Fad of Matching Diet to DNA Ineffective, New Study Shows

individual genotype rarely correlates with suggested diets

By Jonny Lupsha, News Writer

Interaction between certain diets and individuals’ genotypes is minimal, according to new research. It was previously suggested that diets could be matched to specific DNA patterns. However, certain types of food do specifically affect our cells.

Close up of woman with salad on her plate
What we’ve always heard remains true: What we eat determines our level of nutrition and bodily function. Photo by bluedog studio / Shutterstock

A study published in the Journal of the American Medical Association on the JAMA Network™ website determined that the most effective diets can rarely, if ever, be determined by our DNA. “Some studies have reported that genotype variation could predispose individuals to differential weight loss that varies by diet type,” the study said. “However, the diet-genotype interaction for weight loss was not statistically significant. The finding of no significant difference in weight loss in genotype-matched vs. mismatched groups in the current study highlights the importance of conducting large, appropriately powered trials such as DIETFITS for validating early exploratory analyses.”

In other words, statistically speaking, matching a diet to your DNA rarely works and shouldn’t be considered a winning method for weight loss. The relationship between your unique body physiology and the foods you eat determine your level of nutrition: Certain types of foods affect our cells on a molecular level, regardless of our genetic make-up.

You Are What You Eat … Kind Of

“What you eat will ultimately make up portions of your cells, skin, hair, blood transportation systems, muscle, fat, and more,” said Dr. Michael Ormsbee, Associate Professor in the Department of Nutrition, Food, and Exercise Sciences and Assistant Director of the Institute of Sports Sciences and Medicine in the College of Human Sciences at Florida State University.

“The nutrients you eat are not just being transported around throughout our digestive systems and in the blood; they are also an ingrained part of every cell tissue that makes us who we are and what we do. Our bodies are, to a significant extent, composed of the foods that we eat.”

Dr. Ormsbee said that our cells bond together to make tissues, which make up our organs, which combine to make our entire bodies function properly. “If your cells are not healthy, they will not work properly; and if the cells don’t work properly, then the tissues won’t work properly; and if tissues aren’t working, then the systems begin to fail,” he said.

The best way to prevent this detrimental snowball effect is to keep our cells healthy by feeding them the right nutrients.

Using Unsaturated Fats to See the Bigger Picture

“The structures of your cells are made up of fats, proteins, carbohydrates, vitamins, and minerals,” Dr. Ormsbee said. “The foods we eat every single day are made up of fats, proteins, carbohydrates, vitamins, and minerals. The foods you eat have a major influence on your cellular function because they ultimately become your cells.”

If this idea seems a bit coincidental, there are several examples to shed light on the relationship between your diet and your cells. Dr. Ormsbee said that unsaturated fats are one such example. Cell membranes are semi-permeable, and this is due to the “fluid structure of the fats,” as he called it. Trans fats and saturated fats are more rigid than unsaturated fats.

“They don’t function the same way as the unsaturated fats, and they cause membranes to be much more rigid than is optimal, potentially limiting the functionality of the cells,” Dr. Ormsbee said. “Diets that are too high in one type of fat—for example, trans fats—might lead to a rigid, brittle cell membrane that cannot communicate as well as if they were comprised of a better mix of fat types.

“This is one reason why many nutritionists recommend eating all types of fats so that one type doesn’t predominate in the diet and end up altering the optimal functioning of those cells.”

So, even though our diets help determine who we are, that doesn’t mean that our genotypes should determine our diets.

Dr. Ormsbee is an Associate Professor in the Department of Nutrition, Food, and Exercise Sciences and Interim Director of the Institute of Sports Sciences and Medicine in the College of Human Sciences at Florida State University.

Dr. Michael Ormsbee contributed to this article. Dr. Ormsbee is an Associate Professor in the Department of Nutrition, Food, and Exercise Sciences and Assistant Director of the Institute of Sports Sciences and Medicine in the College of Human Sciences at Florida State University. He received his Ph.D. in Bioenergetics from East Carolina University.

About Jonny Lupsha, News Writer 391 Articles
Jonny is a freelance writer and novelist who lives in Sterling, Virginia. He has written for The Great Courses since 2017 and enjoys studying the courses as much as writing about them. Contact Jonny at lupshaj@teachco.com