Answer – Yes, you can do intermittent fasting while on the keto diet. However, you’ll want to keep a few things in mind while combining keto and IF:
First, people can mean very different things when they use the term “intermittent fasting.”
For some, intermittent fasting means confining their day’s meals to a specific time window, such as 8 hours each day (known as 16:8 because of a 16-hour fast and an 8-hour feeding window). This style of IF is also known as Time Restricted Feeding. Others practice an every-other-day approach to intermittent fasting, in which the practitioner alternates days between eating normally and fasting.There’s even a fairly-common IF variation that involves eating all the day’s calories within a single meal, which is sometimes shortened to the acronym OMAD (for One Meal A Day).What all these intermittent fasting variations have in common (and there are many others) is that they all include some period of calorie reduction or total elimination.
Fasting may help “kick start” ketosis.
The goal of following the ketogenic diet is to get into a state of ketosis. The short explanation of ketosis is when the body utilizes ketones bodies for fuel instead of glucose, which is the more common source of energy for those following a typical, modern diet.This is accomplished by restricting carbohydrate intake for a period of time, which “forces” the body to switch over to ketosis in order to meet its energy needs.The follower of intermittent fasting is also restricting their carbohydrate intake, which can then (depending on the length of fast) start the production and utilization of ketones.(Whether this happens, and to what extent, will depend on several things, such as the length of the fast and the individual’s unique biology. Some folks get into ketosis easier and quicker than others.) Because of this, many have found that starting their keto diet with a brief fast makes the transition into ketosis easier. And, starting keto with a fast may also lessen the effects of the keto flu for some (for more about the keto flu click here).
Keto and intermittent fasting should be compatible over the long term.
Aside from using IF to jump start ketosis when first starting on keto, intermittent fasting and the ketogenic diet can usually be successfully combined over the long term.The main requirement of keto is restricting carbohydrate consumption in order to maintain ketosis. As long as the intermittent fasting follows the macro-nutrient requirements of keto (typically less than 5% carbs, 75% fats and the balance of calories from protein) there should be no reason why a healthy individual can’t combine a ketogenic diet while practicing intermittent fasting.