What Is Carb Cycling?

When people are searching for ways to lose weight, sometimes they look to carbs for help.

There’s growing interest in something called carb cycling. It's a short-term diet once used mainly by athletes and bodybuilders. It’s a type of low-carb diet like the Atkins or keto diets. It's becoming popular because you might lose weight quickly, even though a lot of that weight would come from water. Once you stop relying on carbs to fuel your body, you might feel fewer carb cravings and have more energy.

The Scoop on Carbs

Carbohydrates are your body’s main source of energy. Your body needs them to work the way it should.

Carbs are found naturally in dairy products and in plant-based foods like beans, grains, fruits, and vegetables. They’re also added to processed foods, as sugars or starches.

Some carbs are healthier than others.

When you digest carbs, they break down into glucose, which your body uses for fuel.

What Is Carb Cycling?

Carb cycling is a very strict diet used by serious athletes and bodybuilders who want to drop body fat, get more muscle mass, or store more carbs for long-haul exercise like a marathon. Now, it’s becoming more popular with those who want to kick-start their weight loss.

It involves going back and forth between high-carb days and low-carb days. There may even be “no-carb” days.

You would usually have a high-carb day when you plan on exercising hard. On those days, your body needs more fuel, so you might eat 2 to 2.5 grams of carbs for every pound of body weight.

You eat fewer carbs on days when you’re less active. On low-carb days, you might eat .5 grams of carbs for every pound of body weight. You may even include a "no-carb" day, when you have less than 30 grams of carbs for the entire day.

Another option is to follow a plan where you spend 3 days eating a low amount of carbs -- about 100-125 grams each day. Then you spend 2 days eating a high amount of carbs (175-275 grams) on days you are more active.


How It Works

When you eat food that has carbohydrates, as your blood sugar goes up, your pancreas makes more of a hormone called insulin that takes glucose into cells. There, the glucose is either converted into energy, stored for later use, or turned into fat.

As cells take in blood sugar, the pancreas signals the cells to release stored glucose -- called glucagon. This back-and-forth makes sure the body has the right amount of sugar.

But when you eat a carb-heavy diet, your body can release too much insulin. That can lead to weight gain and a higher chance of things like type 2 diabetes and heart disease.

Taking short breaks to cycle carbs can give your body a chance to burn fat as fuel instead of burning carbs and muscle tissues for energy.

Is It Safe?

When you cut back on carbs for a few days, you might have:

This is called “carb flu,” and it usually doesn’t last long. Drinking water and electrolytes can help.

Because it is extreme, carb cycling should be used only for a brief time, and it’s not right for everyone.

You shouldn’t try it if you are:

Don’t try it if you have adrenal issues, either.

When in doubt, check in with your doctor before you start.

Choosing Smart Carbs

Here are some tips to help you pick the carbs that are best to eat:

  • Choose high-fiber fruits and vegetables.
  • Opt for low-fat milk, cheese, yogurt, and other dairy products.
  • Stock up on legumes, including beans, lentils, and peas.
  • Eat lots of whole grains.
  • Limit refined grains, added sugars, and highly processed foods.

WebMD Medical Reference Reviewed by Kathleen M. Zelman, MPH, RD, LD on January 15, 2020



Cleveland Clinic: “What to Eat if You’re Carb Cycling.”

American Council on Exercise: “Carb Cycling.”

Academy of Nutrition and Dietetics: “What is the Ketogenic Diet?”

Mayo Clinic: “Carbohydrates: How carbs fit into a healthy diet.”

Harvard School of Public Health: “Carbohydrates and Blood Sugar.”

© 2020 WebMD, LLC. All rights reserved.