Forget Calories

Highly refined carbohydrates—chips, crackers, white bread, soda, rice—spike our blood sugar. That spike makes the pancreas produce tons of insulin. That insulin tells our body to store energy as fat. Subsequently, as Ludwig and Friedman write in the current Journal of the American Medical Association, “energy expenditure declines and hunger increases, reflecting homeostatic responses to lowered circulating concentrations of glucose and other metabolic fuels. Thus, overeating may be secondary to diet-induced metabolic dysfunction.” That is, refined carbs make us eat more, which makes us fat, which makes us eat more, and so on.

NNAMDI: James, the last time you joined us we talked about the addictive power of foods, whether Oreos are really kind of maybe like crack cocaine. It seems that part of this conversation is about a habit many of us develop in thinking that all calories are just calories, regardless of their sources. There are a lot of people out there now saying, no, all calories are not created equal. What are they saying and why is this significant?

HAMBLIN: It goes right in line with what Dr. Ludwig is saying, that certain calories will cause fluctuations in the body's hormones and blood sugar levels, that will only augment future hunger. So you might be able to temporarily eat a low calorie diet of high-sugar foods but it's going to be unsustainable, you're not going to feel good. You're probably going to feel constantly hungry. And after a few weeks, probably go back to eating more. Whereas if you focus on eating a more balanced whole food diet, you will sustain that longer. And ultimately, you know, we're not proposing that this is overturning the first law of thermodynamics. You will need to burn more calories than you consume [in order to lose weight]. But it's about where you focus that intention of eating. If you think about the calories, I think you tend to make choices to say, well, I can only eat 200 calories now, I'd really like to get that as the most delicious 200 calories possible. I'm going to eat 200 calories of ice cream or soda. ...

LUDWIG: This is, of course, an argument the food industry loves because, by it, there are no bad foods. 

So the old paradigm of weight gain/loss, according to Ludwig and Friedman, looked like this:


And the new one looks like this:



Exercise, too, is about more than burning calories. Ludwig has a good way to think about it:

NNAMDI: Allow me to go to Mark in McLean, Virginia. Mark, you're on the air.

MARK: Hey, Kojo. I wanted to speak about eating clean and sort of healthy eating, in the way that a bodybuilder might eat. I'm currently on a diet and exercise campaign to drop a few pounds. And, you know, I'm eating healthy. I'm eating greens, dark greens. I'm eating fruits, I'm eating whole grains, and I’m eating protein—chicken and fish. And I’m exercising. I've never been a big juice drinker or a soda drinker. I don't do ice cream. Those are the anti-clean-eating foods. So I wanted to ask your panel to comment about eating healthy in combination with exercise as an effective approach to weight loss.

LUDWIG: I think some physical activity is great. I am a strong advocate of it. I think physical activity is, oftentimes profoundly misunderstood in its role in weight management. To burn off the calories in one super-sized fast-food meal, it takes [running] a full marathon. You know, we're much more efficient in holding onto calories than we are we can consume a tremendous amount quickly. And the body, through evolution, doesn't want to be wasteful with its calories. So when you're at extremely high levels of physical activity, you can begin to have a very substantial impact on calorie balance. But for most people, physical activity has a whole nether role. It's not so much burning off calories as is it is in tuning up our metabolism, lowering insulin levels, promoting insulin sensitivity and helping bring those fat cells back into line in behaving more cooperatively with the rest of the body. So, physical activity is good if it's linked to a diet that lowers insulin levels and helps control hunger. But by itself, [it's] not a very good way to lose weight.


So yes, the first law of thermodynamics remains immutable. Energy balance is a true concept. A person will not lose weight if they eat more calories than they burn, and vice versa. But it’s just not a helpful way to think about food, given the fact that foods all around us are labeled with a calorie number that doesn’t fully tell us how that food will affect our metabolism and future hunger.

The proposed new FDA nutrition labels make the calorie number larger. That seems like a mistake. Focusing on calories puts the emphasis in the wrong place. The biochemistry is complex, but the way to think about it is not. Don’t focus on calories; focus on food choices. Eat real food, no added sugar, and you can really forget the numbers.

In 1924 the Journal of the American Medical Association published a prescient idea similar to what Ludwig (and others) advocate. It read:

"Are you ashamed of your weight?" This question is the backbone of an attitude that is rapidly attaining prominence in many parts of the country. Obesity is being made the subject of attack from many quarters. From one direction, the threat of diabetes is heard; from the insurance office, the implication that he is liable to be a "bad risk" greets the corpulent person, while his own discomfort on vigorous effort serves as an even more immediate reminder of the consequences of lessened activity. The dressmaker and the tailor dispense additional reminders in the form of friendly, though unwelcome, gibes that drive the victim of adiposity to seek relief by some means. The outcome has been an unprecedented demand for "reduction" treatments, with a preference for ways that are quick and easy. The quack has not been slow to take advantage of his opportunity to extract a rich reward from the gullible.

When we read that "the fat woman has the remedy in her own hands—or rather between her own teeth," and that "she need not carry that extra weight about with her unless she so wills," there is an implication that obesity is usually merely the result of unsatisfactory dietary bookkeeping. When food intake exceeds energy output, a deposit of fat results. Logic suggests that the latter may be decreased by altering the balance through diminished intake, or increased output, or both … The problem is not really so simple and uncomplicated as pictured.

But that’s the simple paradigm that, 90 years later, Coke and everyone else peddling empty nothing “foods” as simply part of the calorie count are perpetuating.

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James Hamblin, MD, is a senior editor at The AtlanticHe is the host of If Our Bodies Could Talk.


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