A Calorie is a Calorie

When the Reuters News Agency reports on topics in nutrition, and those articles then appear on the Yahoo Web site, they usually tell us such interesting things as how certain dietary supplements may help us to live long enough for space travel from one end of the Milky Way to the other. (For those who can't be bothered looking that up, it would take about a hundred thousand years at the speed of light.)

But when they get it right, I should praise them. (My friends who know something about animal behavior tell me that's called positive reinforcement.) Over the weekend an article was posted about a study from the American Journal of Clinical Nutrition, which I read only when I'm really bored on my trips across the Milky Way. And the conclusion was that a calorie is a calorie.



In other words, for purposes of an effective weight-loss diet, what matters is taking in fewer calories than your body needs to supply its energy needs. The source of those calories matters little.

[For my readers who like a little depth, here is the definition. A calorie is the amount of energy it takes to raise the temperature of a gram of water by one degree centigrade. The calorie of which we usually speak is actually a thousand of those (a kilocalorie), so for clarity it is sometimes called a food calorie. A gram of fat has about 9 calories, carbohydrate 4, protein 4. For the purists, yes, those are approximations.]

The researchers who published this study reached the same conclusion as the investigators who published earlier work in big-name medical journals, including the Journal of the American Medical Association and the New England Journal of Medicine. They looked at diets with various compositions, including higher or lower proportions of fat, protein, and carbohydrates. They asked how well subjects were able to adhere to those diets, how much weight they lost, and how lasting the weight-loss benefit proved to be.

The findings were simple. Weight reduction correlated best with calorie restriction, which - by design - occurred on all of the diets, calculated to reduce caloric intake by 750. Running a 750 calorie-per-day deficit would result in a weight loss of about 39 pounds in six months, whereas study subjects lost about 14 pounds, which suggests adherence was less than strict. What all of the recent studies of this type have shown, not surprisingly, is that amount of weight loss correlates best with adherence.


The conclusion one may reasonably draw from that, and the message nutritionists have often conveyed, is that you should pick the diet that most appeals to you. If you crave protein and fat and are willing to give up starches and sweets, Atkins is for you. If portion control fits your way of thinking, Weight Watchers is the way to go. If you like the idea of being a vegetarian, you should pick the approach advocated by Ornish and McDougall, which markedly restricts both fat and protein.

Of course the diet that appeals to you for short-term use (six months to a year) may not wear well, and "falling off the wagon" will inevitably result in failure to maintain your weight loss.

There is also the question of the long-term effects on health of any of these diets. The best evidence favors the Ornish/McDougall approach. Simply put, that includes only as much protein as the body needs, which means about one gram of dietary protein per kilogram of lean body mass per day. (That isn't very much, and it's difficult to do without being vegetarian). Only about ten percent of daily caloric intake should come from fat, and as little as possible of that from saturated fat.


The rest should come from carbohydrates, with the vast majority from complex carbohydrates, as little as possible from simple carbohydrates (meaning sugars).

By the way, such a diet will typically be fairly high in fiber, which is carbohydrate that is not absorbed in the digestive tract. Fiber contributes to feeling full without adding calories, is good for bowel function, and may reduce cholesterol levels.



It should go without saying (but maybe it doesn't) that exercise is good for both weight reduction and long-term health.

A blend of aerobic and weight training is the ideal method. Aerobic exercise burns calories and promotes cardiovascular health. Weight training increases muscle mass, which not only makes you stronger but increases basal metabolic rate, meaning you burn more calories even when you're sitting around.




So a calorie is a calorie. Does that mean you have to count them? This would be so much easier if the human body came with a meter that measured and displayed caloric intake and expenditure. If you could see those numbers side by side, you could aim for a deficit of 500 per day, which isn't difficult with just a little will power, and you'd lose 50 pounds over the course of a year. Now there is an invention that would make you rich!