Morality and Fat?

Last week NYU psychology professor, Geoffrey Miller got himself into hot water for posting a tweet that read: “Dear obese PhD applicants: if you didn’t have the willpower to stop eating carbs, you won’t have the willpower to do a dissertation. #truth.”


Aside from Professor Miller’s clear lack of understanding of nutrition (it’s not just about carbs) his tweet brings up an important point regarding obesity. We here in the US don’t often treat obesity solely as a potential health problem, rather we treat it is a moral issue. This is the result of prejudice rather than reason and is not helpful at all to anyone who is trying to lose weight. So to address the question of whether we should be viewing body weight as a moral issue we really need to step away from our cultural perceptions and look at our biology.

Body fat is just stored energy, if you consume more energy than you expend, you store it as fat. Our bodies have evolved over several hundred thousand years to survive in our environment; one of the ways that we did so was to adapt a way to store food energy, which allowed us to eat enough to fuel both our present need and to store energy for later when the food supply may be scarce, like during periods of famine. Our DNA doesn’t know that those of us in the affluent middle classes of the developed world have regular access to far more Calories than we need (1). By influencing us to eat more than we need, our genes allow us to store energy for the future, which enables proper development and guards against starvation (2). One of the things that happen when we diet and lose weight is that our resting metabolism slows down. In other words our bodies get more efficient and use less energy, which is certainly a good adaptation to prevent starvation, but a major pain for those of us who want to lose weight (3). Our bodies don’t only slow down our metabolism when we cut back on calories and lose weight, they also signal us to be hungrier (4). Furthermore, there have been over 600 genes identified that play a role in weight gain and obesity (5).

Now, while it is true that our bodies have evolved to hold onto the food that we eat and drive us to eat more than we need, I am not suggesting that biology justifies us in abandoning our efforts to improve our health by eating well and making positive lifestyle choices; we are thinking animals and it is now, as it always will be our own responsibility to take care of ourselves.  I am, however, suggesting that if you are a person who struggles with your weight, you have not morally faltered. There will always be those who disagree with me on this point but I am curious as to what their goals actually are with weight loss. It is probably not health.

According to historian and author Peter Stearns (6) the attitudes in the United States about fat result from our cultural need to morally compensate for excessive and wasteful consumerism. The problem with this line of moral reasoning is that it creates an unfortunate paradox, because our biological drive to eat is motivated by the need to store energy for later, which, contrary to being wasteful, is, from the physiologic perspective, actually a very thrifty thing to do. In the case of body fat, our cultural and biological perceptions of thrifty behavior are in dynamic conflict with each other.

Attaching morality to this problem can cause us to believe that unsuccessful attempts at weight loss are an indication of our own moral shortcomings, which can lead us to search for implausible or even harmful alternative solutions.  If, however, we keep in mind that weight loss is a physical and mental challenge that has nothing to do with our moral value it is possible to see that it is completely unwarranted to deem our lives unworthy simply because we have to struggle with something.

So to Professor Miller I say this: Get your biases and prejudices under control, Sir before you post foolish comments for the world to see. You are free to be a sanctimonious pedant in your private life but as an academic and a potential thought leader you have a responsibility to demonstrate better critical thinking.


  1. Statistics from the Food and Agriculture Organization of the United States. Data spreadsheet available at:…/FoodConsumptionNutrients_en.xls
  2. Tooby, J., Cosmides, L. 1990. “The Past Explains the Present: Emotional Adaptations and the Structure of Ancestral Environments.” Ethology & Sociobiology, 11: 375-424.
  3. Leibel, R. Rosenbaum, M., Hirsch, J. 1995. “Changes in Energy Expenditure Resulting from Altered Body Weight.” New England Journal of Medicine, March 9 332(10): 621-628.
  4.  Jhanwar-Uniyal, M., Beck, B., Jhanwar, Y.S., Burlet, C., Leibowitz, S.F. 1993. Neuropeptide Y projection from arcuate nucleus to parvocellular division of paraventricular nucleus: specific relation to the ingestion of carbohydrate. Brain Research 631:97-106. This study shows one of the mechanisms by which our bodies make us hungrier when calories are low an increase in a neurotransmitter called neuropeptide Y, which causes cravings for carbohydrate, a quick energy source, to increase. This stuff gets released in really high amounts during calorie reduction, which is, of course, interpreted by the body as starvation.
  5. Pérusse L, Rankinen T, Zuberi A, Chagnon YC, Weisnagel SJ, Argyropoulos G, Walts B, Snyder EE, Bouchard C. The human obesity gene map: the 2004 update. Obes Res. 2005 Mar;13(3):381-490.
  6. Stearns, P. Fat History: bodies and beauty in the modern west. 1997. New York, NY :New York University Press.