Eating too many carbs? Or not enough? Carb cycling calculator can help you optimize your carb intake for your weight and fitness goals.

But it’s not as easy as simply cutting carbs some days and overloading on them on others.

In this post, we show you how to carb cycle and what food to add to a low-carb diet meal plan. We also feature a step-by-step guide to a carb cycling macros calculator.

Ready when you are!

In This Article

What Is Carb Cycling?

Carb cycling is an approach to dieting that varies your carbohydrate intake on a daily or weekly basis. When you carb cycle, you eat fewer carbs on some days, like when you don’t exercise. And more carbs on other days, such as on workout days.

Carbs elevate blood sugar levels. In response, your pancreas makes more insulin. Insulin takes glucose into cells for it to fuel your body. Or to be stored for later use as glycogen.

A high-carb intake leads to an overproduction of insulin. This increases the risk of weight gain, diabetes, and cardiovascular disease. Cycling carbs by reducing your carb intake helps your body burn fat instead of carbs.

One carb provides 4 calories per gram. By cutting down on carbs, you reduce your caloric intake and run a caloric deficit. Carb cycling can help you lose weight.

However, cutting back on carbs usually means adjusting other macronutrients to meet the minimum caloric intake. In other words, eating more fat and protein.

Protein plays a key role in muscle building and maintenance. You need enough protein every day regardless of your carb or fat intake.

Carb cycling isn’t just about cutting back on carbs. It’s also about carb loading on days when you need it. For example, before a long and intense workout or a long-awaited half-marathon.

Reasons Behind Using Carb Cycling

From losing weight and fat to boosting your athletic performance, the reasons behind carb cycling can be persuasive.

  • Lose weight. Low-carb diets can promote weight loss. Since carbs are a significant source of calories, reducing carbs means you take in fewer calories.
  • Reduce fat. Cutting down on carbs lowers your blood glucose levels. With less sugar in the bloodstream, your body produces less insulin and burns more fat for energy.
  • Enter ketosis. Reducing carbohydrate intake while increasing fat intake for several weeks induces ketosis. During this state, the body starts using fat stores as fuel. The ensuing keto-adaptation may provide a performance boost during endurance exercise, according to a 2015 study.
  • Improve health. There is some evidence that carb cycling can reduce blood sugar levels. It may also improve insulin resistance and lower cholesterol levels.
  • Improve performance. Your body needs ample glycogen stores to sustain long and intense physical activity. Without enough carbs, you will underperform. Carb cycling can involve carb loading on days when you need it the most. Like before a running event.

Benefits of Carb Cycling

Research shows that a carb cycling diet can suppress hunger and improve insulin resistance. It can also speed up fat burning and give you a performance boost. Let’s take a closer look at the benefits of carb cycling.

Suppressing hunger

Eating high-fat, high-protein meals increases satiety after a meal compared to eating a high-carb meal, according to research. It also helps regulate hunger hormones.

However, a study in healthy females found that carb overfeeding increased leptin levels. Leptin is a hormone that regulates energy balance by reducing hunger.

Another study suggests that a low-carb diet can help preserve satiety better than a low-fat diet. A 2018 study on obese insulin-resistant men had similar findings. It concluded that a high-protein or high-fat meal improves satiety more than a carb-rich meal.

The bottom line is that reducing your carb intake while increasing your fat intake will likely make you less hungry.

Fat loss

Findings from a randomized controlled trial show that a diet that reduces carbs promotes notable weight loss. The same is true for diets that cut other macronutrients such as fat or protein. The result is due to the reduced calorie intake.

Insulin health

When you eat fewer carbs, your body produces less insulin. Suppressing insulin can reduce weight, fat mass, and food cravings, according to a study on obese adults.

Insulin also affects blood pressure and renal sodium levels, which may be risk factors for cardiovascular disease. Foods with a high sugar content, especially fructose sugars such as sucrose and corn syrup, are linked with a higher risk of cardiovascular disease.

What’s more, fructose is less likely to suppress appetite than glucose. It may also be addictive, making you eat more sugary foods. More than a higher risk of heart disease, added sugar increases the risk of digestive and esophageal cancers.

Increased fat burning

Even a modest reduction in carbohydrate intake can reduce weight, decrease fat, and accelerate glucose metabolism, a 2015 study found.

A 2009 controlled trial indicates that a low-carb diet improves metabolic syndrome better than a low-fat diet. Metabolic syndrome refers to a combination of diabetes, hypertension, and obesity. At the same time, it also decreased cardiovascular risk.

Lower cholesterol

A low-carb diet can improve cholesterol levels by boosting beneficial HDL cholesterol and decreasing bad LDL cholesterol. However, research indicates that it may also increase triglycerides, a possible risk factor for cardiovascular disease.

Performance boost

Significantly increasing your carbohydrate intake before, during, and after intense, prolonged exercise may support performance. Intense, prolonged exercise, such as long-distance running, depletes glycogen stores in the muscles and liver.

Glucose, together with protein, help restore glycogen levels in the muscles.

A study suggests that taking in 600 grams of carbs within 24 hours, with 200 grams in a 4-hour timeframe before exercise, helps keep the body geared for optimal performance.

A 2021 controlled trial found that following a high-carb/low-fat diet for 3 weeks led to higher peak performance during exercise. It also increased the time to exhaustion.

Other studies suggest that carb loading can boost performance during high-intensity training and short runs.

Should You Use Carb Cycling?

More research is needed to understand the long-term effects of carb cycling. According to the Mayo Clinic, carb cycling is “generally safe for a short time.”

Carb cycling may be more effective at helping you lose weight while training intensively than following a low-carb diet. By alternating low-carb days with carb loading, you can provide your body with energy when it needs it the most.

It also prevents your body from adapting to consistently low-carb levels. This adaptation may lead to the secretion of less leptin and decreased metabolism.

That said, carb cycling is challenging and requires discipline. You need to understand macronutrients and make smart food choices. Otherwise, you may be depleting your body of essential nutrients.

If you have any medical condition, including diabetes and heart disease, discuss carb cycling with your doctor first.

If you are healthy and want to give carb cycling a go, a carb cycle calculator can make your life easier.

How to Use a Carb Cycling Calculator

Effective carb cycling calls for some calculations, so dust off your math skills. You have to figure out how many carbs to eat on both low-carb and high-carb days. Follow the steps below to create a personalized carb cycling diet.

Step 1

First, calculate how much energy your body needs to survive, or the basal metabolic rate.

Female BMR = 655 + (9.6 x your weight in kg) + (1.7 x your height in cm) – (4.7 x your age)

Male BMW = 66 + (13.7 x your weight in kg) + (5 x your height in cm) – (6.8 x your age)

Step 2

Next, factor in your physical activity level. Multiply your BMR by the corresponding daily activity level factor.

Activity level/activity factor

  • Sedentary/1.0
  • Very light activity/1.2
  • Light activity/1.4
  • Moderate activity/1.6
  • High activity/1.8
  • Extreme activity/2.0

Step 3

Now you have to determine how much protein and fat you need to take in. Convert the total grams of protein or fat you need into a calorie number.

  • Daily fat goal = 9 calories per gram x (Your body weight x 0.30 grams of fat)
  • Daily protein goal = 4 calories per gram x (Your body weight x 0.30 grams of fat)

After adding these numbers, subtract your total calorie intake from them and divide the result by four.

Tip: Protein and carbs are the key macros for muscle gain.

Step 4

Next up, you have to figure out your carb cycling intake.

  • High-carb day. This is the intake you’ve calculated using the steps above.
  • Medium-carb day. Lower your carb intake by 15–20%. To calculate this, multiply your high-carb intake by 0.8 and then by 0.85.
  • Low-carb day. Lower your medium-carb intake by 20–25%. Multiply the medium-carb intake by a factor of 0.75 and 0.8.

Sounds like a lot of math? You can find carb cycling calculators online that can do the math for you.

Carb Cycling Calculator Example

Now let’s see the carb cycling calculator in action. In this example, we’ll be using a 30-year-old female runner who weighs 60 kilograms and is 175 centimeters tall. She engages in moderate physical activity.

First, the BMR:

655 + (9.6 x 60) + (1.7 x 175) – (4.7 x 30) = 1387.5

Then we factor in the activity level:

1387.5 x 1.6 = 2220

Next, we calculate fat and protein breakdown:

Calories from fat: (60 x 0.30) x 9 = 162

Calories from protein: (60 x 1.15) x 4 = 276

This is how much fat and protein your body needs. If you have higher fat and protein targets, subtract the numbers above from them.

Next, add calories from fat and protein together. Subtract them from your total calorie intake to figure out how many calories you need to eat from carbs.

2220 – (162 + 276) = 1782

You can divide the result above by 4 to determine how many grams of carbs you need to take in.

1782 ÷ 4 = 445.5

This is how many grams of carbs you need to take in on a high-carb day.

On a medium-carb day, you’ll need…

445.5 x 0.8 = 356.4

445.5 x 0.85 = 378.6

Between 356 and 378 carbs.

On a low-carb day, you’ll need…

356.4 x 0.75 = 267.3

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378.6 x 0.8 = 302.88

Between 267.3 and 302.88 carbs.

Some Good Food Choices for Carb Cycling

Some carbs are healthier than others. Simple carbs are sugars and starches found in processed foods made with refined flour or added sugars. Think bread or pasta made with white flour, donuts, sweets, or soda.

By contrast, complex carbs have not been stripped of their fiber and have more nutrients. They occur in whole, unprocessed foods like whole grains, vegetables, fruits, and legumes.

Simple carbs can lead to spikes in blood sugar levels and have adverse health effects. Complex carbs are richer in nutrients and more filling.

Some of the best foods you can use when carb cycling include:

  • Whole grains such as brown rice, pasta, and quinoa
  • Oatmeal
  • Granola
  • Sweet potatoes
  • Beans and legumes
  • Dried fruits, including raisins, cranberries, plumes, and apricots
  • Plant-based milk

Exercising When You Are Carbohydrate Cycling

Carbs fuel your body. That’s why you want to match your carb cycling schedule to your activity level.

Planning a strenuous workout or a long and demanding run? Match that with a high-carb intake.

Similarly, for moderate-intensity activity, follow a medium-carb intake.

What you don’t want to do is cycle low carbs on days with tough workouts. You won’t have the energy to perform at your best.

Match low-carb intakes to low activity levels or rest days. That way, your carb cycling plan won’t get in the way of your performance.

Word of Caution – Are There Any Side Effects to Carb Cycling?

Your body needs carbs to function normally. Adjustments in your carb intake, especially when significant, may cause a variety of side effects.

The most noticeable in the case of a low-carb intake is low performance during exercise. Other side effects may include a lack of vitality, dizziness, headaches, irritability, stomach problems, and trouble sleeping.

Carb loading can spike your blood sugar levels, especially if you’re eating simple carbs. This, in turn, may increase the risk of type 2 diabetes and cardiovascular disease. It may also promote acne.

Weight gain is another obvious side effect of consuming too many carbs.


Before you start carb cycling, here are the things to remember.

  • Carb cycling for weight loss doesn’t bring overnight results.
  • However, it can fuel your body during tough workouts while helping you cut back on carbs on low-activity days.
  • Calculating your macronutrient intake is crucial to get carb cycling right.
  • Eat healthy carbs to prevent blood sugar spikes.
  • Monitor the effects of your carb cycle diet and adjust it according to your goals.

Frequently Asked Questions

How do you calculate carb cycling?

Carb cycling involves alternating between high-carbohydrate days and low-carbohydrate days. The goal is to maximize your body’s ability to burn fat for fuel while still providing enough carbohydrates for optimal performance.

Calculating carb intake for low-carb days:

On low-carb days, aim to consume around 0.5 grams of carbohydrate per pound of body weight. For example, if you weigh 150 pounds, you would consume around 75 grams of carbohydrates per day.

Calculating carb intake for moderate-carb days:

On moderate-carb days, increase your carbohydrate intake to around 1-1.5 grams of carbohydrate per pound of body weight. For example, if you weigh 150 pounds, you would consume around 150-225 grams of carbohydrates per day.

Calculating carb intake for high-carb days:

On high-carb days, consume around 2-2.5 grams of carbohydrate per pound of body weight. For example, if you weigh 150 pounds, you would consume around 300-375 grams of carbohydrates per day.

What macros should I split for carb cycling?

A typical carb cycling plan involves splitting your macros into three phases: low-carb, moderate-carb, and high-carb.

Low-carb macros:

On low-carb days, aim for a ratio of 20-30% protein, 20-30% fat, and 50-50% carbohydrates.

Moderate-carb macros:

On moderate-carb days, aim for a ratio of 30-40% protein, 30-40% fat, and 30-40% carbohydrates.

High-carb macros:

On high-carb days, aim for a ratio of 40-50% protein, 20-30% fat, and 30-40% carbohydrates.

Sample carb cycling macros:

  • Low-carb day: 150 grams protein, 75 grams fat, 75 grams carbohydrates (20% protein, 20% fat, 50% carbohydrates)
  • Moderate-carb day: 180 grams protein, 90 grams fat, 180 grams carbohydrates (30% protein, 30% fat, 30% carbohydrates)
  • High-carb day: 210 grams protein, 60 grams fat, 330 grams carbohydrates (40% protein, 20% fat, 40% carbohydrates)

What is the best carb cycling schedule?

There is no one-size-fits-all carb cycling schedule, as the best plan for you will depend on your individual goals and preferences. However, a common approach is to follow a 4-day cycle, with two low-carb days, one moderate-carb day, and one high-carb day.

You can also adjust the frequency of your low-carb days based on your needs. For example, if you are trying to lose weight, you may want to have more low-carb days than high-carb days. Conversely, if you are trying to gain muscle, you may want to have more high-carb days than low-carb days.

What is the ratio for carb cycling?

The ratio of carbohydrates to other macros will vary depending on your individual needs and goals. However, a general guideline is to aim for a ratio of 40% carbs, 30% protein, and 30% fat. This is because carbohydrates are your body’s primary source of energy, protein is essential for muscle growth and repair, and fat is needed for hormone production and overall health.

It is important to experiment with different carb cycling ratios to find what works best for you. If you are not sure where to start, you can try a 40/30/30 split and adjust it as needed.


  • Dustin, M., 2016. The everything guide to the carb cycling diet: an effective diet plan to lose weight and boost your metabolism. Simon and Schuster.
  • Corapi, R., 2009. Carb-cycling results. Flex27(5), pp.44-45.
  • Malkov, R., 2012. The Carb Cycling Diet: Balancing Hi Carb, Low Carb, and No Carb Days for Healthy Weight Loss. Hatherleigh Press.
  • Nieman, D.C., 1998. Influence of carbohydrate on the immune response to intensive, prolonged exercise. Exercise immunology review4, pp.64-76.
  • Malkov, R. and Peck, P.F., 2005. The carb cycling diet: optimize your health, lose weight, feel great–without giving up the foods you love.
  • Velazquez, E., 2019. Turn an ordinary weight-loss diet into an extraordinary fat-burning plan with these 4 must-read nutritional upgrades!. Nutrition.
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Written by

Chris Zibutis

Chris Zibutis is the Head Running Coach and founder of Joggo – that one person on earth who loves interval runs.  He holds a degree from Copenhagen Business School and is an avid runner – having participated in numerous marathons and triathlons, Chris brings substantial fitness and running experience to the Joggo team.