Genetics and Concern Trolling

By Brooke Troxell, Fattitude Intern

One of the major obstacles to the body positivity movement is a little thing us activists genetics-at-work2like to call “concern trolling”. If you don’t know what concern trolling is, it’s comments a lot of over-weight people get like: “Are you sure you should eat that?”; “Overweight people aren’t healthy”; “You are promoting obesity.” The main come back to this, that I have seen, is that health is personal and it looks different on everyone. Which is entirely true. But there is also more to the correlation between health and body weight than how many salads you eat per week.

As a scientist, I am surprised more people aren’t aware of it. What is this hidden factor I’m talking about? Genetics. Now, lots of people are vaguely aware that eating disorders such as anorexia, bulimia, and binge eating all have genetic contributors. But I’m not just talking about mental health disorders. Genetics

When I went to look up some specific articles to support this post, I originally typed in “genetics”, “body”, and “weight”. Over the last 10 years, 54,489 articles were written that had these three words in them. I picked three of the most relevant and up to date articles to peruse for this post. The genes that today lead to obesity first evolved to assist in efficient energy storage. Our early ancestors were hunter-gathers and did not have a steady supply of food all year long. Their genes needed to be able to store excess amounts of energy for when they couldn’t catch enough rabbits or find enough blueberries. However, since we have now mastered having all kinds of food available all the time, this gene is a contributor to living in a larger body.

Studies have found that 25-70% of variable weight (that is the weight that is not comprised of our vital organs and skeletal system) is under genetic influence. And it’s not just one gene that’s in charge of regulating excess body fat. There are over 600 chromosomal regions that work together to either store or burn excess energy. And your personal genes aren’t the only ones that matter.

Gut-BacteriaThe genetics of the bacteria in your intestines can influence your weight as well, as they are an integral part of nutritional absorption. There was a case of a woman who received a fecal transplant (sounds gross, but an actual beneficial medical procedure) from a healthy, but fat donor. The average sized woman who received this procedure  became very fat after her transplant. Now this one case isn’t enough to say for sure, but it definitely raises some interesting questions about the extent your intestinal bacteria can influence your weight.

The purpose of writing about the influence of genetics is not so we can all sit around and be sad and blame our hunter-gather ancestors for all of our problems. But rather to show that we can appreciate many different types of bodies. That because of our genetics (and our bacteria’s) health looks different on all of us. There’s no point in blaming short people for promoting a less-than-average-height lifestyle or people with brown hair for promoting the brunette lifestyle. Our bodies are more complex than we could ever really understand, so we should love them: no matter what shape, size, or color.


Russo, F. Lauria, A. Siani, Heritability of body weight: Moving beyond genetics, Nutrition, Metabolism and Cardiovascular Diseases, Volume 20, Issue 10, December 2010, Pages 691-697, ISSN 0939-4753,

Alfredo Martínez, Fermin I. Milagro, Genetics of weight loss: A basis for personalized obesity management, Trends in Food Science & Technology, Volume 42, Issue 2, April 2015, Pages 97-115, ISSN 0924-2244,

Rabah M. Shawky, Doaa I. Sadik, Genetics of obesity, Egyptian Journal of Medical Human Genetics, Volume 13, Issue 1, February 2012, Pages 11-17, ISSN 1110-8630,

Neha Alang and Colleen R. Kelly. Weight Gain After Fecal Microbiota Transplantation. Open Forum Infect Dis 2015 2: ofv004

*This blog post is the opinion of a particular Fattitude interns – and does not necessarily reflect the position of Fattitude, Inc.


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