Why You Should Avoid Carb Cycling on Keto

Carb cycling is a popular dietary pattern, particularly among athletes, that alternates between high-carb days and low-carb days.

Eating more carbs on certain days is also a strategy often used by individuals new to a high-fat ketogenic diet to feel less restricted and boost energy. However, carb cycling is unsustainable on keto and may slow down your health and fitness success. 

Discover the truth behind carb cycling on keto and learn how to get back on track after a carb-laden cheat day quickly.

What is carb cycling?

Carb cycling is a dieting strategy commonly used by endurance athletes and bodybuilders. 

This approach intends to reach fitness goals and optimize physique by alternating between low-carb and high-carb days, widely known as carb loading.

Dietary carbohydrates are converted into blood sugar, which serves as the body's primary fuel source. Blood sugar that isn’t immediately used is stored as glycogen in reserves located in the liver and skeletal muscles. 

On low-carb days, blood sugar and glycogen stores are depleted. This pushes the body into ketosis, a metabolic state characterized by utilizing fat to generate energy instead of using sugar as a fuel source.

On high-carb days, blood sugar levels rise, and glycogen stores are replenished, which stops ketosis and fat-burning. It’s widely believed that this is beneficial for building muscle and providing sustainable energy. 

In addition, carb loading has become more common in individuals following a low-carb diet such as keto, a practice also known as cyclical keto.

Cyclical keto involves eating a strict ketogenic diet for several days, followed by 1 to 3 days of consuming a high-carbohydrate diet. This method is used to induce fat-burning without feeling deprived of high-carb foods.

For example, some keto dieters limit carbohydrate intake to between 20 and 50 grams of net carbs five days a week and consume more than 50 grams on the weekend. 

However, carb loading on keto won’t support muscle growth or enhance performance and likely will slow down weight loss, trigger persistent cravings, and contribute to metabolic imbalances.

Watch the video below to learn more about why you shouldn’t do carb cycling on keto.

Are carbohydrates essential for health?

Many entities list carbohydrates as essential nutrients, including the United States Department of Agriculture (USDA) and Health and Human Services (HHS), which help set the Dietary Guidelines for Americans (DGA).

The three main types of carbohydrates include sugars, starches, and fiber, and the DGA recommend that carbohydrates should comprise between 45 and 65 percent of your daily calorie intake. 

Fiber, abundant in plant foods such as vegetables, is essential for human health. It serves as the primary fuel source for beneficial gut bacteria, aiding digestion, nutrient absorption, and immune functions. 

Sugars and starches, such as potatoes, cane sugar, and refined grains, provide little nutritional value compared to non-starchy vegetables, which are rich sources of vitamins, minerals, and fiber. 

Contrary to common belief, carbohydrates aren’t the only source of energy. Blood sugar can be produced through a metabolic process known as gluconeogenesis, in which the liver synthesizes glucose from amino acids and certain fats. 

In addition, obtaining the majority of calories from healthy fats provides ample energy. This explains why low-carb diets offer sustainable energy and maintain normal brain function without having to rely on carbohydrates. 

Why you should avoid carb cycling 

The primary downside of combining keto with a carb cycling schedule is that your body won’t remain in ketosis. This can negate the many health benefits of a low-carb diet, such as improved insulin resistance, increased energy, mental clarity, and lower inflammation.

Depending on your metabolic flexibility, it can take between 1 to 3 days to re-enter ketosis after one day of carb cycling. 

Additionally, entering ketosis can take longer for individuals new to keto and those who have never been fully keto-adapted.

If you follow a strict keto plan on the weekdays but eat processed foods and carb-heavy meals on weekends, you’ll likely only be in ketosis two to three days each week. 

Frequent shifts in and out of ketosis can disrupt the body's ability to efficiently burn fat for fuel, potentially leading to weight gain or a plateau in weight loss progress.

In addition, carbohydrates cause blood sugar fluctuations, a major trigger for cravings and hunger. This can make it difficult to sustain a high-fat diet and may lead to inconsistent results.

What to do instead of carb cycling

If you’re thinking of starting a carb cycling plan to boost energy, gain muscle, or lose weight faster, there are more effective dietary patterns to consider. 

On a carb-cycling diet, the rise in blood sugar levels may increase energy levels temporarily. However, you’ll likely experience fatigue and carb cravings once blood sugar levels decrease.

In contrast, during ketosis, blood sugar levels remain steady, and the body relies on fat as a primary fuel source, which offers consistent and reliable energy throughout the day.

A study published in the Journal of Strength and Conditioning Research concluded, “The ketogenic diet can be used in combination with resistance training to cause favorable changes in body composition, performance, and hormonal profiles in resistance-trained men.”

The researchers also found that keto was more effective at creating lean body mass than a traditional Western diet. 

In addition, intermittent fasting (IF), which involves alternating between periods of eating and fasting, maximizes the fat-burning benefits of ketosis and helps prevent blood sugar fluctuations and weight gain. 

Intermittent fasting routines can also optimize athletic performance by increasing human growth hormone (HGH) production, which helps muscle formation and prevents muscle loss. 

If you’re considering carb cycling on keto because you hit a weight loss plateau, you may benefit from reviewing your fat intake.

Although ketosis pushes the body to burn fat, the liver prioritizes dietary fats over stored body fats. Reducing fat consumption, such as limiting or avoiding fat bombs and bulletproof coffee and consuming more vegetables, can help enhance your body’s ability to tap into body fat.

Adding IF to your keto diet plan can also enhance metabolic health by increasing insulin sensitivity, which is linked to a healthy body weight and lower risk of diabetes.  

Is it ever okay to have a cheat day on keto?

Many keto dieters are tempted to have a carb-heavy cheat day. But deviating from keto can make it more difficult to get back on track, especially for beginners who may not be fully fat-adapted. 

“I don’t recommend that you cheat when you’re first starting keto,” explains Dr. Berg. “It could take 20 hours or longer to get back into ketosis after just one carb-rich meal.”

The real goal of a nutritious low-carb diet such as Healthy Keto® and IF is to build up your health and enhance metabolic flexibility so that one cheat day won’t be as damaging.

Though deviating from a Healthy Keto plan isn’t recommended, taking a cheat day can be a great way to monitor how your body feels on a ketogenic diet compared to higher carb intake. This can be insightful and help encourage you to avoid cheat days.

If you’re going to cheat on keto, it’s best to stick to whole foods, such as fruit, fiber-rich carbs, or raw honey, rather than refined and ultra-processed foods, which have little to no nutritional value. 

Tips for recovering from a keto cheat day

Though deviating from the ketogenic diet plan will likely kick you out of ketosis, there are a few things you can do to recover from a cheat day quickly. 

IF depletes glycogen stores and promotes fat-burning, which helps push the body into ketosis. Exercising also burns up glycogen reserves in muscle tissue, which can accelerate the switch to using fat as a fuel source. 

Additionally, supplementing with electrolytes such as potassium, sodium, and magnesium, along with B vitamins, helps replenish nutrients depleted by carbohydrate intake. 

By ensuring these nutrients are replenished, you can better manage the negative effects of consuming refined carbs and support overall health and well-being.

Key takeaways

Carb cycling is a dietary approach originally used by athletes to build lean muscle mass and replenish glycogen reserves before events or intense training sessions. 

It’s also becoming popular among keto dieters to boost energy without feeling restricted. However, while carb cycling may temporarily increase energy, it can cause weight gain and poor metabolic health while negating the health benefits of a low-carb diet.

Although cheat days may seem tempting, it’s important to stick to your keto diet plan to maximize fat burning, maintain stable blood sugar levels, and achieve long-term health goals.

FAQ

1. Is carb cycling good for fat loss?

Yes, carb cycling can promote fat loss as it does limit carbohydrate intake on certain days. 

However, carb cycling won’t be as effective for weight loss as a consistent low-carb ketogenic diet, which pushes the body to utilize fat as a primary energy source instead of relying on sugar and carbs.   

2. What is an example of carb cycling?

An example of carb cycling involves consuming low-carb meals during the weekdays and switching to high-carb meals on the weekends.

Athletes may base carb cycling on their workout schedule, such as by reducing carb intake on rest days and eating high-carb meals before training sessions.

3. How long does it take to see the results of carb cycling?

Carb cycling may help you lose fat in as little as two weeks, as long as you’re in a calorie deficit. However, it’s not the most efficient method to lose weight and may be detrimental to metabolic health and performance levels. 

A Healthy Keto® diet in combination with intermittent fasting (IF) is an excellent strategy to support healthy body weight while promoting metabolic flexibility, sustained energy levels, and athletic performance.

4. What is 5/2 carb cycling?

5/2 carb cycling is a dietary approach that involves eating low-carb for five days a week and high-carb for two days to manage carbohydrate intake. 

This method aims to maximize the health benefits of both low-carb and high-carb diets, such as promoting fat-burning during low-carb days and replenishing glycogen stores during high-carb days.

5. Can I have a cheat day on keto?

It’s generally not advised to have a cheat day on keto, as constant adherence to a high-fat diet has the most profound health effects. However, having a cheat day after being fully fat-adapted may not be as detrimental as it is for those new to keto.

6. What are the downsides to carb cycling on keto?

The main downside to carb cycling on keto is that it will kick you out of ketosis if you consume more than 50 grams of carbs. This can lead to mood swings, carb and sugar cravings, and fatigue while slowing down weight loss.

Sources

1. https://www.dietaryguidelines.gov/sites/default/files/2020-2025 

2. https://pubmed.ncbi.nlm.nih.gov/28399015/