How carb cycling works and how to do it
If using carb cycling for fat loss, ensure that your protein intake is adequate and you maintain a calorie deficit.
What Is Carb Cycling, and How Does It Work?
Carb cycling involves adjusting your carbohydrate intake over a set interval of time. It may help you lose fat or maintain physical performance while supporting weight loss goals.
Carbohydrate intake has been a hot topic for a long time.
Several successful diets restrict carbs, and some even totally exclude them ( 1 , 2 , 3 ).
But no macronutrient is categorically bad, including carbs. Your carb intake is something that should be tailored to you as an individual ( 4 ).
In order to make changes to their overall carb intake, some people now “cycle” their carbohydrates.
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This is known as carb cycling.
This article provides a detailed breakdown of the science and application of carb cycling.
Carb cycling is a dietary approach in which you alternate carb intake on a daily, weekly, or monthly basis.
People may use it to lose fat, maintain physical performance while dieting, or overcome a weight loss plateau.
Some people adjust their carb intake from day to day, while others may do longer periods of low, moderate, and high carb intake.
In short, carb cycling aims to time carbohydrate intake to when it provides maximum benefit and exclude carbs when they’re not needed ( 5 , 6 ).
You can program your carb intake based on a variety of factors, such as:
- Body composition goals: Some people will reduce carbs during a diet and then add them back during a “muscle building” or performance phase.
- Training and rest days: One popular approach is a higher carb intake on training days and a lower carb intake on rest days.
- Scheduled refeeds: Another popular approach is to do 1 day or several days at a very high carb intake as a “refeed” during a prolonged diet.
- Special events or competitions: Athletes will often “carb load” prior to an event, and many physique competitors will do the same before a bodybuilding show or photoshoot.
- Type of training: Individuals will tailor carb intake depending on the intensity and duration of a particular training session. The longer or more intense the training is, the more carbs they will consume, and vice versa.
- Body fat levels: Many individuals will cycle their carbohydrates based on their level of body fat. The leaner they become, the more high carb days or blocks they include.
A typical weekly carb cycling diet may include 2 high carb days, 2 moderate carb days, and 3 low carb days.
Protein intake is usually similar from day to day, whereas fat intake varies based on carb intake.
A high carb day usually means low fat, whereas low carb days are high fat.
Carb cycling is an advanced diet strategy requiring more manipulation and programming than a typical diet. To get it right, it’s helpful to consult a registered dietitian.
Summary
Carb cycling is a dietary approach in which you manipulate your carb intake depending on a variety of factors.
Carb cycling is a relatively new dietary approach.
The science is primarily based on the biological mechanisms behind carbohydrate manipulation.
Few controlled studies have directly investigated carb cycling diets ( 7, 8 ).
Carb cycling is an attempt to match your body’s need for calories or glucose. For example, it provides carbohydrates around your workout or on intense training days.
The high carb days also help your body replenish its supply of muscle glycogen, which may improve performance and reduce muscle breakdown ( 9 , 10 ).
Strategic high carb periods may also improve the function of the weight- and appetite-regulating hormones leptin and ghrelin ( 11 , 12 ).
The low carb days reportedly switch your body to a predominantly fat-based energy system, which may improve metabolic flexibility and your body’s ability to burn fat as fuel in the long term ( 8 ).
Another big component of carb cycling is the manipulation of insulin ( 13 ).
The low carb days and targeting of carbs around workouts may improve insulin sensitivity, a vital marker of health ( 14 ).
In theory, this approach may support the benefits that carbohydrates provide.
Although the mechanisms behind carb cycling support its use, it’s still advisable to be cautious about this approach because of the lack of direct research. Many more clinical studies with human participants are needed to find out whether carb cycling is safe and effective.
Summary
The proposed mechanism of carb cycling is to maximize the benefits of carbohydrates and teach your body to burn fat as fuel. While this makes sense in theory, more direct research is needed.
The mechanisms behind carb cycling suggest that it can be beneficial for weight loss.
In theory, carb cycling may help you maintain physical performance while encouraging your body to burn fat for energy.
As with any diet, the main mechanism behind weight loss is a calorie deficit, meaning that you eat less than your body burns over a prolonged period ( 15 ).
If you implement a carb cycling diet alongside a calorie deficit, then you will likely lose weight.
However, the complex nature of carb cycling may cause confusion and make it difficult for beginners to stick to the plan.
In contrast, many people may enjoy the flexibility of carb cycling. This could probably improve adherence and long-term success for some people.
Summary
Carb cycling may help you lose weight, as long as you maintain a calorie deficit.
Many people believe that carb cycling can be beneficial for muscle gain and physical performance.
The regular high carb periods and targeted carb intake may help improve performance ( 9 ).
Consuming carbs around workouts may also aid in recovery, nutrient delivery, and glycogen replenishment ( 16 , 17 ).
This may promote muscle growth. However, some research suggests carbs are not necessary to build muscle if protein intake is sufficient ( 18 ).
While these mechanisms make sense in theory, direct research comparing carb cycling to other diets is needed to provide an evidence-based answer.
In addition, not all research supports the idea that “carb loading” improves athletic performance or muscle growth ( 19 ).
Overall, there isn’t enough data to know for sure ( 20 ).
Summary
The mechanisms behind carb cycling suggest it can help you optimize performance. However, further research is required.
As mentioned earlier, carb cycling has the potential to provide some benefits.
By having periods of both low and high carb consumption, you may get many of the benefits of both diets, as well as the potential negatives.
Benefits of low carb periods may include improved insulin sensitivity, increased fat burning, improved cholesterol levels, and enhanced metabolic health ( 8 , 14 , 21 , 22 ).
High carb refeeds may have positive effects on hormones during a diet, including thyroid hormones, testosterone, and leptin. High carb periods could also reduce inflammation and help your body use iron ( 12 , 16 , 23 ).
These factors may play an important role in long-term dieting success since hormones play a key role in hunger, metabolism, and exercise performance ( 24 ).
There may also be downsides to carb cycling. For starters, a complex diet can be hard to maintain. It’s also unclear whether any potential benefits will be long lasting. Plus, there isn’t enough evidence to know whether carb cycling is safe for your health over time ( 4 ).
Summary
Low carb periods may provide a number of health benefits, and high carb refeeds can have positive effects on your hormones. The long-term effects of carb cycling are not known.
There are many variations of carb cycling, including daily alterations or longer periods of high and low carb intake.
Here is a sample week in which you regulate your carb intake on a daily basis:
| Exercise | Carb intake | Fat intake | Amount of carbs | |
|---|---|---|---|---|
| Monday | weight training | high | low | 200 g |
| Tuesday | aerobic exercise | moderate | moderate | 100 g |
| Wednesday | rest day | low | high | 30 g |
| Thursday | weight training | high | low | 200 g |
| Friday | weight training | high | low | 200 g |
| Saturday | rest day | low | high | 30 g |
| Sunday | rest day | low | high | 30 g |
Even more so than a typical diet, carb cycling can take a lot of fine-tuning and adjustment along the way.
You can experiment with the number of high carb days per week and the number of grams of carbs per day to find the best approach for your lifestyle, exercise routine, and goals.
If you prefer a low carb diet, you can add carb cycling occasionally in the form of a refeed. Here are some sample low carb plans with occasional high carb blocks:
| Low carb period | High carb period | Amount of carbs in high carb period |
|---|---|---|
| days 1–11 | days 12, 13, 14 | 200–400 g per day |
| week 1–4 | week 5 | 150–400 g per day |
As the table suggests, you can either refeed every couple of weeks or do long periods, such as a 4-week low carb phase with a 1-week refeed.
You will also notice that the number of carbs per day can vary drastically — this depends on activity level, muscle mass, and carbohydrate tolerance.
An athlete who trains 3 hours a day or a 250-pound bodybuilder may need the upper limit (or even more), whereas an individual with a more moderate fitness level may need to refeed on only 150–200 grams.
These examples are only suggestions. There is no proven formula or ratio for carb cycling. The best option is to consult a registered dietitian to make a plan that’s tailored for you. Some dietitians specialize in making diet plans for athletes.
If you take any medications or have any health conditions, it’s important to talk with your doctor before making major changes to your diet. Carb cycling may not be appropriate for people with diabetes.
Summary
There are several options for carb cycling, ranging from daily changes to monthly refeeds. Consult a registered dietitian to figure out what works best for you and your goals.
Here are three sample meal plans for low, moderate, and high carb days. Keep in mind that the total carbs per meal in these samples are estimates, not exact numbers. Consider working with a dietitian to draw up a more precise plan that meets your particular needs.
High carb day
- Breakfast: 3 boiled eggs, 3 slices Ezekiel (or 7-seed/grain) bread, tomatoes, mushrooms, and a side of mixed fruit (60 grams of carbs)
- Lunch: 6-ounce (oz.) sweet potato, 6 oz. lean meat or fish, mixed vegetables (45 grams of carbs)
- Pre-workout: 1 serving oatmeal, almond milk, 1 cup berries, 1 scoop whey protein (50 grams of carbs)
- Dinner: 1 serving brown rice, 6 oz. lean chicken, homemade tomato sauce, 1 serving kidney beans, mixed vegetables (70 grams of carbs)
Moderate carb day
- Breakfast:high protein yogurt, 1 cup mixed berries, stevia, 1 spoon seed mix (25 grams of carbs)
- Lunch: 6 oz. chicken salad with 4 oz. diced potatoes (25 grams of carbs)
- Pre-workout: 1 banana and whey protein shake (30 grams of carbs)
- Dinner: 1 serving sweet potato fries, 6 oz. lean beef, homemade tomato sauce, 1 serving kidney beans, mixed vegetables (40 grams of carbs)
Low carb day
- Breakfast: 3 eggs with 3 slices bacon and mixed vegetables (10 grams of carbs)
- Lunch: 6 oz. salmon salad with 1 spoon olive oil (10 grams of carbs)
- Snack: 1 oz. mixed nuts with 1 serving turkey slices (10 grams of carbs)
- Dinner: 6 oz. steak, 1/2 avocado, mixed vegetables (16 grams of carbs)
Some carbs should be enjoyed in moderation, including simple sugars and refined carbs, which are found in foods such as cakes, desserts, highly processed snack foods, and baked goods.
In contrast, there are plenty of healthy carb sources that are tasty and packed full of beneficial fiber, vitamins, and minerals.
When planning your high carb days, focus on these healthier carb choices.
Recommended carbs
Instead of labeling carbs as “good” or “bad,” consider choosing unrefined carbs whenever possible. These include:
- Whole grains: Unmodified grains are perfectly healthy and may have many health benefits. Examples include brown rice, oats, and quinoa.
- Vegetables: Every vegetable has different vitamin and mineral content. Eat a variety of colors to get a good balance.
- Whole fruits: As with vegetables, every fruit is unique, especially berries, which have high antioxidant content and low glycemic load.
- Legumes: These are a great choice of slow-digesting carbohydrates, which are full of fiber and minerals.
- Tubers: This category includes potatoes and sweet potatoes.
Summary
Limit refined carbs and added sugars. Instead, eat mostly whole foods that contain plenty of fiber.
Carb cycling may be a useful tool for those trying to optimize their diet, physical performance, and health.
Some research supports the individual mechanisms behind carb cycling, although some evidence is mixed. More importantly, no direct research has investigated a long-term carb cycling diet in humans.
Rather than a long-term low or high carb diet, a balance of the two may be beneficial from both a physiological and a psychological perspective.
If using carb cycling for fat loss, ensure that your protein intake is adequate and you maintain a calorie deficit.
You may want to consider working with a dietitian to find a protocol and carbohydrate amounts that are the best fit for you. And if you take any medications or have health conditions such as diabetes, it’s important to consult your doctor before changing your diet.
Last medically reviewed on August 4, 2022
How we reviewed this article:
Our experts continually monitor the health and wellness space, and we update our articles when new information becomes available.
How carb cycling works and how to do it
Carb cycling is a diet where people consume more or fewer carbs over alternate days.
Carb cycling may have several benefits, such as helping people lose weight, increasing their athletic performance, and managing symptoms of chronic conditions.
This article will discuss what carb cycling is, how to do it, and some of the diet’s benefits.
Carbohydrates are an important source of calories and energy for most people.
There are two types of carbohydrates: simple carbs and complex carbs.
Simple carbs contain one or two sugar molecules, while complex carbs have three or more.
Complex carbs include starches, such as cereals, legumes, and potatoes.
Carb cycling is a dietary plan where people alternate their carb intake daily, weekly, or monthly.
For example, some people may have a high carb and low fat diet some days and consume a diet low in carbs and high in fat on other days.
Carb cycling is a diet that people can modify to suit their needs. However, it may involve more planning than others.
There is some evidence that carb cycling may help with weight loss, health conditions such as type 2 diabetes.
A 2013 study suggests that intermittent energy and carbohydrate restriction may improve insulin sensitivity and weight.
The participants, whose energy and carbohydrate restriction was intermittent at 2 days per week, were split into two groups. Researchers allowed one group to consume protein and fat as desired but restricted their overall carbohydrates and energy.
The group who were allowed to consume protein and fat as desired saw a similar number of participants experience 5% or greater weight loss.
The study also found that participants continued to have a reduction in insulin resistance, body fat reduction, and a decrease in the hormone leptin at the end of 4 months of following the diet.
This study suggests that there may be benefits to following a carb cycling diet.
Carb cycling aims to help people with their weight and fitness goals by alternating between low and high carb days.
A diet low in carbs can offer a variety of benefits.
People who follow a low carb diet tend to consume more proteins and fats that can make them feel full for longer. This also limits hypoglycemia, which in turn reduces hunger and calorie intake.
Diets high in nutrient-dense carb sources, such as vegetables and fruit, also have their benefits. Consuming meals high in fiber-rich carbs that include vegetables and fruits may reduce the risk of developing type 2 diabetes. Additionally, there is evidence that high carb diets increase insulin sensitivity in individuals with type 2 diabetes.
Eating fiber-rich carbohydrates may also lower cholesterol. This, in turn, may decrease the risk of heart disease.
The theory behind carb cycling is that people benefit from both high and low carb diets by alternating between these diets on a daily, weekly, or monthly basis.
There is some evidence that low carb diets help with weight loss and may speed up metabolism.
Healthy high carb diets may also be beneficial because they reduce the risk of type 2 diabetes, heart disease, and intestinal cancer.
While there are benefits to both nutritious high and low carb diets, there are few scientific research papers available on carb cycling.
Anecdotally, carb cycling may be able to help people lose weight. However, there is currently no scientific research that suggests carb cycling is more or less effective for weight loss than other diets.
If people consume enough calories for their body weight, if they are a moderate weight, or have a slight calorie deficit if they have a high BMI, carb cycling may help them lose weight or maintain a moderate weight.
Research suggests there is no significant difference in weight loss between diets that restrict one form of macronutrient, such as protein or carbs, over another.
A 2018 study suggests diets that allow people to tailor food consumption and the type of food to their individual needs and preferences tend to experience better diet adherence and weight loss.
Carb cycling does not restrict a person’s consumption of types of food as much as some other diets. Some people may find this approach more suitable for their needs and therefore may find this diet helps them with weight loss.
The National Institute of Diabetes and Digestive and Kidney Diseases offer a free body weight planner, which may help people plan how many calories they consume in their carb cycling diet.
There is some evidence that low carb diets, such as carb cycling, may be beneficial for muscle gain and sports performance.
A 2017 study suggests that competitive bodybuilders who utilize carbohydrate refeeds, which are periods of times where they consume more carbs, do so because they believe it enhances fat loss.
Participants in the study stated that carbohydrate refeed days increased glycogen stores. They also noticed that these days aided their training performance and helped them mentally recover from their exercise regimes.
However, researchers need to conduct more studies to investigate the safety and effectiveness of carb cycling within the sports fitness community.
There is currently no scientific research on the health benefits of carb cycling.
It is important to consume the correct number of calories for a person’s daily requirements regardless of their diet.
It is also vital to consume enough macronutrients and micronutrients. Without sufficient quantities of these nutrients, an individual puts themselves at risk of developing undernutrition .
There are many variations to carb cycling, with people practicing programs on a daily, weekly, or monthly basis.
The amount of carbs that individuals eat per day will depend on whether they are consuming a high, moderate, or low carb meal. Examples of daily carbohydrate loads include :
- Very low carbohydrates: Under 10% of a person’s daily calories will come from carbs.
- Low carbohydrates: Under 26% of a person’s daily calories will come from carbs.
- Moderate carbohydrates: Between 26–44% of a person’s daily calories will come from carbs.
- High carbohydrate: 45% or more of a person’s daily calories will come from carbs.
An example of a weekly carb cycling diet, based on a person who needs 2,000 calories a day, is below.
| Day | Carb intake | Fat intake | Amount of carbs |
|---|---|---|---|
| Monday | High carb | Low fat | 225 g |
| Tuesday | Moderate carb | Moderate fat | 130 g |
| Wednesday | Low carb | High fat | 75 g |
| Thursday | High carb | Low fat | 225 g |
| Friday | High carb | Low fat | 225 g |
| Saturday | Low carb | High fat | 75 g |
| Sunday | Low carb | High fat | 75 g |
Each gram (g) of carbohydrates contains 4 calories.
