FGF21 Gene Variant: Increased Sweet Consumption

Is it possible to eat more sweets and have a decrease in fat?

A new study recently published in the journal Cell shows a genetic link to having a sweet tooth, but this sweet tooth gene comes with a nice twist: it causes a slight decreased in fat mass.

I may have to dub this the ‘not fair!’ gene variant since I don’t have it.

The gene in question is FGF21, which codes for a hormone that is created in the liver. In addition to stimulating adipocytes to uptake glucose, FGF21 also is involved in signaling in the hypothalamus to suppress sugar intake and alcohol consumption. [ref]

This recent study of 450,000 people found that in addition to an increase in carbohydrate intake, those with the genetic variant had a higher alcohol intake and lower fat and protein intake. This corresponded to a decrease in FGF21 levels in the participants with the variant.

Interestingly, this new study showed that this increase in carbs did not correspond to an increase in BMI, but it actually correlates to a decrease in fat mass. Additionally, no increase in risk of type-2 diabetes was found for this variant. With sugar and carbs being demonized by health gurus everywhere, this once again shows how one size really doesn’t always fit all when it comes to diet advice.

Check your 23andMe results for rs838133 (v4, v5):

  • AA: sweet preference, higher carb (lower protein and fat) intake [ref] [ref]
  • AG: somewhat more likely to prefer sweets, higher carbs
  • GG: normal

A couple of words of caution here: I wouldn’t take this as an ‘ok to eat a bunch of cookies’ gene if you are diabetic or prediabetic. Common sense still applies here. I would also like to point out that this genetic variant is linked to increased alcohol intake, so you may want to take a hard look at how much you are drinking if you have the genetic variant, especially if alcoholism runs in your family.

Author Information:   Debbie Moon
Debbie Moon is the founder of Genetic Lifehacks. She holds a Master of Science in Biological Sciences from Clemson University and an undergraduate degree in engineering. Debbie is a science communicator who is passionate about explaining evidence-based health information. Her goal with Genetic Lifehacks is to bridge the gap between the research hidden in scientific journals and everyone's ability to use that information. To contact Debbie, visit the contact page.