Like many people, I’ve tried to lose weight at points in my life. I even succeeded a couple times at losing a substantial amount of weight. Perhaps less like other people, this interest sent me into a decade-long study of human metabolism and nutrition, reading medical journals, scientific papers, popular health books, blogs – the whole mix. I have since abandoned discussing this topic in public much though because the whole conversation around nutrition and weight loss (in America at any rate) is just so ideological and stupid it hurts my brain.
That’s why I practically had an aneurism this morning reading this Vox article. It contains a bit of useful scientific data (such as the Hadza study), but the whole article is just steeped in the mindset of calories being important, and is unable to break out of it even when the data is staring them right in the face.
Let’s put it this way. Nutrition, despite how many people practice it, is subject to scientific inquiry using standard scientific methods. You propose hypotheses and do experiments, and if the results from the experiment contradict your hypothesis, the hypothesis is wrong.
The idea that calories are a central or important to weight gain or weight loss is a hypothesis. And it doesn’t matter how many experiments you do that produce results consistent with the hypothesis. If you do just one experiment that produces results contrary to the hypothesis (all caveats about experimental design and measurement error being a given), then the hypothesis is wrong.
Do you know someone who can eat pretty much whatever and never gains weight? I bet you do, because they’re fairly common. Calories aren’t the story.
Did you notice in that Vox article that the Hazda have the same calorie expenditure as humans in modern societies, and yet they’re all fairly lean? They eat the same number of calories, and burn the same number of calories, but their bodies don’t create large fat deposits. Calories aren’t the story.
Have you ever read an over-feeding study? Probably not, but they’re fascinating. One experiment fed US prisoners (who volunteered for the study in exchange for a reduced sentence) as much food as possible while forcing them to remain as sedentary as possible. We are talking quantities of food between 5,000 and 10,000 calories per day, for months. Most of them gained 5 to 10 lbs and then stopped gaining weight. Their bodies adapted to the new calorie load and the experimenters couldn’t make most of the prisoners gain any weight beyond that point. Calories aren’t the story.
Have you read any medical journal articles about patients on low-calorie diets that don’t lose fat mass? I have. They lose “weight”, sure, but it’s all muscle, bone, and internal organs. They don’t lose fat, even when on a “diet”. Some of them even die of organ failure from starvation even while retaining abundant fat stores. These people aren’t normal by any means, but they are evidence that calories aren’t the story.
Did you read the Men’s Fitness article years ago about the fat triathlete? This guy wasn’t a little fat. He was Santa Claus fat, no matter how many triathlons he did or how many calories his little pedometer said he burned. Exercise isn’t the story either.
Just the examples above, and many, many others, are experimental data. And they disprove the hypothesis that calories consumed (or calories burned by exercise) are the relevant variables in weight loss and gain. (No, again, it still doesn’t matter how many experiments are consistent with those hypotheses. That’s not how science works) If you want to understand how weight loss and gain work, you need to just stop talking about calories entirely for a while. If you can’t break the habit, I suggest biting yourself on the hand very hard every time you use the word “calorie”. It should only take a couple negative-reinforcement lessons to kick the habit.
So what matters? In a word, hormones. Your body’s cells, after all, do not know how many calories you eat in a given day. Each cell in your body is a local decision-maker, deciding whether to do things like burn fatty acid stores or create them. And they make this decision based on how hormonal signals interact with their internal chemistry. (Very similarly, to you Econ nerds, how local economic agents respond to price signals even if they don’t know what’s causing the prices to go up or down)
I’m not going to write the entire book that might be needed to convince you of this. I don’t have the time or inclination for that. I’ll lazily point you to how teenagers go through wild swings of body weight and composition. I’ll suggest you ponder why taking Testosterone and HGH injections causes people to become very lean (in addition to heavily muscled). I’ll suggest that you read studies on how X amount of exercise can cause fat loss, but 3X causes bodyfat composition to increase (Hint: because cortisol makes you retain bodyfat, regardless of calories “burned”). I’ll remind you that any study that measures “weight loss” without considering body composition is useless. I’ll suggest that studies on how artificial lighting can affect sleep, and that in turn affects weight gain, might be worth pondering deeply (unless you think LED lamps somehow throw off excess calories in addition to lumens).
And so forth. Calories aren’t the story (except to the extent they change your hormone profile). Exercise isn’t the story (except to the extent it changes your hormone profile). Hormones are the story.
And that’s all I have to say on this topic for the year 2016, I hope. Maybe one day the Great Establishments of Health & Medicine will come around to finally seeing what’s right in front of their nose. Maybe one day they’ll remember that it only takes one experiment to disprove a theory. Maybe it will even happen one day soon. (They’ve recently come around on saturated fat, after all, after only half a century of misadventures) But meanwhile the loud and “official” conversation continues to sonorously repeat the disproven theories, for reasons that probably have as much to do with grant funding as actual belief.
Sweet Talk 
What if for each theory, there’s at least one experiment which falsifies the theory?
Then you keep looking. There’s no guarantee we actually know how something works.
The problem is that the endocrine system is too complex, and the secretion of each hormone too interrelated to the secretion of the others, for the story to be “hormones matter.” The fact of the matter is that calorie consumption influences hormone secretion, so you can’t separate the two things in the way that you’re doing.
Doubtless, hormones matter. But saying “hormones matter” is a lot like saying “money matters.” True, but now what?
Well figuring out all the things that affect hormones, and how to manage them as a system, is a very hard and complex task. Not easy! Weight loss is hard precisely because there are feedback mechanisms and limits to what you can do to affect your hormone profile.
But my larger point is about the conversations that nutritionists and “weight loss experts” have with each other, and how they continue to focus on discussing calories when this is (at best) a side show.
I think a big part of it is that we just don’t know how this all works. We can see how there’s no commonly prescribed and effective weigh loss treatment as evidence of that. But rather than admit they don’t know they keep going back to the explanation they understand even if its wrong.
The two main problems as I see them are, first: the weight loss, nutrition, and fitness industries are all dominated by advertisers rather than scientists. So much of the information we commonly encounter is advertising, as opposed to real information.
And second, hormone secretion is highly variable, not only across individuals, but within individuals. There’s no good way the average person has of knowing how much HGH has been secreted during their last evening’s sleep, and that’s going to affect how much IGF-1 is produced during the following day’s workout, as well as how insulin-resistant they are, at least until 11:00 AM. Both of these things will impact how much cortisol is produced from exercise. Etc. etc.
We don’t typically have access to our current hormone profile on a day-to-day basis. But that doesn’t mean we can’t observe long-term trends and make decisions based on what we do know about calorie consumption and exercise. Assuming there are no other hormonal problems, modest caloric intake is better than any extreme, and consistent, vigorous exercise is better than infrequent or inconsistent exercise. Common sense, basically.
Yeah, I don’t disagree with that. I would be thrilled if technology lets us measure these things in real time one day, but we can’t do that now. So my basic advise is to look at the things that, on average, have been shown to produce good hormone levels, and then try to do those things consistently. Sleep well, go to bed at the same time every day, don’t skip meals, do the right kinds of exercise, etc.
But that’s what I mean by focus on hormones, not calories. You should evaluate an exercise program based on what it has been shown to do to hormone levels, not how many calories it supposedly burns. The other parts of your life should be evaluated the same way.
Also, what YOU need to do to be healthy will be different than other people. You will have different tolerance levels for things. I, for instance, seem to be physically stressed by my environment rather easily. I gain weight when I’m stressed, and everything has to be just right for me to lose weight. But when I sleep enough, eat enough (food reduces stress), and exercise the right way, the weight comes off. It’s about managing my whole system, not burning 500 calories on a stationary bike and expecting to lose exactly 1/7th of a lb.