The recently published CALERIE trial should sound the death knell of every fad diet that ever was, is, or would be (it won’t, of course). The study showed, in the proverbial nutshell, that calorie restriction, per se, causes weight loss in the overweight, which in turn causes an array of improvements in the customary measures of cardiometabolic risk.
You can get more details on the study if you like, but I’m inclined to leave it there. Replace the prevailing, utterly rule-free “see food” diet (i.e., I see food, and I eat it…) with any set of rules — all carbs; no carbs; nothing but cabbage soup; nothing but grapefruit; only this with only that; ketogenic, macrobiotic, Dukan, HCG, or any cockamamie nonsense you like — and in the short term, you will wind up restricting choice and calories, losing weight, and because of weight loss, looking transiently like you’ve improved your health, too, without meaningfully or sustainably doing so.
Then, there’s the calories underlying all this, the subject of intense and frequent fascination, preoccupation, doubt, debate, and — well, perpetual nincompoopery. As promised, I want to make this topic combustibly simple, and then once and for all — strike a match to it.
1) Calories, per se, are like the volume of fuel in a fuel tank. More fuel, other things being equal, means more miles to drive. Gas gauges in cars would not measure the changing volume of fuel if it didn’t matter; gas gauges at gas stations wouldn’t do so either; and you would not pay more, or less, depending on the number of gallons (or, for our friends elsewhere in the world, liters) you determined to pump. But gauges do measure volume, and dollars do flow with it — because quantity so obviously does matter. More fuel, more energy, more driving.
2) The kind of fuel you put in the tank is like your diet.If the calories you consume are like the volume of gasoline in a fuel tank, then the composition of your diet is like the composition of that fuel. Obviously, the importance of gallons does nothing to denounce the importance of: what kind of fuel?
You would never think that if the gallons matter, then it can’t possibly matter whether the gas is regular, plus, or super; clean, contaminated, or diluted with water; or the pulverized dust of Doritos or doughnuts, and yet when it comes to our bodies, we talk ourselves into exactly such patent silliness. Stop.
3) Your body is like the car, only more so.You know that a more fuel-efficient car will travel further on any given amount of any given fuel than a less efficient car. The stupefying mystery of this is not a topic of constant, breathless conjecture; you will not see it parsed into competing theories on morning shows or in best-selling books offering mutually exclusive insights. Of course a more fuel-efficient car is more fuel efficient. That does not refute the relevance of fuel volume (gallons), or fuel type (quality) — it is just also true.
And there’s more. The same car will run more or less well, further or less far, on the same volume of the same fuel based on…other aspects of its overall condition. Under-inflated tires, clogged filters, or degradation of circulating fluids (e.g., oil), will all change the interactions of a car, fuel volume, and fuel quality. So, too, for the human body and food.
And, even as weight change itself can change the interaction of a body and the calories that sustain it, so can changing the load of a car alter its fuel efficiency. Load your car with rocks, and you will see that much more fuel is required to travel the same distance. The human body is rather the same: larger, heavier bodies (i.e., you before weight loss) need more calories to function the same as smaller, lighter bodies (i.e., you after weight loss).
One final analogy: higher quality fuel can reduce the volume of fuel required for a car to go a certain distance. For you, higher quality food choices can reduce the calories required to fill you up to satisfaction, and nourish you fully. Clean, high quality fuel for a vehicle, in other words, is like nutrient-dense, wholesome food for you.
Calories = gallons; diet quality = fuel caliber; your body = the vehicle. Calories do count, and are combustibly simple. If I may borrow some closing brashness from Rihanna: now, shut up and drive.
Dr. David L. Katz , is author of The Truth about Food and president of the True Health Initiative