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The keto diet, or ketogenic diet, requires eating high-fat, low-carbohydrate foods such as bacon. Starving the body of carbohydrates makes it burn fat, but research suggests the body reacts by building up stores of fat again. Photo: Shutterstock

Keto diet only works for a week before problem that can cause obesity and diabetes appears, study on mice shows

  • Research from Yale University suggests benefits of eating a high-fat, low-carb diet may be time-limited
  • After a week on the diet, the body starts replenishing its stores of fat faster than they can be burned, the study indicates. A follow-up human study is needed

If the start of the new year led you to go on the ketogenic diet in an effort to lose weight, a new study suggests you may have been on it a little too long.

Researchers at Yale University in the United States have conducted a study on mice to review the effects of the keto diet. They discovered that beyond a week, the benefits begin to cease.

The study was recently published in Nature Metabolism and results indicate that over a limited time period, consuming a high-fat, low-carb diet can possibly offer health benefits to humans, Yale News reports. They include lowering the risk of diabetes and inflammation.

The diet’s positive effects are related to cells called gamma delta T-cells, immune cells that protect the tissue and lower the risk of diabetes and inflammation. However, the same cells are also tied to negative effects of the keto diet.
A selection of food that can be eaten on the high-fat, low-carb Keto diet. Photo: Shutterstock

Vishwa Deep Dixit, lead author of the study, who is a professor of comparative medicine and immunology at the Yale School of Medicine, says the keto diet tricks the body into burning fat. The body acts as if it’s in starvation mode when the low consumption of carbohydrates causes glucose levels to drop.

Despite the body not actually being in starvation mode, it begins burning fat instead of carbohydrates. That leads to the release of ketone bodies, which are an alternative source of fuel. As ketone bodies burn in the body, gamma delta T-cells expand throughout.

Vishwa Deep Dixit is a professor of comparative medicine and immunology at the Yale School of Medicine and lead author of the study. Photo: Yale University
Dixit says this process improves metabolism and reduces diabetes risk and inflammation. He says mice showed decreased blood sugar levels and inflammation after a week on a keto diet.

However, when the body acts as if it’s in starvation mode, researchers found fat gets stored in the body at the same time that fat breakdown occurs. As mice continue the high-fat diet, Dixit says they start to store more fat than they can burn, and obesity and diabetes begins to develop. “They lose the protective gamma delta T-cells in the fat,” Dixit says.

Keto for beginners: how it works, what you can and cannot eat

“Our findings highlight the interplay between metabolism and the immune system, and how it coordinates maintenance of healthy tissue function,” says comparative medicine postdoctoral fellow Emily Goldberg, who discovered that the keto diet expands gamma-delta T cells in mice.

Despite the findings of the mice trial, however, Dixit says long-term human clinical trials are needed.

“Before such a diet can be prescribed, a large clinical trial in controlled conditions is necessary to understand the mechanism behind metabolic and immunological benefits or any potential harm to individuals who are overweight and pre-diabetic,” Dixit says.

The Mayo Clinic Diet by Donald D. Hensrud.
Dr Donald Hensrud of the Mayo Clinic. Photo: Mayo Clinic

The results come after Dr Donald Hensrud of the Mayo Clinic voiced opposition to the diet. Hensrud, author of The Mayo Clinic Diet Book, says the keto diet is not the magic formula people believe it is.

“People want to believe,” he says. “They want an easy way out. They want the magic panacea.”