The keto diet is a high-fat, very low-carb diet. Meals are 70–80% fat and around 5-10% carbs.
Usually, your body breaks carbohydrates down into glucose in your body, which provides energy.
If you don’t eat many carbs, your body switches to burning ketones, which are made from fat. This is called ketosis.
Because the keto diet forces your body to burn fat rather than glucose, it can help you lose weight. However, because it’s a tough diet to stick to, the weight may not stay off for long.
Importantly, there’s little information on the long-term effects of following the keto diet — partly because it's difficult to maintain.