Intermittent Fasting and Keto: Should You Combine the Two? (2024)

The keto diet and intermittent fasting are two of the hottest current health trends.

Many health-conscious people use these methods to drop weight and control certain health conditions.

While both have solid research backing their purported benefits, many people wonder if it’s safe and effective to combine the two.

This article defines intermittent fasting and the keto diet and explains whether combining the two is a good idea.

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Intermittent fasting is an eating method that cycles between calorie restriction — or fasting — and normal food consumption during a specific time period (1).

There are many different types of intermittent fasting routines, including the 5:2 method, the Warrior Diet and alternate-day fasting.

Perhaps the most popular kind of intermittent fasting is the 16/8 method, which involves eating during an eight-hour timeframe before fasting for 16.

Intermittent fasting is mainly used as a weight loss technique.

However, studies found that it may benefit health in many other ways.

For example, intermittent fasting has been shown to reduce inflammation and improve brain function and blood sugar control (2, 3, 4).

Summary

Intermittent fasting is an eating pattern that involves rotating between periods of fasting and normal eating. Popular methods include the 5:2 and 16/8 methods.

The ketogenic (keto) diet is a high-fat, very low-carb way of eating.

Carbs are typically reduced to 20 to 50 grams per day, which forces your body to rely on fats instead of glucose for its main energy source (5).

In the metabolic process known as ketosis, your body breaks down fats to form substances called ketones that serve as an alternate fuel source (6).

This diet is an effective way to shed pounds, but it has several other benefits as well.

The keto diet has been used for nearly a century to treat epilepsy and also demonstrates promise for other neurological disorders (7).

For instance, the keto diet may improve mental symptoms in people with Alzheimer’s disease (8).

What’s more, it may reduce blood sugar, improve insulin resistance and lower heart disease risk factors like triglyceride levels (9, 10).

Summary

The ketogenic diet is a very low-carb, high-fat diet linked to potential health benefits, such as weight loss and improved blood sugar control.

If you commit to the ketogenic diet while doing intermittent fasting as well, it could offer the following benefits.

May smooth your path to ketosis

Intermittent fasting may help your body reach ketosis quicker than the keto diet alone.

That’s because your body, when fasting, maintains its energy balance by shifting its fuel source from carbs to fats — the exact premise of the keto diet (11).

During fasting, insulin levels and glycogen stores decrease, leading your body to naturally start burning fat for fuel (12).

For anyone who struggles to reach ketosis while on a keto diet, adding intermittent fasting may effectively jumpstart your process.

May lead to more fat loss

Combining the diet and the fast may help you burn more fat than the diet alone.

Because intermittent fasting boosts metabolism by promoting thermogenesis, or heat production, your body may start utilizing stubborn fat stores (13).

Several studies reveal that intermittent fasting can powerfully and safely drop excess body fat.

In an eight-week study in 34 resistance-trained men, those who practiced the 16/8 method of intermittent fasting lost nearly 14% more body fat than those following a normal eating pattern (14).

Similarly, a review of 28 studies noted that people who used intermittent fasting lost an average of 7.3 pounds (3.3 kg) more fat mass than those following very low-calorie diets (15).

Plus, intermittent fasting may preserve muscle mass during weight loss and improve energy levels, which may be helpful for keto dieters looking to improve athletic performance and drop body fat (16, 17).

Additionally, studies underscore that intermittent fasting can reduce hunger and promote feelings of fullness, which may aid weight loss (18).

Summary

Combining intermittent fasting with a keto diet may help you reach ketosis faster and drop more body fat than a keto diet alone.

Combining the ketogenic diet with intermittent fasting is likely safe for most people.

However, pregnant or breastfeeding women and those with a history of disordered eating should avoid intermittent fasting.

People with certain health conditions, such as diabetes or heart disease, should consult with a doctor before trying intermittent fasting on the keto diet.

Though some people may find merging the practices helpful, it’s important to note that it may not work for everyone.

Some people may find that fasting on the keto diet is too difficult, or they may experience adverse reactions, such as overeating on non-fasting days, irritability and fatigue (19).

Keep in mind that intermittent fasting is not necessary to reach ketosis, even though it can be used as a tool to do so quickly.

Simply following a healthy, well-rounded keto diet is enough for anyone looking to improve health by cutting down on carbs.

Summary

Though simultaneous intermittent fasting and ketogenic dieting may enhance each other’s effectiveness, it’s unnecessary to combine both. Depending on your health goals, you may choose one over the other.

Combining the keto diet with intermittent fasting may help you reach ketosis faster than a keto diet alone. It may also result in greater fat loss.

However, while this method may work wonders for some, it’s not necessary to mix both, and some people should avoid this combination.

You’re welcome to experiment and see whether a combination — or one practice on its own — works best for you. But as with any major lifestyle change, it’s advisable to speak to your healthcare provider first.