Introduction and Part I of this series.
Few stories that begin, “Many Americans clueless…” can really be called “news.” Nonetheless, a recent study made headlines earlier this month by confirming what research has shown time and again: most people don’t know how many calories they supposedly burn. The 2010 Food & Health Survey by Cogent Research asked respondents (1,024 adults “nationally representative of the US population based on the Census”) to estimate how many calories someone of their age, height, weight, and activity levels “should consume” per day. Only 12% got within 100 calories +/- their Estimated Energy Requirement (or EER, the formula currently used by the USDA) and 25% wouldn’t even venture a guess. The remaining 63% were just wrong. This seems to pose a problem for the claim that publishing calorie counts on menus will improve public health. Logically, if people don’t know if they burn 10 or 10,000 calories in a day, which is the range of estimates collected in another survey, conducted in 2006 at the University of Vermont (full text with UMich login), knowing how many calories a particular menu item contains probably isn’t going to do them much good. ![]()
The new calorie publishing policy actually includes a provision to help address this problem—in addition to the calorie counts of all menu items, menus will also have to publish the average daily calorie requirement for adults (2,000 Kcal). New York City also attempted to address the problem of calorie ignorance when it instituted its calorie count requirement by launching an ad campaign aimed at drilling the 2000/day calorie requirement into people’s heads.
But that’s not the kind of calorie ignorance I’m concerned about. For one, I don’t think the success of calorie counts in reducing obesity or improving public health depends on people keeping strict caloric budgets. Enough people have internalized the belief they ought to eat fewer calories that the numbers could be useful as a point of comparison regardless of how many people can accurately estimate how many calories they supposedly burn based on their age, height, weight, and activity level. Even if you’re under the mistaken impression that you’re Michael Phelps, if your goal is to consume less energy, choosing between the 250-calorie sandwich and the 350-calorie one is a simple matter of figuring out which number is smaller. IF calorie counts were accurate, and they inspired at least some people to consistently chose lower-calorie items, and at least some of those people didn’t compensate for those choices by eating more later or being less active, and some of them continued to burn the same number of calories despite eating fewer of them, then the counts would actually have the intended effect. The magnitude of the effect might be small, but it would be in the right direction.
Of course, that’s a big “if.” I already addressed the first condition (calorie counts are often wrong), and will be looking at the next two (people don’t order fewer calories but if they think they have they are likely to compensate later) in more detail in later entries. The problem of most people not knowing how many calories they burn is related to the third condition—the mistaken assumption that people will continue to burn the same number of calories even if they reduce the number of calories they eat.
In other words, the problem isn’t that too few people know that the average adult probably burns something in the vicinity of 2000 calories per day. The problem is that metabolism varies. It doesn’t stick to the formula based on height, weight, age, and activity levels. Most people don’t know how many calories they burn because they can’t know, because it’s dependent on lots of factors that formulas don’t and can’t account for. And one of the things that usually causes people to burn fewer calories per day is eating fewer of them. This starts to get at one of the other reasons I don’t think posting calorie counts will have the desired effect: it’s true that eating fewer calories often leads to short-term weight loss, but the vast majority of people either get hungry and can’t sustain the energy deficit or their bodies adjust to burning fewer calories and erases the deficit. Either way, almost all of them regain all of the weight they lost, and often more. Read more





Recent comments
3 days 9 hours ago
3 days 9 hours ago
3 days 10 hours ago
1 week 4 days ago
2 weeks 3 days ago
2 weeks 3 days ago
2 weeks 3 days ago
2 weeks 3 days ago
2 weeks 3 days ago
2 weeks 3 days ago