Can You Do Keto While Intermittent Fasting?

Combining a keto diet with an intermittent fasting protocol can be done, but it may not be a good idea, especially if you're new to both diet methods. However, if done safely, it may be even more efficient than simply sticking with the keto diet. Here's why it works, and how to do both the keto diet and intermittent fasting the right way.

"Practicing IF [intermittent fasting] while on the keto diet may help the body reach ketosis faster," registered dietitian Danielle Schaub told Women's Health. She explains this is because both diets make the body burn fat as fuel more efficiently.

The keto diet — cutting out nearly all carbohydrates — is already restrictive, and can be difficult to adapt to and difficult to maintain. It can be tough to find the balance between eating enough while keeping carbohydrate intake low. Like most diets, it works for some people, while others struggle with it (via the University of Chicago).

An intermittent fasting plan, whether it involves eating during a certain time window of the day or alternating higher and lower caloric intake throughout the week, is meant to help speed up weight loss and improve other health outcomes like blood sugar control and inflammation (via Healthline). Like the keto diet, some people find it easy to adhere to while others struggle with the restrictive nature.

Is intermittent fasting while on a keto diet healthy?

When combined, the resulting diet can feel very restrictive — similar to combining a vegetarian or vegan diet with the keto diet — but it's possible it can be done safely. The key is to ease into this style of eating. Start with one diet or the other: First, get used to how eating a keto diet feels (and get through the 'keto flu' phase), or begin by adjusting to whatever style of intermittent fasting feels right for you. Then, slowly begin to ease into the other diet, again, taking a slow approach. For example, if you've adapted to the keto diet, start intermittent fasting by restricting your hours of eating to 12 (from 7 a.m. to 7 p.m., for example) and get used to that before cutting back to eating for only 10 hours during the day, then down to eight hours of eating time daily, registered dietitian Aja Gyimah told Women's Health.

The biggest downfall of this diet is that it may be hard to stick to, since there are so many rules to follow. But if your goal is dropping a few pounds, experts generally agree that a combination of intermittent fasting and the keto diet can speed up ketosis and can lead to weight loss (via Everyday Health).

It's important to remember that this style of eating isn't for everyone. Pregnant or nursing women, children, people with histories of disordered eating, and those with pre-existing health conditions should talk to a doctor before starting any restrictive diet.