Is Carb Cycling an Effective Dietary Approach?

How to eat carbohydrates and lose fat

Manipulating carbohydrate intake for improved weight loss, muscle gain, or athletic performance continues to be a popular trend. Our fitness goals and nutritional focus appear to center mostly around carbs and eating just the right amount. Several diets even eliminate this very important macronutrient as the only way to lose fat.

There is so much confusion about carbohydrates mostly because of restrictive and fad diets. Carbs are shown to be essential for health and body function, so removing them is not a good idea.

Applying healthy dietary approaches that include carbs is the best way to go. This means incorporating the right amount of carbohydrates to achieve desired results for each person. 

Carb cycling is considered a new dietary approach but has been popular among bodybuilders and athletes for some time. The diet method appears to be an effective way to eat carbs, lose fat, and improve your health.  

What Is Carb Cycling?

Carb cycling is a high-level nutrition strategy of alternating high and low levels of daily carbohydrate intake. It requires strict nutritional adherence and should only be used in short duration phases, according to Tony Maloney, an ACSM-certified exercise physiologist.

One of the goals of carb cycling is to force the body to use fat for fuel instead of glycogen (stored carbs or sugar). It appears performing exercise on low carb days can result in an increased ability to burn fat. However, reduced carbohydrates can also negatively affect exercise performance according to research.

There are several ways to carb cycle based on individual goals. The diet is split into phases of low and high carb days to maximize how your body uses carbohydrates. Basically, eat more carbs on days you are active, fewer carbs on rest days.

In order to cycle carbs in your diet, it’s necessary to figure out how many you should eat in the first place. This amount is determined and takes into consideration the following: 

  • Your age, weight, and height
  • Basal metabolic rate (BMR)
  • Activity level (sedentary, active, etc.)
  • Daily macronutrient breakdown (proteins/carbs/fats)

Typical carb cycling diets include high, medium, and low intake days. General guidelines are as follows:

  • Carbs decreased by 15–20 percent from the high carb day for medium days.
  • Carbs reduced by 20–25 percent from the medium carb day for low days.

Because carb cycling isn’t recommended for long-term weight management, you should only consider using it after exhausting basic diet strategies, suggests Maloney. 

How Does It Work?

Carb cycling has become a popular way for dieters to overcome weight loss plateaus. It’s also a method for bodybuilders and athletes to manipulate carbs for athletic goals.

The diet works by manipulating carbohydrate intake throughout the week. It also places the body in a caloric deficit on low carb days promoting weight loss.

The goal of carb cycling is to maximize the use of carbs or glycogen. There are two common methods according to Maloney and include:

  • Infrequent large “re-feed” of carbohydrates: Select a day following a 7-14 day period of low carb intake and consume significantly more carbohydrates. Refeeds are often used as rewards for being committed to the plan throughout the low carb phase. This can help with the psychology of the plan as well as bring the body close to starvation mode but not beyond it. The body is forced to adapt to the eating strategy. 
  • Frequent moderate re-feeds: One day is incorporated every 3 to 4 days of a low carb phase. An individual would consume a bit more carbohydrates on that day. This method could be more effective for those with less mental fortitude to stay away from the carbohydrates.

Note: You must exercise on re-feed days.

The purpose of low carb days is to promote weight loss, improve insulin sensitivity, and help the body burn fat for fuel.

High carb days are used to refuel your muscles, enhance athletic performance, and improve appetite-regulating hormones (leptin and ghrelin).

Is Carb Cycling Effective? 

A well-developed carb cycling plan done for a short duration can be effective, according to Maloney. The overall goal should be sticking to the plan while consuming higher quality whole foods and limiting processed foods and sugars.

Carb cycling does place the body in a caloric deficit shown to promote weight loss. However, the plan requires constant re-evaluation and calorie adjustment to prevent the body from adapting to this type of nutrition strategy.

Without adjusting a low carb phase diet, there is the potential for slowing chemical reactions regulating metabolism or appetite hormones. Slowing the appetite, slows the metabolism, and can lead to stalled weight loss.

High carb days help offset the body adapting to the program by boosting leptin hormone levels. Increased carbs are also shown to refuel your muscles, boost metabolism, and improve training levels.

Some people opt to incorporate cheat meals into their low carb diets as a form of carb cycling. Although not as precise as carb cycling, it can serve the purpose of boosting leptin levels and regulating metabolism.

Is It for Everyone?

Carb cycling can be for everyone if used properly and for a short amount of time, according to Maloney.

Because the program requires strict adherence, it may not be the best for someone not nutritionally advanced. It’s also recommended to exhaust other basic diet methods before trying carb cycling.

It may be a good idea to contact a licensed nutrition expert or registered dietitian familiar with carb cycling to see if this type of diet approach is right for you.

Can I Lose Weight?

Carb cycling may be an effective way to lose weight.

There is an important and significant link between carbohydrate intake and blood-insulin levels, says Maloney. When insulin concentrations in the blood remain at a high level, this can lead to increased fat gain. This can hinder weight loss and body composition progress.

Reducing carbs along with creating a caloric deficit is shown to improve insulin sensitivity. Manipulating carbs this way appears to maintain better insulin levels, promotes weight loss, and improves your health.  

As with any weight loss strategy, you get what you put into it. Cycling your intake of carbohydrates is a great way to lose weight and body fat as long as the strategy is followed appropriately, according to Maloney.

Muscle Growth and Athletic Performance

Carb cycling is a popular nutrition strategy for bodybuilders and athletes. Physique athletes especially depend on low or no carb days during the cutting phase of competition preparation. They also create a surplus of energy with carbs to promote muscle gain.

Manipulating carbs enables athletes to eat the right amount of carbohydrates to optimize muscle gain over fat gain. It requires strict adherence to daily menu plans based on energy expenditure during the week. Carb cycling also adheres to the specific consumption of protein, carbs, and fats for every meal.

Protein intake should be higher for muscle growth when carb cycling, says Maloney. Protein should make up 30–35 percent of your daily caloric intake, which in turn can lead to muscle growth.

Carbohydrates during a low phase would account for 10–15 percent of intake and should consist mainly of fresh vegetables, suggests Maloney.

Higher carb days are used during intense training days to supply energy, help with muscle recovery, and provide essential nutrients.  

Health Benefits

Although further research is needed, there appears to be a positive benefit to carb cycling. Some health benefits include:

  • Promotes weight loss: Low carb phase diets typically create a caloric deficit leading to weight loss.
  • Improves fat burning: Low carb days are said to shift the body to use fat for fuel during exercise.
  • Muscle recovery: High carb days refuel muscle glycogen and supply essential nutrients to the body.
  • Improved energy: High carb days are shown to supply energy for demanding workouts.
  • Regulates insulin: Low carb days keep blood sugar spikes low and promotes weight loss. High carb days provide enough sugar in the blood to preserve muscle tissue.
  • Boosts metabolism: Alternating low and high carb intake is shown to increase metabolic function.
  • Regulates hormones: High carb refeed days are shown to improve leptin hormone, thyroid, and testosterone.
  • Psychological wellbeing: Alternating low carb days with a high carb refeed feels less restrictive for an individual for better diet sustainability.  

Pros and Cons

There is no such thing as a perfect diet method and all diets come with positives and negatives. What works for one person may not be the best fit for another. 

Carb cycling appears to have the potential to improve your diet and health. You may even be considering this diet strategy. 

According to Maloney, there are a few pros and cons to consider:

Pros

  • Results are typical

  • Cycles can be pretty short which leads to success

  • Typically leads to better food choices overall

Cons

  • Strict planning and high adherence is necessary

A Word From Verywell

Carb cycling is a new dietary approach that may help with weight loss, muscle development, and health improvement. It requires strict adherence to low and high carb intake days and is recommended as a short-term nutrition strategy. Manipulating carbs may be a better option than diets eliminating this essential macronutrient altogether. Due to carb cycling needing strict planning, it’s advised to exhaust other basic diet methods before trying it. Consulting with a registered dietitian or nutrition expert about carb cycling may also be a great idea to help decide if it’s right for you. 

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Article Sources
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  • Hearris MA et al. Regulation of Muscle Glycogen Metabolism during Exercise: Implications for Endurance Performance and Training Adaptations. Journal of Nutrients, 2018. DOI: 10.3390/nu10030298.

  • Hulston CJ et al. Training with low muscle glycogen enhances fat metabolism in well-trained cyclists. Medicine and Science in Sports and Exercise, 2010. DOI: 10.1249/MSS.0b013e3181dd5070.

  • Impey SG, Hearris MA, Hammond KM, et al. Fuel for the Work Required: A Theoretical Framework for Carbohydrate Periodization and the Glycogen Threshold Hypothesis. Journal of Sports Medicine, 2018. DOI: 10.1007/s40279-018-0867-7.

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