Have you seen any studies about fat and acid indigestion? Like the idea that internal fat pushes on the stomach to make indigestion worse or something like that? A doctor told my mom that this was happening to her.

bigfatscience:

OK, I am unable to devote the time to look into the literature right now and post a bunch of links, I’m sorry. But I want to talk about this anyway because I have been told this same thing by doctors. And my research has led me to be  incredibly skeptical of this claim. 

It is true that there is a correlation between fatness and acid reflux. This means that fatter people are more likely to suffer from this condition. But as I have said many times here, correlation is not the same thing as known causation. Most importantly, and observed correlation between two variables – in this case, fatness and reflux – could be caused by other, unmeasured variables. 

This is so important for critically examining weight science because my experience reading through the literature concerning a host of health conditions tells me that these alternative explanations are very rarely considered or accounted for. Typically, when the correlation is observed, researchers cast about for some aspect of fatness that they  think might be responsible for the outcome, and voila, a causal theory is born! In this case, the causal theory is that stomach fat pushes up on the stomach and causes reflux.

Now here is where we use this knowledge to critically examine the claim that your mother’s doctor is making.

Do thin people suffer from this condition? Yes. So if their stomach fat is not causing the reflux, then what is? And why is that same cause not also thought to cause reflux among fat people? One of the most infuriating habits of the medical research community is to decide that fatness causes a given condition when fat people develop the condition whereas some other factor causes it among thin people. This makes no sense. It is more reasonable to assume that the same factor causes the condition for both fat and thin people, and that fat people are more likely to suffer from or exhibit that particular factor than thin people.

Here is one theory that comes from following this line of thinking. Did you know that acid reflux is very common among people who are recovering from a restrictive eating disorder? Chronic undernourishment damages the digestive system so that gastric emptying is slower, among other issues. So when people in recovery start eating more food, their stomachs cannot handle it and they experience terrible reflux. Fat people are more likely to suffer from restrictive eating conditions than thin people, and to engage in chronic lifetime dieting (aka starvation). We don’t actually know what effect that has on fat people’s digestive tracks… but isn’t it reasonable to propose that if chronic undernourishment causes digestive issues among thin people, it would have the same negative effect on fat people? And so the cure might be the same as well: Adequately nourishing your body by eating enough food regularly. 

And there are many other potential explanations for the correlation between fatness and reflux that simply are not being examined. My point is this: Be very wary when a doctor tells you your fat body is causing your issues or prescribes weight loss as a cure. I have yet to see a strong body of sound science to support this conclusion for any health condition I have researched.