Weight and metabolism determined by genetics more than diet microbiologystudy

Shaped by fads and one-size-fits-all approaches, current dietary practices rely on the idea that everyone needs the same food to achieve similar results, an idea challenged by new research from the University of Virginia.

UVA medical researchers say genetic background has a more prominent impact on body weight, fat mass, blood sugars and lipids than specific diets. Researchers fed four different diets with similar macronutrient content to four genetically diverse groups of mice.

The diets were Mediterranean, vegetarian and vegan diets, in addition to the “typical American diet” commonly associated with negative health outcomes.

“People with weight issues often feel like they are eating the same thing as others who are close to them, but not getting the same results,” said Dr. Heather Ferris, associate professor of medicine and physician–scientist with a specialty in diabetes management. “It is likely individuals’ genetics is at play.”

“The research would not have been possible without close collaboration among several investigators with varied expertise,” said Dr. Susanna Keller, associate professor of medicine, whose research focuses on metabolic disease and cardiovascular complications.

Researchers found outcomes varied among mice with different genetic backgrounds within the same diet groups, suggesting that factors other than diet were at work. The results are published in the journal iScience.

“These conclusions may be used in precision medicine decision-making in the future,” said the paper’s first author, Jordan Reed, who graduated from UVA in 2023 with a doctorate in biomedical engineering. She worked with study leaders Keller, Mete Civelek, Sibylle Kranz, Ferris and Bijoy Kundu, all from UVA.

Scientists have explored the relationships between diet and metabolic effects, but there is insufficient research to prescribe diets based on personal genetics, researchers argue.

Currently, single nutrients like vitamin D are measured with supplement recommendations based on bringing blood levels to a point based on an average that is considered beneficial. “The recommendation is not based on your genetic background, only on an average blood level,” said Kranz, a UVA research dietitian and associate professor of kinesiology.

The team’s research and similar studies could lead to targeted research in humans with diverse genetic backgrounds. The goal is to design personalized dietary interventions to prevent or manage conditions like obesity or diabetes.

“We expect that at some time point in the future people will be able to go and see a health care provider and get tests to look at both their genes and nutrient levels,” Ferris, an associate professor of medicine, said.

“Commercial products that measure a couple of genes and recommend a diet for you are available,” Civelek, a UVA professor of genome sciences, said. “But these tests are not Food and Drug Administration-approved, do not take your current nutritional status into account and are backed by limited science at this stage.”

The team is hopeful that its research and other studies can begin to fill in the gaps of knowledge backed by science.