Keto Diet – Short Term Only
New research from Yale University found that the fashionable ketogenic diet can improve health and aid weight loss in the short term but the negative effects of the diet start to arise after about a week in mice. The mice who were fed a keto diet for more than 7 days consumed more fat than they could burn and had an increased risk of developing diabetes and obesity (1).
What is a Ketogenic Diet?
The keto diet is a very high fat diet with some protein and a very small amount of carbohydrate. It has been popularised by celebrities who claim to have lost weight on the diet, and by many websites heralding the benefits of going low carb and high fat.
The very low carbohydrate content of the diet means the body’s blood glucose levels drop very low which puts the body into a starvation state, although it is not actually starving as food is being eaten. This triggers the body to burn fat stores instead of burning glucose. The fat burning leads to ketone bodies being produced. Ketone bodies are alternative sources of fuel. They allow humans to survive periods of starvation or prolonged exercise when glucose from carbohydrates is scarce. This is called being in ketosis.
What are the effects of Ketosis?
In the short term being in ketosis leads to a reduction in inflammation and improved metabolism. However, the researchers found that when the body is in the mode of starving but not starving it is actually storing fat at the same time as breaking down fat for energy. If the mice in the study continued to eat the high fat, low carb diet beyond 7 days they didn’t burn as much fat as they took in, leading to weight gain, impaired metabolic health and type 2 diabetes.
What does this mean for health?
In lots of ways this is good news as no one really wants to be on a restrictive diet, such as the keto diet, forever. It is not yet clear what the ideal length of time to be on the diet for humans would be. However, it may be that following the keto diet for a week before embarking on a long term healthy eating plan could be a possible way forward for people with certain health or weight problems. That said, there are many other tried and tested safe ways of losing weight and gaining health. Read the blog posts Weight Loss Strategies that Last and Breakfast Like a King for simple strategies that lead to long term weight loss
It is important to consult with your medical specialist before embarking on any restrictive diet.
1. Goldberg EL, et al. Ketogenesis activates metabolically protective γδ T cells in visceral adipose tissue. Nature Metabol. 2020; 2 (1): 50