Ah, calories! Let me count the ways . . . that calorie-counting is a limited, grossly over-simplified, and ultimately highly unproductive way of addressing weight or health.
According to some, the key to health and a healthy weight is making sure your calories in = calories out. This is called being “in energy balance,” and, according to the USDA 2010 Dietary Guidelines, this is what most Americans are “out of.” We are fat because we eat more calories than we need—whatever that means. And the only way to NOT be fat is to “eat less and move more.”
Sounds simple enough. So why doesn’t it seem to work all that well?
Let’s start with the basics:
- When a person decreases their “energy in,” that person’s “energy out” also goes down. For example, take Ancel Keys’ early starvation experiments.
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When a person increases their “energy out,” that person’s “energy in” goes up. For example, take my 6’7″ basketball- & soccer-playing nephew out for dinner.
[Shameless Auntie plug: check out his latest endeavor, “Kicking across Carolina“]
Eating less and moving more is like breathing underwater: not impossible, but somewhat awkward and unnatural. Some turtles can breathe underwater through their butts; some people can eat less and move more. For a lot of us, we are as likely to be as successful at the former as we are at the latter.
Turtles can, can you?
What? you say. But it’s SO obvious. People who eat less, weigh less; how much simpler could it be?
Except that we don’t really have a lot of data that demonstrates that this is the case. Oddly enough, this is a cross-cultural, age-independent, apparently universal, problem.
For example, for these American Indians, higher BMI is associated with lower calorie intake.
From: Xu J, Eilat-Adar S, Loria C, et al. Dietary fat intake and risk of coronary heart disease: the Strong Heart Study. Am J Clin Nutr. 2006 Oct;84(4):894-902.
In this Mediterranean population, higher BMI is associated with lower calorie intake.
From: Casas-Agustench P, Bulló M, Ros E, Basora J, Salas-Salvadó J; Nureta-PREDIMED investigators. Cross-sectional association of nut intake with adiposity in a Mediterranean population. Nutr Metab Cardiovasc Dis. 2011 Jul;21(7):518-25. Epub 2010 Mar 9.
In these kids, higher BMI is associated with lower calorie intake.
From: Qureshi MM, Singer MR, Moore LL. A cross-sectional study of food group intake and C-reactive protein among children. Nutr Metab (Lond). 2009 Oct 12;6:40.
Yeah, in these kids too.
The trend continues as kids become teenagers. Strangely, the teens who move more, eat more; the teens who move less, eat less. And, surprise, higher BMI is associated with lower calorie intake. Hmmm.
From: Patrick K, Norman GJ, Calfas KJ, et al. Diet, physical activity, and sedentary behaviors as risk factors for overweight in adolescence. Arch Pediatr Adolesc Med. 2004 Apr;158(4):385-90.
As you may be aware, some researchers do have an explanation for this phenomenon: Fat people lie. That’s certainly a much more convenient explanation than examining the possibility that there is more to nutrition metabolism than “calories in, calories out.
Sadly, this lying stuff apparently starts young. In this study, the researchers concluded that the 9-year old girls under investigation are apparently lying about how much they eat:
“Importantly, this study found that the positive association between energy intake and adiposity was observed only after excluding implausible energy intake reports, but not in the total sample which included implausible reporters, the majority of which were overweight children who under-reported energy intake.”
This means there is no association between calories and overweight in the general sample. An association is only found if the researchers exclude “implausible” intakes of overweight children who “under-report” what they eat. The researchers determine which intake levels were “implausible” because they know how to calculate how much fat kids are supposed to be eating:
“Physiologically plausible reports of energy intake were determined by comparing reported energy intake with predicted energy requirements.”
In other words, if the chubby little girls don’t eat as much as the researchers think they should be eating, as calculated using formulas that are notoriously inaccurate, then the conclusion is that they (the girls, not the researchers) are lying.
Luckily, the folks at the USDA are totally on top of this issue and can give us a clear explanation of what is going on:
“One would expect to find a strong positive association between caloric intake and a measure of body fatness, such as the body mass index (BMI).”
Yes, one would, if one thought that all that really matters is how many calories go in and how many calories go out.
“However, nutrition studies using self-reported food intake data, such as the CSFII data, have failed to find such an association, . . . ”
Y’don’t say? Hmmm. Wonder why that could be? Maybe nutrition is more complicated than a simple energy balance equation?
” . . . primarily because overweight persons tend to underreport intakes to a greater degree than healthy weight persons.”
Oh right, I forgot. So, they’re all lying? Native Americans, people in other countries, old people, young kids (or maybe their parents)?
“Also, at any given time, overweight persons may be on weight-loss diets. ” [emphasis mine]
Ohhh. That might help explain things. In other words, fat people either do not have the moral fortitude to be honest with themselves or anyone else about how much they eat, or they are—bravely, in the face of ridiculous odd against them—reducing the number of calories they eat.
In a study examining the association between calorie intake and BMI in women who are dieting, the investigators found, big surprise, an inverse association between BMI and calories (Ballard-Barbash R, Graubard I, Krebs-Smith SM, Schatzkin A, Thompson FE. Contribution of dieting to the inverse association between energy intake and body mass index. Eur J Clin Nutr. 1996 Feb;50(2):98-106.).
In other words, higher BMI is associated with lower calorie intake. The researchers conclude that:
“Intermittent energy restriction appeared to be a significant factor in the reduced energy intake reported among overweight women in this sample.”
The women aren’t lying; they’re dieting. Maybe they’re doing both!
Two-thirds of Americans are overweight or obese. Apparently, two-thirds of Americans are either lying or dieting, or maybe both.
If you are a lying fat person, we can’t really draw any reasonable conclusions from the epidemiological data we gather about your eating habits. Furthermore, weight loss programs based on “calories in, calories out” are not likely to help you because you lie about what you eat anyway.
If you are a dieting fat person, we can’t really draw any reasonable conclusions from the epidemiological data we gather about your eating habits. Furthermore, weight loss programs based on “calories in, calories out” are not likely to help you because conventional weight loss programs are not likely to help anyone.
It is just a thought, but perhaps is it time to think about whether there are other things—besides normal human metabolism–that may affect “energy balance.” Quick brainstorm list off the top of my head:
- genetics
- epigenetics
- environmental toxins
- hormonal status
- lifestage
- disease state
- medications
- infection/inflammation
- sleep patterns
- stress
- gut flora
- and last but not least, the food you eat
What? you say. The food we eat?
If you want to be obsessed about calories going in and out, it makes sense to figure out which foods might cause fewer calories to go in and which food might cause more calories to go out. We don’t have all the answers—and it is my personal perspective that individual response is what matters most—but, here are a few clues:
In this study, participants who ate eggs for breakfast (with no other deliberate dietary changes) consumed 400 fewer calories over the course of the day than the participants who ate bagels, i.e. calories in went down.
From: Ratliff J, Leite JO, de Ogburn R, Puglisi MJ, VanHeest J, Fernandez ML. Consuming eggs for breakfast influenced plasma glucose and ghrelin, while reducing energy intake during the next 24 hours in adult men. Nutr Res. 2010 Feb;30(2):96-103.
In this study, when participants consumed a diet with reduced carbs and increased fat, resting and total energy expenditure tended to go up compared to when the same participants consumed diets with higher carb and lower fat content, i.e. calories out went up.
From: Ebbeling CB, Swain JF, Feldman HA, Wong WW, Hachey DL, Garcia-Lago E, Ludwig DS. Effects of dietary composition on energy expenditure during weight-lossmaintenance. JAMA. 2012 Jun 27;307(24):2627-34.
So, strangely enough, simply by choosing foods that are specifically NOT recommended in the current low-fat, low-cholesterol, high-carbohydrate diet promoted by the USDA/HHS, you may be able to alter your “energy balance” so that there are fewer calories coming in and more calories going out, without having to change anything else.
It’s time to quit condemning 9-year-old girls to a lifetime of hunger and frustration with “calories in, calories out” dieting, or accusations about them lying about what they eat, or both.
To paraphrase the immortal words of Dr. Suess:
“Calories in, calories out” will you please go now!
The time has come.
The time is now.
Just go.
Go.
Go!
I don’t care how.
“Calories in, calories out”
I don’t care how.
“Calories in, calories out”
Will you please
GO NOW!
Next up: The Mobius strip of policy & the future of nutrition
Eathropology 
I’m finally replying to this thread, although there doesn’t seem to be a reply button after your last post. 🙂 Sorry about the delay, I just stumbled across the link in my blog stats and remembered our conversation.
I’m a fan of protein, and it’s the one macro I really encourage people to have a target for (1 gram per pound of body weight). The other macros I find are much more a matter of taste and personal physiology. So I wouldn’t look askance at your protein studies.
Personally, my hunger and, especially, satiety signals have never been very trustworthy. I honestly think it’s biological. I have two kids and one of them has GREAT appetite regulation and the other will eat until she throws up if you let her. She’s always been like that. Never really gets an ‘I’m full’ signal. Just like me. Thoughts on that? I’ve experimented with lots of macro ratios (including several iterations of low carb) to see if there’s a magic ratio that will give me the full signal and so far no dice. Being aware of calorie intake has been a blessing in teaching me how much food I need to function optimally (a lot!) and how to put together balanced meals to meet all my nutrient needs. Calorie tracking certainly isn’t for everyone but I honestly don’t think I’d have been able to turn my health around without it.
And yes, you did just write the newest bestseller. 🙂
Protein is the one non-negotiable macronutrient. But I think quality and timing of protein are as important as absolute amount. One of the issues that Americans seem to have is that we eat so little protein for breakfast that we are “chasing” our protein needs all day long. Plus, plant-based protein can be a lot harder for some folks to absorb, so people think they are getting protein, but it is going through rather than in them! I knew someone who drank soy protein shakes for breakfast, then had to sprint to the bathroom afterwards. She wondered why she was starving an hour later after “getting” plenty of protein for breakfast.
I can only trust my huger/satiety signals if I am otherwise well nourished–and for me that boils down to protein intake. I suspect that for other folks, another component of the diet may be a stronger driver of food-seeking. However, there is without a doubt a genetic/epigenetic component to appetite regulation. I have kids like yours: one with an especially fine-tuned stop signal, and one who eats until the food is gone. For my son with no appetite “brakes,” reducing carbs helps limit crave-worthy foods and getting sufficient protein assures me he’s not otherwise depriving his body, but neither is a magic bullet for limiting overall intake. I had very different pregnancies with each child. My overeater was born during my most low-fat vegetarian phase and it was a very difficult pregnancy. My appetite-regulator was born after my OBGYN insisted that I eat protein with every meal (in response to my previous nightmare pregnancy) and it was pretty smooth sailing physically even though other things in my life were falling apart at the time. Was it the protein? The fat? Lower carbs (which happened by default)? Something else entirely? I don’t know, but I suspect that future research around epigenetics will help answer this question.
For patients who needed intake limits, we used portion control (with specific amounts and weights) rather than calorie counts–it is possible that calorie counts may have been more effective, but then you have to weigh or measure to get those anyway. One of my main concerns with calorie counting is that it seems to drive people in the direction of packaged foods, simply because the calories are already counted for you. This would seem to create some tension between a whole foods approach and the metrics needed to track calories. Is this something you find is true of your readers?
I truly do not have any simple answers for individuals; each case is different. My main concern is our public health recommendations. While any given individual may need to count calories, the “eat less, move more” approach based on calorie-counting is inappropriate for a population-wide prescription. Too much potential for failure and unintended consequences, such as a nation full of disordered eaters. I would much rather our government policy focus on getting essential nutrition and leave the individualized assistance for helping individuals adjust intake, exercise, supplements, etc. to caring and knowledgeable people like you.
Jeez. This is great stuff. Thanks so much for taking the time to write this.
In my research on Wilbur Olin Atwater, the guy who thought up the food calorie, it seems that he made so many ‘adjustments’ to the numbers that they really don’t mean anything to a person. Also – as he experimented on people eating diets from over 100 years ago, I question their relevance today – and am under the impression that his body of work has never really been updated – do you know if this is true?
Anyway, perhaps to a public health researcher looking at populations, the food calorie might have some use, but like the BMI, it’s a travesty to foist calories on people as a way to measure food intake and expect it to be of any worth.
I’ve also wondered if caloric absorption is impacted by the nutrients you intake. I imaging that would be covered in your list above under ‘gut flora’, but I’m curious about what situations might reduce nutrient absorption.
Anyway – forgive the rambling – I just love the stuff you’re putting out here and can’t wait for more.
You ask some really good questions. One of the very few serious shortcomings in my nutrition education at UNC-Chapel Hill is that I had to go outside of the department to get anything more than a cursory glance at the history of nutrition in America. I really think a Food Culture class should be part of our core curriculum. So I know little about Atwater, except that he was one of the first to say “eat more protein and fewer carbohydrates.”
In terms of public health, I’m not sure the concept of calorie is even useful there. Our collection instruments for food intake are notoriously inaccurate; we assume that the 2/3s of population that is overweight/obese will “underreport” intake (in which case, why do we bother asking?); and calories–as you clearly know–have little to do with nutrition. My favorite biochemistry book doesn’t even list the word “calorie” in the index.
There are a lot of situations that would reduce nutrient absorption, namely anything that increases transit time. Fiber for instance, or vibrio cholerae. Things that bind nutrients–phytates–can slow or prevent absorption, but that frequently applies to vitamins and minerals that we don’t think of as having “calories” in the first place.
In case you missed, and in a fit of shameless self-promotion, see Why Calories Count Fo’ Shizzle for another look at calories.
You wrote: For example, for these American Indians, higher BMI is associated with lower calorie intake.
But the included table completely contradicts that. Confusing. On the Mediterranean example the BMI basically went up with the ratio of women to men while the calories were very very similar. The more women their were in the group the higher the BMI was.
Once you move onto the kids the tables appear to support what you are saying.
Thanks,
jesse
For the Native American group there are two different age ranges. In the 47-59 year old range, the average BMI in the CHD group is 31.8, with calorie intake of 1940; in the no CHD group the BMI is 32 with a calorie intake of 1916. These are not hugely different BMIs or intake ranges really, but if folks are eating more calories, they should weigh more, right?
Excellent point about the gender ratios for the Mediterranean group! I wish I’d made it. But, if all we are dealing with is calories in/out, it shouldn’t matter. Instead, what it looks like is that being female may mean that you’ll have a higher BMI even if you eat fewer calories.
Looks like a popular topic. Robb Wolf tweeted this article earlier, posting it here since it jibes: http://blogs.scientificamerican.com/guest-blog/2012/08/27/the-hidden-truths-about-calories/?WT.mc_id=SA_syn_HuffPo
Calories have been on everyone’s mind these days. I think Go Kaleo has a nice piece on this topic too. Although I could nitpick about a few details, she’s right on the money when she says: “All that black and white thinking has got people believing a false dilemma: It’s EITHER ‘calories in vs. calories out‘ OR ‘the kind of calories you eat‘ that matters!” I’m down on the calories in/calories out paradigm because it is so limited in scope, but I would agree with her that–in many cases, although there may be metabolic exceptions as there always are–calories can matter. My understanding of the biochemistry is that there are two necessary aspects to weight gain: excess calories to store (although we seldom know how to measure or even estimate what we mean by “excess”) and the insulin signal that provides the mechanism for storage to take place. For weight loss to take place, we have to figure out how to not create a metabolic situation where these two factors are at play AND we have to figure out how to convince our body to reverse the fat-storage process (which may be a very different matter entirely, not just one of eliminating excess insulin-stimulating carbohydrate foods). Some people can reduce overall calorie intake (although this usually also involves a lowering of carbohydrate foods that stimulate insulin release); some people can just reduce their carbohydrate food intake (although this usually also involves lowering calories available for storage); some people have to do both–deliberately and carefully. The trick is how to do this without 1) inducing willpower-withering hunger pangs, 2) depriving the body of essential nutrition 3) creating other metabolically-unfortunate side effects/consequences. The answer will not be the same for everyone.
I’m curious about the points you would nit pick with me. Really. I know it’s more complicated than I laid out, and my intended audience is people who are generally metabolically healthy, so I tried to make it as easy to ‘digest’ as possible without oversimplifying to the point of being inaccurate. Most of my readers aren’t interested in scientific studies and learning about the intricacies of endocrine function; HOWEVER, if there’s a way I can incorporate more specifics without making it too complicated, I’m definitely for it! So lay it on me. 🙂
Hmmm. I get what you’re trying to do, it’s a tough balance & something I’m trying to figure out as well: How do you make it easier (rather than tougher) for people to reach their health goals, without oversimplifying things to where it just gets dopey? I guess when I see statements like “take in fewer calories than you burn,” I have flashbacks to clinic days trying to convince women that, once they got the carbs they didn’t need out of their diet and made room for the protein they did need, the whole picture of what your taking in vs. burning changes. They would still be freaked out about calories when their metabolisms were upregulating (many of these women would add lean body mass without even doing resistance training, once their bodies got enough protein). So–like you–I’d try to get them to focus on adequate amounts of high-quality protein (for my purposes, that’s approx 4 oz, more or less depending on size/activity) at each meal, plus the non-starchy veggies, and see how that went first. I would almost always recommend 1 tsp fish oil and a multivitamin as a way of getting to a baseline level of adequacy of essential nutrition, to reduce the possibility that some micronutrient deficiency is driving appetite (salt restriction can do this too). With the satiety effects of protein coupled with the fact that–as I loved about your post–most of these women were already UNDEReating, I didn’t have to tell them to watch calories; they would usually complain that I was trying to get them to eat too much food! The exceptions were post-menopausal women and cheese lovers! With the PMW, it was always a tricky balance between weight loss and nourishment. They seemed to need “just enough” food, but no more/less. The ones who were active, of course, did better. With the cheese lovers, they had to limit portions, or not eat it at all. [See, didn’t I just write the next best-selling diet book? Protein, veggies, adequate nutrition, not too much! Give me money!!!]
I also know that the equations that are used to calculate energy needs are often wildly off-base, especially for overweight/obese people, so I don’t really trust them, but I guess my biggest issue with “counting calories” is not the calories part, but the counting. It seems to take people out of their bodies and into their brains. I’d rather have someone think about hunger and fullness and feeling satisfied and “fed”–and how to get there eating foods that provide nourishment first. But I will fully acknowledge that people can and do overeat calories & there is not an easy way to tease apart getting nourishment from getting calories. Some people, you said you’re one of them, don’t seem to have good “stop” signals and in that case, calorie counting may be absolutely necessary, but I would use it later on down the road, if someone was not getting to their goal otherwise. Not because it doesn’t work or doesn’t help, but because if self-regulation is possible, I’d prefer to focus on that first.
BTW, I can dig out the protein info for you if you’re interested. It’s sort of fascinating to me that people at different labs have come up with similar numbers for protein synthesis threshold (using muscle as a proxy measure), which is about 30g per meal. Less than than & little protein synthesis takes place; more than that has no added effect. Young men seem to have more protein “wiggle” room; older people seem not to. And for whatever reason, steak and eggs seem especially beneficial for older folks 🙂