.
Until now, only a handful of cities mandated calorie counts in restaurants. In New York City, which pioneered the policy in 2008, menu labeling has had no effect on how many calories diners consume, according to one large study by New York University. Other studies show minimal effects. Before the Food and Drug Administration's rule was enacted, the U.S. Department of Health and Human Services commissioned a rigorous controlled experiment from the Rand Corp. The results, published this year, found that if people were informed about the calories in menu items, they purchased food with 38 fewer calories, on average. That's the equivalent of about three walnuts.
Why should the Food and Drug Administration impose a regulation to shave 38 calories off a Chipotle order? The justification from the start, as articulated in a blog post by FDA Commissioner Scott Gottlieb, is that saving even a few dozen calories a day would add up over the course of a year. "Based on that sort of reduction," he wrote, "you could end up consuming 10,000 to 20,000 fewer calories making you three to five pounds slimmer."
Although we've long held on to the intuitive idea that slimming down is merely a matter of beating the math — create a caloric deficit of 3,600 calories and lose a pound of fat — the evidence has been stacking up against it for more than a century.
Since the early 1900s, medical research has shown that people do lose weight on calorie-restricted diets — in the short term. But in most cases, they quickly gain it back. Reviewing hundreds of papers on dieting published already by 1959, two researchers concluded in the AMA Archives of Internal Medicine: "Most obese persons will not stay in treatment for obesity. Of those who stay in treatment, most will not lose weight, and of those who do lose weight, most will regain it."
Moreover, the researchers found, people usually put back on more weight than they'd lost. This cruel twist is due to the fact that a person's metabolic rate slows down to accommodate semi-starvation, but it doesn't bounce back, resulting in a stubbornly depressed metabolism. To maintain that weight loss, it appears a person must restrict calories for life — a state of deprivation that, as it turns out, few humans can sustain. The two AMA authors wrote that the most common "ill effects" of constant hunger include nervousness, weakness and irritability, and, to a lesser extent, fatigue and nausea.
Yet we seem committed to the myth that weight loss is merely a matter of calories in vs. calories out. That's why it's front-page news when researchers discovered that most participants in "The Biggest Loser" reality TV show didn't maintain their new, low weight — and that six years out, several weighed more than when they appeared on the show.
Thankfully, new avenues of research offer hope, as scientists discover factors other than calories that affect how our bodies regulate weight.
Insufficient sleep, for instance, may impair fat loss, as one small controlled trial concluded. Not getting enough sleep also increases the hunger hormone, ghrelin, according to another study. Chronic stress also appears to stimulate ghrelin, as well as the stress hormone cortisol, which is thought to weaken the body's ability to metabolize carbohydrates.
The most promising area of obesity research focuses on the effects of eating carbohydrates. Some 70 clinical trials now show that restricting carbohydrates is a highly effective way of fighting obesity. Low-carbohydrate diets are either equally or more effective than low-calorie diets, according to an analysis in JAMA.
One of the reasons low-carb diets work is precisely that they don't require counting calories. People are allowed to eat as much as they like, so long as they keep carbohydrates low. In part because foods with protein are satiating, people on this diet don't get hungry. Their metabolism doesn't slow down, and they aren't required to sustain a state of semi-starvation.
One recent survey of some 1,500 people found that more than a third of them were able to keep off more than 20 pounds and maintain a low-carb diet for two years or more. Another study, conducted at Stanford, found that subjects successfully lost weight without monitoring calories simply by eating high-quality "real" foods and more vegetables while reducing refined carbohydrates.
Counting calories doesn't work — and it distracts us from what does work. Based on the most up-to-date science, this means curbing carbs instead of counting calories, and getting a good night's sleep. It's a shame the government is requiring restaurants to bear the burden of a policy that is sure to fail.
Nina Teicholz is a science journalist and executive director of the Nutrition Coalition, a group dedicated to evidence-based nutrition policy.