Home > musing, statistics > What makes us fat

What makes us fat

August 27, 2012

I recently finished a book that made rethink being fat, and the cause of the worldwide “obesity epidemic”. Rethink in a good way.

Namely, it suggested the following possibility. What if, rather than getting fat because we are overeating, we overeat because we are getting fat? Another way of thinking about this is that there’s something going on that makes us both store fat away and overeat – that they are both symptomatic of some other problem.

In particular, this would imply that the fact of being fat is not a moral weakness, not a mere lack of willpower. Since I long ago dismissed the willpower hypothesis myself (I don’t seem to have trouble with other aspects of my life which require planning and willpower, why do I have so much trouble with this even though I’ve seriously tried?), this idea comes as something of a “duh” moment, but a welcome one.

To get in the appropriate mindset for this idea, think for a moment about all of the studies you hear about feeding animals such as rats, rabbits, monkeys, pigs, etc. different diets, and noting that sometimes the diet makes them super fat, and sometimes it doesn’t. Sometimes the animals are bred to have a genetic defect, or a pituitary or other gland is removed, and that has an effect on their fatness as well. In other words, there’s some kind of internal chemical thing going on with these animals which causes this condition.

Bottomline: we never accuse the fat mice of lacking will power.

So what is this thing that causes overeating and fat accumulation? The theory given in the book is as follows.

Fat cells are active little chemical warehouses which accept fat molecules and allow fat molecules to leave in two separate (but not unrelated) processes. Rather than thinking of fat as being stored there until the moment it is needed, instead think of the flow of fat molecules both into and out of each fat cell as two constant processes, so it’s actually better to consider the rate of those flows, the inward rate and the outward rate.

Suppose the outward rate of the fat molecules is somehow suppressed compared to the inward rate. So the fat molecules are being allowed into the fat cells just fine but they aren’t leaving the fat cells easily. What would happen?

In the short term, this would happen: lacking the appropriate amount of energy, the overall system would feel internally starved and get super hungry and quickly cause the animal to overeat to compensate for the lack of available energy.

In the longer term, the number of fat cells (or maybe the size of the average fat cell) would increase until the energy flow is sufficient to satisfy the internal needs of the system. In other words, the animal would gain a certain amount of weight (in the form of fat) and stay there, once the internal equilibrium is reached. This jives with the fact that people seem to have a certain “set point” of weight, including overweight. Indeed the amount of fat an animal has in equilibrium allows us to estimate how suppressed the outward flow of energy is.

What causes this suppressed outward rate? The book suggests that it’s elevated insulin. And what causes chronic elevated insulin? The book suggests that the main culprit is refined carbohydrates.

In particular, the author, Gary Taubes, suggests that by avoiding refined carbohydrates such as flour, sugar, and corn syrup, we can bring our insulin levels down to reasonable levels and the outward rate of fat from fat cells will no longer be suppressed.

Not everyone reacts in exactly the same way to refined carbs (i.e. not all insulin responses are identical) and scaled definitely matters, so eating 180 pounds of sugar a year is worse than 90 pounds a year, according to the theory. Moreover, things get progressively worse over time and it takes about 20 years of carb overloading to have such effects.

It’s easier said than done to avoid such foods as an individual living in our culture (nothing at Starbucks, nothing at a newsstand, almost nothing at a bodega), but one thing I like about this theory is that it actually explains the obesity epidemic pretty well: as the author points out, massively scaled refined carbohydrates have only been consumed at such rates for a short while, and the correlations with weight gain are pretty high.

Moreover, and I know this from personally avoiding most carbs for the past 6 months (which I started doing for another, related reason – I hadn’t read the book yet!). I’ve lost weight easily, and I haven’t ever been hungry, even compared to what I used to experience when I wasn’t dieting at all. According to the theory, my fat cells are releasing fat easily because my insulin levels are low, which means I don’t have internal starvation, which in turn explains my complete lack of hunger.

Also in the book: he claims we don’t actually know eating saturated fat raises cholesterol, nor that high cholesterol causes heart disease except when it’s super high, but then again it also seems to be bad to have super low cholesterol.  I gotta hand it to this guy, he’s not afraid of going against conventional wisdom, at the risk of being ridiculed, which he most definitely has been.

But that doesn’t make me dismiss his theories, because I’m pretty sure he’s right when he says epidemiology is fraught with politics and bad selection bias.

It’s certainly an interesting book, and who knows, he may be right on some or all scores. On the other hand, maybe it doesn’t matter that much – not many people want to or are willing to avoid carbs, and maybe it’s not environmentally sustainable, although I don’t eat more meat than I used to, just more salad.

We are now ruling out the idea that people don’t exercise enough as the cause for being fat, and as we’ve attempted to follow the advice of the so-called experts, everyone seems to just get fatter all the time. As far as I’m concerned, all conventional bets are off.

Categories: musing, statistics
  1. August 27, 2012 at 10:01 am

    I haven’t read the book but came across a review of it a few days ago and plan to read it soon. It sounds like the main idea is to avoid refined carbs in order to regulate insulin production -this is the same message being touted by Dr. Atkins some 15 years ago, among others. He too was ridiculed for espousing this idea, only to be proven right by a mounting body of studies and countless personal anecdotes supporting his ideas.


  2. Steve Stein
    August 27, 2012 at 10:22 am

    Y’know, I found that if you consume fewer calories, you lose weight! I did it with Weight Watchers, but I don’t think you need their method to do it. Changing a few habits did it for me – Cheerios and fruit for breakfast instead of bagels or danish. Fruit for snacks instead of Doritos. Water or unsweetened ice tea instead of Coca Cola. A bit of portion control. In six months I had lost about a pound a week, and I’ve kept it off.

    I found that just keeping a written record of what I ate helped a lot.


    • August 27, 2012 at 8:38 pm

      Steve, there’s a reason Weight Watchers never publishes its success rate.


      • Julie
        August 28, 2012 at 8:06 pm

        The people I know who lost a lot of weight and kept it off ALL followed weight watchers. Every one.


  3. Wendy G
    August 27, 2012 at 10:57 am

    Steve, that’s great that that worked for you, but honestly if it were just that simple, those changes would work for larger groups of people – larger than just 1, I mean. The fact is, diets (including the ‘lifestyle change’ variety final 95%of the time. And most of the time, they actually end up making people fatter. It is waaaaay past time to stop villains zing heavier people.
    Taubes has done some interesting work on the diet side, but on the diet industry side, and the science of dieting, I highly recommend The Obesity Myth by Paul Campos.


  4. JSE
    August 27, 2012 at 11:14 am

    “Not everyone reacts in exactly the same way to refined carbs”

    This is, of course, the main point, just as not everybody reacts in exactly the same way to calorie restriction or to exercise. If there’s a population of people who are highly sensitive to sugar intake, that’s worth knowing, even if most people who go on low-carb diets don’t lose. I cut off all bread, pasta, fruit, sugar for a month and lost no weight, felt no different, was no more or less hungry, etc. On the other hand, in the past, I’ve used calorie-restrictive diets and lost 10 lb in two weeks, which took a couple of years to come back.

    People are different!


  5. August 27, 2012 at 12:28 pm

    I’ve had success with reducing carbs and not worrying about eating higher-quality saturated fats over the past year – after decades of doing exactly the opposite. So it’s easy for me to accept this theory. The 20-year trigger for excess carb consumption to impact fat storage was about right for me too.

    Getting rid of excess carbs was hard at first, but once I found a good low-carb breakfast, the rest of the day was much easier. I’d agree that keeping insulin levels from spiking seems to be the key.

    The Wheat Belly book by William Davis has observations which broadly agree with this theory – although he’s not real hot on whole wheat bread and some other less refined grains. The book convinced me to try reducing refined sugars/wheat and I’m glad I did. It’s not just the weight, I just feel better and not hungry all the time.

    U.S. diets have increased carbs relative to fats over the past few decades. As you observe, the obesity results seem consistent with this theory.


  6. August 27, 2012 at 3:25 pm


    Gary Taubes has a lot right, but others have expanded significantly. Check out the blog called Hyperlipid by Peter Dobromylskyj. There is no doubt he puts out the best and most innovative ideas.

    The vast majority or nutritionists or doctors should be ashamed of themselves for using thermodynamics laws in an attempt to provide insight for losing weight.

    Exercise to burn calories is a bad idea, but weightlifting and such should help. For the latter, you are creating a situation where calories are partitioned away from fat cells. Typically the leaner and more musclular one is (assuming that person isn’t starving or something), the easier it is to stay that way.

    Regarding epidemiology or observations, Ned Cock of The Health Correlator always does his own statistical analysis of studies that pass as science, while covering the study’s flawed methods and such.


  7. suevanhattum
    August 27, 2012 at 5:17 pm

    Not for weight reasons, I avoided all grains but rice and all sugar including fruit for 3 months last year. (I was trying to deal with candida.) I ate as much fat as I wanted, trying to feel full. (Breakfast was the hardest to get used to. I often had rice and beans with my fried eggs.) I began to feel full without my comforting bread products. And I lost 20 pounds.

    I’ve gained much of it back, but I’m trying to move toward less refined stuff in my diet, because it did feel good to be carrying less weight around.


  8. August 27, 2012 at 6:45 pm

    Last year I came across an article in the NY Times entitled, ‘Is Sugar Toxic’, By GARY TAUBES.
    I read the article, watched the Robert Lustig’s accompanying YouTube video, where he discusses
    his theory about how sucrose, fructose, corn syrup, etc. are metabolized.

    Then, I gave up sugar.
    I gave up sugar in coffee, I gave up maple syrup, dried fruits, yogurt with added sugar and all deserts for 3 months. The rest of my diet and exercise I kept constant. I lost 20lbs (162-142).

    As soon as I restarted eating low-fat yogurt with sugar, I gained 2-3 lbs. When I stopped,
    the weight came off. Now I eat small amounts of sugar and after a year I stabilized at 148lbs.

    Everyone’s body reacts differently, so you won’t know if sugar is causing the body to store fat unless you try it.

    Good Luck!


  9. August 27, 2012 at 6:47 pm

    Here’s the link to the article ‘Is Sugar Toxic’, by Gary Taubes.



  10. libertarian by default
    August 27, 2012 at 8:19 pm

    +1 for Taubes and low-carb and I feel that reading GCBC added years to my life. I immediately lost 30lbs (eventually 65, without ever feeling “hungry”) but even more strikingly I was cured of chronic colds. I basically haven’t had a cold in 4 years after being sick all winter for my entire life prior to low-carb. I started out following Atkins but switched to more of a primal/paleo diet (i.e. real foods, avoiding franken-chemical artificial sweeteners, avoidance of vegetable oils).

    Regarding the farce of “calories-in-calories-out” I recently gained 20 lbs almost overnight without a change in diet due to prolonged (very) poor sleep. There is no doubt in my mind that this is due to hormonal changes as opposed to a sudden caloric surplus (more likely is that I was always in caloric surplus but the “unused” calories were not being shoved into fat cells).

    Some of the ideas in GCBC are now outdated or overstated (we’re just beginning to understand differences among certain subsets of the population) but see continuing work at http://eatingacademy.com.


  11. Amit Chokshi
    August 27, 2012 at 9:32 pm

    It’s calories in, calories out and not so much as willpower as it is planning. most people don’t have any established baseline in terms of their avg daily caloric intake. You need to establish that and then slowly tweak it. clean up a few things like bad carbs and slop and be gradual in cutting down calories. start with cutting out 300 calories per day for a few weeks and see how you feel. many diets people follow or exercise are a huge shock to their system. our bodies hate shock so when that happens, we secrete all sorts of hormones to protect us. so libertarian, lack of sleep results in an increase in cortisol which is a hormone that can increase fat storage. over exercise or too intense of a diet causes the release of cortisol as well. lack of sleep also causes the brain to crave glucose/sugar so if you mistime your intake of those sugars you will crank up your insulin at the worst time and end up hoarding fat.

    exercise and diet combined are good. the problem with “more” exercise is that most people that are not coming from an athletic background or are far removed from exercising regularly think that they are doing way more exercise than they really are from a caloric standpoint and then overeat. hit the stairmaster for example at a gym at say level 11. 20 min of that is hell but it only burns about 300-350 calories for me in those 20 min. 300 calories is like a friggin bagel…when you start doing more exercise and tracking those things you really start to understand/quantify what everything you put in your body is in terms of required exercise to burn off.


  12. August 27, 2012 at 10:31 pm

    I disagree on only one point — refined or not, carbs are carbs, and one should avoid all of them. As for coffee, I enjoy it every morning with heavy cream (no lactose) and diet sugar. Another thing, I have had diabetes for thirty years and taken insulin for twenty. I no longer put out body insulin (although I have type 2 diabetes, taking insulin causes you not to produce it, as was explained to me by a Diabetologist). However, once I limited myself to 100 grams of carbohydrates a day, the insulin (fast acting and slow acting) I need to keep my blood sugar down was cut approximately in half. So it’s the same argument you make except with insulin INJECTIONS!


  13. August 28, 2012 at 10:25 am

    I don’t know enough about Taubes’ book, but I do suggest you take a look at Seth Roberts’ The Shangri La Diet. It makes sense to me, in an armchair biologist kind of way, and better yet, it worked. For me.


  14. August 28, 2012 at 9:25 pm

    I wouldn’t blindly ignore exercise — it worked for me (a quick 20 lbs off, 6 years ago, and it stayed off), and I hate to diet. What works for me is to make it unavoidable — ride my bike to work a minimum of twice a week, plus errands and dinking around down. That’s a guaranteed 50 miles per week, on a big heavy cargo bike, so call it 4 hours of exercise, or 2500 kCal. I nudge it up in the summer, and I temporarily lose a couple more pounds, and endure spells of feeling very, very hungry.

    I’m sure part of it is just luck in finding something that works for me, but I think it helps that it’s hard to cut corners; if I quit early, I don’t get to work, or I don’t get home.


  15. Jason Tang
    August 29, 2012 at 4:09 am

    The last article you linked bugged me because the study concluded that the Hazda hunter-gatherers ingested less energy, but it didn’t actually measure how much energy they ingested. And of course I’m biased against its conclusion, because of my personal experiences. I went from no exercise to 20-40 minutes of moderate exercise most days, and that along with cutting down on junk food and fast food has helped me lose 40 pounds over a couple of years.

    So maybe it’s appropriate to say that some exercise is good, but more exercise doesn’t necessarily mean more weight loss?

    It seems that the problem with our approach to health is that we want to reduce everything down to one variable, and then adjust that variable to some extreme. We also assume everyone is the same. It’s no wonder then that things don’t always work.

    Finally, I think that in order to change habits (be they eating and/or exercise), people don’t need willpower as much as they need role models. The only time we hear about people losing weight is when they are selling us a product. Either weight-loss advice is so specific that it can’t possibly work for everyone, or it’s so vague that most people can’t figure out how to put it into action. So what is it actually like to cut back on unhealthy foods? What meals can you actually eat? How do you actually cut down on portion size? What do you do if you don’t have time or energy to cook for yourself? People are hungry for answers to these questions that work for them.


  16. September 11, 2012 at 1:23 am

    This is the best thing I’ve ever read on will power and weight loss… now to make a formula for it!

    and since you’re into math, and like lines and graphs and things, I’ve found the best way of tracking calories without tracking calorie is the “hackdiet” – engineer, mathematician, IT guy, it’s what’s making me lose and keep on track even when the variables go up and down the long term trend is in the right direction!


    I got really tired about all the hype around dieting, and gaining and losing and did a whole bunch of research on it before I started. It’s been very illuminating.


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