Keto and Intermittent Fasting: The Dynamic Duo for Weight Loss and Optimal Health

Consider combining keto and intermittent fasting to burn fat and clear your mind?
Consider combining keto and intermittent fasting to burn fat and clear your mind?

The combination of the ketogenic diet plus an intermittent fasting lifestyle has recently skyrocketed in popularity. Intermittent fasting combined with the low-carb, high-fat keto diet is a bold and powerful trend for burning fat, losing weight, and sharpening mental clarity.

It’s not easy to start a fasting routine. Keto diets have their challenges. But once you get started, it gets easier and easier, especially when you break your fast with delicious ketogenic meals. By combining the keto diet with intermittent fasting, you can take advantage of both to reduce belly fat, which is key to achieving wellness and weight loss goals. Seeing results can also be a tremendous incentive to keep going.

This comprehensive guide to this dynamic diet duo explores the ins and outs of combining the keto diet and intermittent fasting, covering the benefits and risks of this dynamic duo. We’ll also examine the pros and cons of different fasting schedules and offer a simply delicious sample meal plan that’s guaranteed to tantalize your taste buds and melt that fat away.

How Does Keto Work?

The keto diet is a low-carb, high-fat, moderate-protein diet that puts your body into a state of ketosis. When you follow a traditional high-carb diet, your body relies primarily on glucose from carbohydrates for energy.

By reducing carbohydrate intake and replacing it with healthy fats, the body starts burning fat for fuel instead of glucose, effectively getting the benefits of a low-carb diet without feeling the carb restriction.

This metabolic switch to burning more body fat, known as ketosis, causes your liver to produce ketone bodies, which serve as an alternative energy source for your brain, muscles, and organs. Specifically, by doing keto along with fasting, you can maintain muscle mass while eating fewer calories, and usually without feeling the daily calorie restriction.

Woman breaking a fast with a keto meal.

The keto diet has been shown to help people lose weight, improve mental clarity, and manage various health conditions, such as type 2 diabetes and epilepsy. The macronutrient breakdown of the diet is typically 70–75% fat, 20–25% protein, and 5–10% carbohydrates.

By following a ketogenic diet plan, you can achieve and maintain ketosis, optimize your body’s fat-burning capabilities, and reap the health benefits of this low-carb lifestyle. That hard-to-achieve belly fat loss is within your reach.

How Does Intermittent Fasting Work?

Intermittent fasting involves strategically alternating periods of normal eating and fasting, with designated windows when you can and cannot eat. Rather than focusing on what foods to eat, the practice emphasizes when to eat them. This eat-fast alternation pushes the body to optimize its catalytic processes for weight loss and overall health. The idea is to concentrate eating into smaller windows of time, with longer periods of fasting in between. The goal is to give your body a break from constantly processing food and instead allow it to focus on repairing cells, boosting metabolism, and burning stored fat for fuel. 

This approach to eating has been practiced for centuries in a variety of religious, cultural, and health contexts. In recent years, intermittent fasting has gained popularity as a tool for weight loss and health optimization. Numerous scientific studies have validated its benefits for weight loss, blood sugar control, mental clarity, and overall well-being. By promoting the metabolic switch from using carbohydrate-derived glucose to burning long-dormant fat stores for energy, intermittent fasting boosts the body’s ability to shed excess weight and improve various aspects of health.

Can You Combine Keto and Intermittent Fasting? 

Yes, you can practice intermittent fasting with keto, and it’s a powerful metabolic combination. Combining the keto diet and intermittent fasting can create a synergistic effect, enhancing the benefits of both practices while minimizing the potential risks. Still, with great power comes great responsibility. Let’s look closer at the benefits and risks of merging these two dietary practices.

Benefits of Combining Keto and Intermittent Fasting

When you adopt the keto diet, you prime your body to burn fat for fuel, thanks to its low-carb, high-fat regimen. Add intermittent fasting into the mix, and you further boost your metabolism’s ability to tap into fat stores and exploit them for energy. 

You can expect the following benefits from an intermittent fasting keto diet:

#1 Accelerated weight loss

Both the keto diet and intermittent fasting promote the burning of body fat, and combining them can lead to a faster keto weight loss timeline. When your body is in ketosis, and you start fasting, your body is induced to burn stored fat for energy more efficiently.

#2 Improved blood sugar control

Low-carb intermittent fasting has been shown to help stabilize blood sugar levels, improve insulin levels, and reduce glycogen stores. This can be particularly important for people with type 2 diabetes or prediabetes.

#3 Enhanced clarity

Ketones are a super-efficient fuel source for the brain, and fasting has been linked to the production of BDNF, which supports cognitive function. This combination may help improve focus, memory, and overall brain health.

# 4 Increased autophagy

This cellular process, which literally means “self-eating,” helps clear out damaged cells and regenerate new, healthy ones. Both ketosis and fasting can stimulate autophagy, which may contribute to improved overall health and reduced risk of chronic diseases.

#5 Simplified meal planning

When practicing intermittent fasting, you have fewer meals to plan. This can make meal preparation and grocery shopping more manageable. It’s particularly helpful when following ketogenic diets, which require careful planning and tracking of macronutrients.

Woman opened the fridge checking what to eat.

Risks of Combining Keto and Intermittent Fasting

While combining the keto diet with intermittent fasting can yield impressive results, be aware of the risks of this change in eating habits and monitor your body’s response carefully. Make sure you are getting enough nutrients and calories during your condensed eating window, and be aware of any signs of fatigue or hormonal imbalances. It’s always a good idea to consult a health or nutrition professional before starting any new diet, especially one as powerful as this one.

You should keep an eye on the following:

#1 Nutrient deficiencies

Both keto and fasting can lead to reduced nutrients if you’re not consuming a balanced diet. Ensure you eat nutrient-dense foods and consider taking supplements if needed.

#2 Overeating or undereating

Some individuals may find it challenging to consume enough calories in their eating window, while others might overeat due to hunger. Listen to your body and eat mindfully.

#3 Hormonal imbalances

Fasting can impact hormone levels, particularly in women. If you experience irregular menstrual cycles, mood swings, or other hormonal issues, consult with a healthcare professional or nutritional specialist whom you trust.

#4 Decreased athletic performance

Intense exercise may be more difficult during fasting, especially at the beginning. Consider adjusting your keto exercise plan to accommodate your energy level and take it a little easier at first.

#5 Proceed with care

Keto and intermittent fasting may not be appropriate for pregnant or breastfeeding women, individuals with a history of eating disorders, or some medical conditions. Consult a healthcare professional before starting any new diet.

Different Types of Fasting Windows

There are various fasting schedules you can choose from when practicing intermittent fasting on the keto diet. Some of the most popular methods include:

16:8 method

Fast for 16 hours and eat during an 8-hour window. This approach is also called time-restricted eating.

18:6 method

Fast for 18 hours and eat during a 6-hour window, providing a longer fasting period and shorter eating window.

20:4 method

Fast for 20 hours and eat during a 4-hour window, also known as the Warrior Diet.

5:2 method

Eat normally for 5 days a week and restrict intake of calories to about 500–600 calories on the other 2 non-consecutive days.

Alternate-day fasting

Eat normally on one day and fast or restrict calories on the next day, repeating this pattern throughout the week.

Eat Stop Eat

Fast for 24 hours once or twice a week.

Some of these, you will find, are more difficult than others. Choose a fasting regimen and eating windows that you can maintain over time. Consider your lifestyle, goals, personal preferences, and body composition. Alternate-day fasting, in particular, can be challenging. Always proceed with caution, especially if you have health conditions such as heart disease or diabetes. Before starting any diet, consult with a trusted professional who is knowledgeable about clinical nutrition.

Which Fasting Hours Are Best for Keto? 

Choosing the fasting times that work best for you on the keto diet is a personal decision. It depends on your lifestyle, goals, habits, and preferences. While there’s no one-size-fits-all answer, two popular intermittent fasting methods work particularly well with keto.

The 16:8 method is the most common choice for people following keto. This approach of a 16-hour fast with an 8-hour eating window can maintain ketogenic fat burning without causing extreme hunger or fatigue. If you’re new to fasting, you can even start with a shorter fasting window, such as 14 hours, and gradually increase it as your body adapts.

Want more flexibility? The 5:2 approach is another great option. Eat a typical keto diet 5 days a week and restrict calories the other 2 days. This promotes ketosis and weight loss while allowing for relaxed eating on non-fasting days. Whichever option you choose, listen to your body and adjust accordingly.

How to Start Fasting on Keto? 

To begin combining keto and intermittent fasting, follow these steps:

#1 Start with the standard ketogenic diet

Adapt to a low-carb, high-fat diet first to ease the transition into fasting. This will help your body become fat-adapted and more efficient at using fat for fuel.

#2 Choose a fasting method

Select an intermittent fasting schedule that fits your lifestyle, goals, and preferences. Consider starting with a shorter fasting window, such as the 16:8 method, and adjust as needed.

#3 Monitor your energy levels and hunger

As you start fasting, pay attention to how your body feels. If you experience extreme hunger, fatigue, or irritability, consider adjusting your fasting schedule or eating window.

#4 Eat nutrient-dense foods

When breaking your fast, prioritize high-quality foods that are dense in nutrients, such as leafy greens, healthy dietary fats, and lean proteins.

#5 Gradually increase your fasting window

Start with shorter fasting periods and slowly work your way up to longer durations as your body adjusts.

#6 Adjust your exercise routine at first

If needed, modify your workout schedule to accommodate your energy levels during fasting periods.

#7 Stay hydrated throughout the day

Drinking plenty of water is essential during fasting periods to prevent dehydration and support overall health.

#8 Prioritize your electrolytes

When fasting with keto, it’s crucial to maintain proper electrolyte balance by increasing food intake that is rich in potassium, magnesium, and sodium or taking supplements.

#9 Listen to your body

Pay attention to your body’s signals and adjust your fasting schedule or duration as needed. If you experience extreme fatigue or other adverse effects, consider shortening your fasting periods or consulting a healthcare professional.

#10 Break fasts only with keto-friendly meals

Perhaps needless to say: when it’s time to eat, only eat nutrient-dense, low-carb foods to maintain ketosis and support your health goals. Also, pay attention to how much sugar you eat on the ketogenic diet as it can be present in many seemingly low-carb foods.  

#11 Use the Keto Cycle app daily

The Keto Cycle app offers a clear, comprehensive guide for your keto diet and meals, as well as connecting you to fellow keto dieters, some of whom are enthusiastic intermittent fasters. For anyone looking to combine the two practices, or keto dieting generally, the app offers personalized meal plans, intermittent fasting schedules, and ongoing support to help you navigate the process and achieve your health goals.

keto quiz

Sample Keto Intermittent Fasting Meal Plan

Here’s a 3-day meal plan combining keto and intermittent fasting using the 16:8 method:

Day 1:

Day 2:

Day 3:

Intermittent Fasting Benefits

Weight loss and fat dissolution

Studies have shown that intermittent fasting can help individuals lose weight and burn fat by reducing the amount of calories they eat and boosting their metabolism. When combined with a low-carb diet, the fat-burning potential may be even greater due to enhanced ketone production.

You can dip below your weight loss plateau and improve body composition by reducing carb intake, skipping breakfast, and still eating the delicious high-protein and fatty foods you crave. 

Woman checking her weight loss results on keto.

One interesting study examines whether time-based fasting or calorie restriction is better for losing weight and diabetic health. Preliminary findings show promise for intermittent and alternate-day fasting as superior alternatives to calorie reduction for weight loss and type 2 diabetes risk reduction in overweight and obese populations.

Improved insulin sensitivity

Intermittent fasting has been shown to improve insulin sensitivity and reduce oxidative stress in men with prediabetes. The practice is believed to benefit people with type 2 diabetes or those at risk of developing the condition.

Mitigation of bacterial infections

Studies have shown that fasting can mitigate sickness, slowing the spread and impact of bacterial infections.

Enhanced mental clarity

Fasting has been linked to various brain health benefits, including reduced inflammation, increased production of brain-derived neurotrophic factor (BDNF), and improved cognitive function. For those concerned with dementia and Alzheimer’s disease, these are significant indicators.

Cellular repair and longevity

Intermittent fasting, studies show, stimulates a cellular repair process called autophagy. This helps eliminate damaged cells and promotes the growth of new, healthy cells. This process has been linked to increased longevity and a reduced risk of chronic diseases.

Conclusion: Take Your Fast and Make It Last!

The combination of the ketogenic diet and intermittent fasting offers numerous benefits, most notably accelerated weight loss, improved blood sugar control, and enhanced mental clarity. The biggest impact may be on your stomach and body shape, as the combined effect of a more efficient metabolism and ketosis burns fat stores and releases energy more efficiently. 

Intermittent fasting results will vary, of course, and you should listen to your body and respond accordingly. Take it easy at first, and consider shorter fasting windows as your body adjusts.

By choosing a fasting schedule that works best for you and ensuring that you consume foods dense in nutrients and low in carbs, you can merge keto and intermittent fasting safely for an unmatched fat-burning, health-boosting, and mind-clearing dietary strategy.

keto quiz


Category: Keto 101