This Eating Plan Promises Fat Loss & Blood Sugar Balance — Is It Worth It?

Often advertised as an "easier alternative" to low-carb dieting, carb cycling is a (still very restrictive) eating pattern that switches between high-carb and low-carb days throughout the week. But does it really live up to its promises of promoting fat loss and managing blood sugar?

We dug into the existing research on carb cycling to make a judgment call on whether it's actually worth trying, how to do it healthily, and who should avoid it and opt for a more flexible approach instead.

Carb cycling is an eating pattern that involves cycling between low-carb and high-carb days. It's rooted in the competitive weightlifting world. Bodybuilders have long used it as a way to deplete glycogen stores, lose water weight, and optimize exercise performance right before an event.

Over the past few years, as low-carb eating patterns like the ketogenic diet have soared in popularity, carb cycling has become more mainstream.

“Carb cycling is a tool often used for people following a lower-carb diet eating plan like a ketogenic diet that involves alternating the amount of carbohydrates that you consume on different days,” explains Will Cole, IFMCP, DNM, D.C., a functional medicine practitioner.

According to Cole, a typical 7-day carb cycling plan might involve cutting your carb consumption for five or six days and then increasing your intake one or two days per week. For athletes, high-carb days often align with their training plan to provide extra fuel for high-intensity or endurance workouts.

Proponents of carb cycling claim that it can promote weight loss, boost energy levels, and even enhance insulin sensitivity. Plus, some note that it can be a more manageable approach to low-carb eating plans by allowing you to enjoy your favorite high-carb foods a few times per week.

On the other hand, some note that carb cycling can still be overly restrictive and might not be a good fit for everyone.

Summary

Carb cycling involves switching up the amount of carbs that you consume on different days of the week. Typically, people have 5-6 "low-carb" days and 1-2 "high-carb" days a week. This strategy has long been used by professional athletes to train for events, but it's now being more widely adopted as a weight loss and blood sugar management tool.

1.

You’re following keto but have hit a plateau.

“Carb cycling is not the first option that I recommend if you are just starting out on a ketogenic diet, but it can be a great approach for some people who've reached a plateau in their health,” Cole tells mindbodygreen.

This approach, sometimes called "keto cycling," involves following a high-fat, low-carb diet, but taking a day or two off each week to cycle in and out of ketosis, a metabolic state in which your body burns fat for fuel instead of sugar.

Keto cycling is a relatively new concept, meaning there’s not a lot of research on whether or not it’s actually effective. However, proponents claim that it can make it easier to stick to a keto diet, which could translate to greater weight loss and health benefits long-term.

If you’ve been trying keto for a while but have hit a plateau, consider taking a closer look at your diet and recalculating your macronutrient requirements to adjust as needed. Some people may also find that following a more relaxed approach (such as the lazy keto diet) or even simply cutting back on carbs can be more sustainable ways to lose weight and keep blood sugar levels steady.

2.

You’re an athlete looking to maximize your performance

3.

You’re interested in eating for your menstrual cycle.

According to Cole, carb cycling might be especially beneficial for women. He explains that your body requires more carbs during certain parts of your cycle and recommends increasing your intake of fiber-rich carbs around menstruation and ovulation.

Although research in this area is still pretty limited, science does show that dietary intake definitely does fluctuate throughout the menstrual cycle. This might be due to changes in hormone levels like estrogen and progesterone, which can affect appetite, coupled with variations in the breakdown of carbs, fat, and protein at different points in your cycle.

Your body might also have a higher tolerance for carbs during the first half of your cycle, meaning that the period from menstruation to ovulation is the best time to consume carbs.

Of course, everyone is different and your carb cravings might peak at different points in your cycle, so your mileage may vary here. If carb cycling isn’t for you, simply listening to your body and following a balanced diet throughout your cycle can be a good tried-and-true alternative.

4.

You’re looking to lose fat or gain muscle.

With carb cycling, your protein intake should remain steady (here's how to calculate your ideal protein intake), while your fat intake might fluctuate depending on your daily carb goals.

You should adjust your daily carb goals to fit your daily calorie needs. Shapiro recommends using an online calculator to determine your unique target calorie intake and then subtracting the amount of protein and fat that you need to determine your carb requirements for high-carb days.

“From there, your moderate-carb days are 15-20% less than that number, and your low-carb days are 20-25% less than your moderate carb day number,” she explains.

Low-carb diets typically contain less than 130 grams of carbs, or less than 26% of total calories from carbs per day.

Here’s what a typical week might look like on a carb cycling routine:

1.

Stick to high-quality carbs.

Although carb cycling is all about sticking to a specific amount of carbs each day, Cole emphasizes that not all carbs are created equal.

Opting for healthy high-carb foods like vegetables, potatoes, brown rice, and beans can help squeeze more carbs into your diet while also bumping up your intake of other important nutrients like fiber, vitamins, and minerals.

“Refined sugar and other processed carbs come with their own list of downsides for your health that can ultimately negate the benefits you are trying to achieve from carb cycling in the first place,” says Cole.

2.

Focus on the bigger picture.

3.

Don't be afraid to experiment.

“There are a variety of ways to do carb cycling, from daily carb consumption changes to weekly carb refeeding schedules,” Shapiro tells mindbodygreen. “The most important part is to see which cycle works best for you, as carb cycling takes a lot of time and commitment.”

Shapiro recommends committing to a carb cycling schedule and training plan for at least one full cycle to decide whether it’s a good fit. If it’s too difficult to maintain or it’s just not working out, switch up your schedule and try again to find what works for you.

4.

Loosen up the rules as needed.

5.

Consult with a professional.

One of the biggest criticisms of carb cycling is that it isn't enough science to support its efficacy. For example, according to one review of 49 studies published in Nutrients in 2022, while some studies found that increasing carb intake could help improve performance after depleting glycogen stores, other studies found no benefits of carb cycling.

Critics of carb cycling also point out that carbs serve as the body’s primary source of energy, meaning that decreasing your intake on a regular basis might leave you feeling sluggish and drained—the exact opposite of what you want.

Without proper planning, carb cycling can also make it more difficult to meet your nutritional needs, which may ultimately negate any potential benefits.

Additionally, from a dietitian's perspective, carb cycling can be quite challenging to sustain in the long run, notes Shapiro. Meticulously tracking your macronutrient intake daily can be pretty taxing, and it may even negatively impact mental health in some people. “[Carb cycling] might lead to obsessive thoughts about food, which can lead to future eating disorders,” cautions Shapiro.

Summary

Critics of carb cycling note that the scientific research on it is very limited (and mixed), and the eating pattern may be too restrictive for some people. There is also the risk that being so laser-focused on your carbohydrate intake will cause you to neglect other important macronutrients, like protein.

At the end of the day, scientific literature on carb cycling is pretty limited. And while there is some research to support carb cycling in some cases—including for promoting weight loss or athletic performance—a lot of studies have turned up conflicting results, and it’s unclear whether or not it’s any more effective than other eating patterns.

For this reason, we don't endorse carb cycling as a weight loss or athletic performance tool. Many factors can influence how people (particularly women) process carbohydrates and it's important to take this bio-individuality into account when making food choices.

Carb cycling is also far from the only way to lose fat or build muscle mass. Reducing your calorie intake, staying active, and reducing your portion sizes are a few more flexible strategies that can help you lose weight, with no carb counting required. Similarly, ramping up your protein intake can effectively increase muscle growth when combined with resistance training.

That being said, if you like a challenge or want to use carb cycling as a way to make the keto diet more approachable, by all means, try it. Just be sure to prioritize nutrient-dense carbs and continue to eat enough protein and healthy fat while you do. And if you do find carb cycling too difficult to maintain, no shame: switch up your schedule and try again to find what works for you.

Summary

We don't endorse carb cycling as a weight loss or athletic performance tool, as there are less restrictive ways to lose fat and gain muscle based on your unique dietary needs. With that being said, as long as you're prioritizing healthy carbs, there shouldn't be any harm in trying carb cycling for most people.

Cutting your carb consumption may cause some negative side effects, including fatigue, hunger, constipation, and bloating.

These symptoms, sometimes known as the “carb flu” or “keto flu” are common any time you start a low-carb diet, but typically clear up quickly as your body adapts. However, this might take a little longer with carb cycling, as you’re alternating between high-carb and low-carb days without giving your body time to adjust.