A new study, published last week in the journal Nature Metabolism, has found that a ketogenic (keto) diet offers positive benefits for a limited period of time and negative effects after about a week.
Researchers from the Yale School of Medicine conducted the study on mice and found that the keto diet could improve human health by reducing the risk of diabetes and inflammation for a shorter period of time.
The researchers found that both positive and negative effects of the keto diet are related to the immune cells known as “gamma delta T-cells,” which protect bodily tissues and lower the risk of inflammation and diabetes.
The keto diet provides 99 percent of calories from protein and fat and only 1 percent from carbs.
Lead study author Vishwa Deep Dixit from the Yale School of Medicine said, “A keto diet tricks the body into burning fat.”
“When the body’s glucose level is reduced due to the diet’s low carbohydrate content, the body acts as if it is in a starvation state—although it is not—and begins burning fats instead of carbohydrates,” he added. This process in turn yields chemicals called ketone bodies as an alternative source of fuel. When the body burns ketone bodies, tissue-protective gamma delta T-cells expand throughout the body.”
Dixit continued, “This reduces diabetes risk and inflammation, and improves the body’s metabolism. After a week on the keto diet, he said, mice show a reduction in blood sugar levels and inflammation.”
The researchers, however, found that fat storage and fat breakdown happen simultaneously when the body is in the “starving-not-starving” mode. They found that mice consumed more fat than they can burn when they continue to eat the high-fat and low-carb diet for more than a week, increasing their risk of obesity and diabetes.
Dixit explained, “They lose the protective gamma delta T-cells in the fat.”
The researchers said long-term human trials are still needed to understand the health benefits of the keto diet.
“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,” said Dixit.
He explained, “Obesity and type 2 diabetes are lifestyle diseases. Diet allows people a way to be in control.”
The latest findings have helped the researchers to better understand the mechanism of the keto diet and why it offers health benefits for a limited period of time.
Emily Goldberg, who discovered that the keto diet expands gamma-delta T cells in mice, said, “Our findings highlight the interplay between metabolism and the immune system, and how it coordinates maintenance of healthy tissue function.”
Considering the findings, Dixit explained the keto diet is better in small doses, which is good news. “Who wants to be on a diet forever?” he added.
