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How Long Should I Stay On The Keto Diet and Can I Eat Carbs Again?

In this series, we defined the Keto diet as a low-carbohydrate, high fat, and adequate protein diet. We discussed how this method of eating puts you into a persistent state of ketolysis, using breakdown products of your consumed and stored fat as energy.

So how long can you stay on such a diet, and can you ever eat carbohydrates on this diet?

I’ll answer the second question first. Your body will enter a state of ketolysis with an approximate daily carbohydrate intake of 50 g or less. If you can achieve this, less than 20 g per day will be more likely to place you in this state quickly (within 3 days of starting the diet) and stay there. Once you start consuming more carbohydrates, your body will leave the state of ketolysis, your insulin levels will rise in response, and your body will once again use carbs as energy, storing what you don’t use in your muscles, liver, and as fat. In other words, consuming more carbs takes you out of this diet, but as long as you have met your goals, nothing is wrong with that as long as you maintain a balanced diet with healthy choices.

For the first question – how long can you stay on the Keto diet – it depends. If you have reached a point of being underweight (you can check a body mass index table for this), you should not be on a diet that limits your total caloric intake or your macronutrients (carbs, fats, or proteins). If you are overweight, or are within a normal range but are seeking to shed fat and gain lean muscle, you can stay on this diet indefinitely. A common question is whether or not the high fat content will raise your triglyceride and cholesterol levels, and increases your risk of cardiovascular disease. While you should always check with your doctor first, the Keto diet, in general, does not do this by itself. There may be other factors, however, such as genetics that lead to these risks. The fact is, as long as you are consuming at, or less, than your body’s total daily energy expenditure – something you can calculate with most fitness apps today – your body will use fat instead of keeping in your body. That means your overall level of fats in your blood and storage will be lower, and it will instead be used for energy and your body’s essential functions! Therefore, you can theoretically follow the Keto diet indefinitely.

Diets, and diet fads, come and go. Some concepts, though, are rooted in basic biochemistry and physiology. I have done this series on the Keto diet because, on the surface, it may not seem intuitive. I hope that my explanations have helped you become a more informed in your dietary choices.

Published on Jun 11, 2019 by Dr. Shawn Tsuda, FACS

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