The ketogenic diet, or keto diet, is a popular weight-loss approach. It works by drastically reducing the amount of carbohydrates to just 1 percent of one's daily calories, with the remaining 99 percent coming from fats and proteins (although variations of the diet do exist). A new study on mice suggests that a short period on the keto diet is beneficial, lowering the risk of diabetes and inflammation, but in the long run, negative effects are dominant.

The main source of fuel for cells in humans and mice alike is glucose. This is a simple sugar derived from the many forms of carbohydrates that we eat. The keto approach tricks the body into thinking it is starving, burning fats and using ketone bodies as an alternative source of cell fuel. At the same time, the body begins to produce special antibodies called gamma delta T-cells to protect tissues.

As reported in Nature Metabolism, the researchers observed that mice put on this keto diet had lower blood sugar levels and inflammation for the first week, as well as burned fat. But after the first week, the fat-loss effect was compensated by natural fat storage. Also of concern was the loss of the protective gamma delta T-cells.

"They lose the protective gamma delta T-cells in the fat," said senior author Vishwa Deep Dixit, from the Yale School of Medicine, in a statement.

“Our findings highlight the interplay between metabolism and the immune system, and how it coordinates maintenance of healthy tissue function,” added lead author Dr Emily Goldberg, also from the Yale School of Medicine.

The team states that more research is necessary to understand how the keto diet translates to humans. Some people may find benefits in it, but it is too early to say if the diet can be employed to manage certain conditions.

“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.

The finding that the diet is best performed in short bursts is probably an appealing one for many. In fact, Dixit added: “Who wants to be on a diet forever?”