Anorexia and Dietary Fat: A Relationship of Estrangement

Part 1 of a series on the common avoidance of dietary fat in anorexia.

Posted Mar 04, 2020

Amazing to think that a few weeks ago I knew nothing of the wonders of porridge, and now I’m up to four bowls a day… That mixture of meat and cheese and cream and salt and starch was fabulous. The cheddar, especially, goes wonderfully glutinous – perfect with the fatty bits of pork. (from my diary, 12 October 2008, 4 months into recovery)

Why is actual, proper, “eating and body stuff is good now” recovery from anorexia so hard and so apparently rare, and how can you make it more likely to happen for you? 

Answering these questions is a lot of what this blog attempts to do. Every one of the 114 posts I’ve written so far is, one way or another, an attempt to articulate a part of an answer to them. From weighing scales to weightlifting, from motherhood to metaphorical thinking, from sex to Prozac to stress prevention, this blog has covered all kinds of contributors and obstacles to full recovery. One important thing I haven’t talked about much yet is about dietary fat.

One of the defining features of anorexia is selective food avoidance. Although in theory, one could starve oneself by eating small amounts of a wide and flexible range of foods, that rarely happens. Anorexic restriction typically involves reduction of variety as well as quantity of food, and it often involves consistent reduction of flexibility and spontaneity as well as systematic elimination of entire food groups. For me, the anorexic diet was a consistent series of drinks plus three rotating nightly menus, subject to period change but in each iteration feeling paradoxically immovable. And high-fat foods are high up the list of foods that tend to get cut out. My margarine was a ghastly low-fat thing (what does margarine have in it if not fat?), and my milk was skimmed and watered down. This feature of the anorexic diet is well documented, for example in these quotes from papers on the subject:

  • “While Anorexia Nervosa is a complex illness one highly stereotyped phenomenon is the persistent selection of low-calorie and low-fat food.” (Foerde et al., 2015)
  • “Patients with AN consume fewer calories and avoid dietary fat when compared to healthy controls.” (Mayer et al., 2012)
  • “Individuals with AN avoid high-fat, high-calorie diets.” (Nguyen et al., 2019)

To the extent that an anorexic diet provides nutrition, it often does so primarily via the macronutrient of carbohydrate, rather than fat or protein. Although protein may have positive attributes in the anorexic mindset, in their natural form proteins tend to come accompanied by fats, so they are easily lost by accident. There are various routes by which a nicely varied and relaxedly nutritious diet turns into a minimal-fat, lowish-protein, high-carbohydrate semi-starvation diet. For example:

  1. When anorexia begins as dieting, low-fat “diet” versions of food are an obvious choice: you might change your default milk to a lower-fat version, stop putting butter on your bread, or (if you’re in the US) maybe switch your whole eggs for whites, etc. Reduction in overall calorie intake and especially in fat intake has been found to be evident a year before illness onset (Lobera and Ríos, 2009). The fat elimination isn’t always across the board: in my anorexic diet, fat was shifted from the places where I considered it superfluous to the places where I wanted it: in the large quantities of chocolate and other sweet stuff I ate last thing before bed. 
  2. A common way to facilitate restriction without eliciting suspicion (e.g. from parents observing your changing eating habits and/or body) is to declare ethical or health reasons for eliminating foods, hence one reason for the high rates of vegetarian and vegan diets amongst people with anorexia (Bardone-Cone et al., 2012). It is possible to eat a high-fat vegetarian/vegan diet (e.g. by including decent amounts of vegetable oil, nuts, and fatty vegetables like avocados), but to the extent that your vegetarianism/veganism is piggybacking on your instincts towards disordered eating (as the study just cited found it usually does), eating low levels of dietary fat is both easy and likely when you cut out meat, or even more so if you cut out all animal products. In my case, vegetarianism preceded anorexia, but anorexia was certainly assisted in its survival by vegetarianism.
  3. As malnutrition sets in, dietary preferences change. I remember being amazed to discover that my habit of putting masses of salt on everything was a common one in anorexia, and that it probably derives from the body’s attempt to signal complex pervasive mineral deficiencies via a blunt sodium-specific craving. Alongside this kind of systematic micronutrient bias, macronutrient preferences also often shift in malnutrition, typically towards sugar (the most instant, easily digestible energy source for a malnourished body). And so, especially if food choices are also being made to maximise the pleasure-to-calorie ratio, the emphasis on carbohydrates and away from protein and fat continues to grow.

OK, but why, you may ask, does this matter? Who cares about fat? Isn’t it basically bad for everyone anyway, and shouldn’t eating more fat be the least of my worries if I’m trying to improve my diet in recovery?

First, no: fat – any kind of fat (except artificial trans fats, aka partially hydrogenated vegetable oils) – is probably not bad for anyone. I recommend Gary Taubes’s (2007) book The Diet Delusion  (UK) / Good Calories, Bad Calories (US) for an excellent deconstruction of the motives, methods, findings of the many research programmes that have suggested otherwise (for more recent papers on the subject, see e.g. Taubes, 2013; Harcombe et al., 2016, 2017; Forouhi et al., 2018). I’ve read quite a lot on this, and my conclusion is that any hysterical news story you read about how a sausage a day will reduce your life expectancy by a decade will be based on observational (i.e. correlational, not causal) data with by definition inadequate attempts to “control” for confounding variables (e.g. the fact that people who eat more saturated fat tend to engage in more risky behaviours than those who don’t).

Second, no: Adding in more fat should be one of your top priorities when considering how to improve your diet during recovery. Why? The second post in this miniseries will answer this question.

References

Bardone-Cone, A. M., Fitzsimmons-Craft, E. E., Harney, M. B., Maldonado, C. R., Lawson, M. A., Smith, R., & Robinson, D. P. (2012). The inter-relationships between vegetarianism and eating disorders among females. Journal of the Academy of Nutrition and Dietetics112(8), 1247-1252. Open-access full text here.

Foerde, K., Steinglass, J. E., Shohamy, D., & Walsh, B. T. (2015). Neural mechanisms supporting maladaptive food choices in anorexia nervosa. Nature Neuroscience18(11), 1571. Open-access full text here.

Forouhi, N. G., Krauss, R. M., Taubes, G., & Willett, W. (2018). Dietary fat and cardiometabolic health: Evidence, controversies, and consensus for guidance. BMJ, 361, k2139. Open-access full text here.

Harcombe, Z., Baker, J. S., DiNicolantonio, J. J., Grace, F., & Davies, B. (2016). Evidence from randomised controlled trials does not support current dietary fat guidelines: A systematic review and meta-analysis. Open Heart, 3(2), e000409. Open-access full text here.

Harcombe, Z., Baker, J. S., & Davies, B. (2017). Evidence from prospective cohort studies does not support current dietary fat guidelines: A systematic review and meta-analysis. British Journal of Sports Medicine51(24), 1743-1749. Full-text PDF here.

Lobera, I. J., & Ríos, P. B. (2009). Choice of diet in patients with anorexia nervosa. Nutricion Hospitalaria24(6), 682-687. Full-text PDF here.

Mayer, L. E., Schebendach, J., Bodell, L. P., Shingleton, R. M., & Walsh, B. T. (2012). Eating behavior in anorexia nervosa: Before and after treatment. International Journal of Eating Disorders45(2), 290-293. Open-access full text here.

Nguyen, N., Dow, M., Woodside, B., German, J. B., Quehenberger, O., & Shih, P. A. B. (2019). Food-intake normalization of dysregulated fatty acids in women with anorexia nervosa. Nutrients11(9), 2208. Open-access full text here.

Taubes, G. (2007). Good calories, bad calories. Anchor. / The diet delusion. Vermillion. Google Books preview here.

Taubes, G. (2013). The science of obesity: What do we really know about what makes us fat? An essay by Gary Taubes. BMJ, 346, f1050. Full-text PDF here.