Carb cycling is a regimen for elite athletes who want more control over their weight and energy optimization. It involves eating complex carbs to ensure that energy levels do not dip too low and cause poor performance. It has been compared to the ketogenic diet and, like that popular low-carb, high-fat eating method, has become a trendy workout topic. But, the science behind carb cycling is still in question and is a source of controversy.

Carb Cycling Basics

Carb cycling is an experimentation-based regimen that causes major changes to your body, so it's a good idea to check with a health professional before trying it. While there are a variety of methods, most people start with an objective, then create a schedule around those goals, which includes keeping a detailed food diary. Though discipline is required, remain flexible, as you may need to alter your consumption to deal with your training schedule, output, and recovery.

Food-diary experimentation training-schedule BreatheFitness / Getty Images


Weight Loss

The science behind carb cycling for weight loss involves a less-active, low-carb period where you reduce carbohydrate intake for two to three days. This means your intake is about 0.5 grams per pound. For example, a 150-pound person will consume a maximum of 75 grams and an absolute minimum of 50 grams a day. During these days, the body relies more on stored sugars and fats for fuel, which facilitates weight loss.

Weight-loss low-carb fat-as-fuel mihailomilovanovic / Getty Images


Overall Metabolic Health

When it comes to your metabolic health, there are a couple of overall body benefits of which to be mindful. Carb cycling helps you lower your fasting glucose levels, which improves brain health and reduces the risks of nerve and kidney damage. Weight reduction decreases triglycerides, making cardiovascular risks down the road less likely.

Fasting-blood-sugar metabolic-health courtneyk / Getty Images



During low-carb days, the objective is to achieve ketosis, a metabolic state where the body breaks down fat stores. Refeeding between low-carb days breaks that ketosis process. During that high-carb period, slow-burning carbohydrates make up between 60 and 70 percent of your diet. Proponents of carb cycling believe this resets your metabolism and helps you better maintain weight loss over time.

Refeeding ketosis fcafotodigital / Getty Images


Thyroid Hormone Regulation

Carb cycling regulates other key hormones and functions, including the thyroid. Thyroxine and triiodothyronine hormones must balance at all times. Reducing your carbohydrate intake can increase thyroid hormone sensitivity, which means fewer hormones are needed for optimal regulation and balance, reducing the burden on the thyroid.

Thyroid-hormone hormone-regulation ttsz / Getty Images


Busting Plateaus

If you have been on a restrictive diet, there may come a time when your body will stop responding. Diet plateaus are frustrating. Carb cycling helps your body take advantage of insulin to get you over that stagnation phase. Insulin helps the body metabolize carbohydrates. The idea is that by varying your carb intake, you carefully manipulate the amino acid and glucose entry into your muscles, jolting your metabolism and getting you back on track.

Diet-plateaus insulin MRBIG_PHOTOGRAPHY / Getty Images



For bodybuilders, carb cycling offers multiple benefits. On low-carb days, the decrease of intra-abdominal fat leans them out for their next competition. During high-carb days, increased glucose and fructose support muscle growth by replenishing glycogen stores. A sample breakdown for a five-day cycle is to start at 150 grams of carbs on day one, then decrease by 50 grams through to Day three. From there, increase by 75 grams for the next two days, until you reach the maximum of 200 grams.

Bodybuilders abdominal-fat high-carb skynesher / Getty Images


Endurance Athletes

When it comes to endurance, athletes may find that performing with low glycogen stores results in improved training adaptation. However, low-carb means weak performance during high-intensity training. A study confirmed that endurance training with low carbohydrates limits ATP or adenosine triphosphate, which is responsible for carbohydrate breakdown in the muscles. When high-intensity training sessions were paired with high-carbohydrate availability and low-intensity with low-carb, scientists realized that the key for improved endurance athletic performance was in manipulating the times of carbohydrate intake.

ATP endurance-athletes carbohydrate AMR Image / Getty Images


Who Shouldn't Carb Cycle

Carb cycling is not recommended for women who are pregnant or lactating or those with a history of eating disorders. Individuals with adrenal fatigue need to be careful of blood sugar spikes, as they can exacerbate the condition. Hashimoto's disease, also known as autoimmune thyroiditis, requires a diet composed of between 12 and 15 percent carbohydrates, so individuals with the condition can't execute the refeeding part of the cycle. Finally, professionals caution against carb cycling for those with diabetes or hypoglycemia, as too few carbohydrates affect fluid balance and serum glucose concentrations.

Carb-cycling blood-sugar fluid-balance ogichobanov / Getty Images


Carb Cycling As a Lifestyle

Despite the fact that carb cycling is recommended as a short-term regimen for elite athletic training, like many fads, some people think of it as a fitness trend for everyone. Unfortunately, limiting carbs over a long period puts the body at risk of deficiency in nutrients, such as thiamine, folate, and potassium. Individuals may also experience fatigue, digestive problems, and poor concentration, in addition to lean muscle loss. Researchers are still studying the results of the diet, but for those looking to lose or maintain weight, dieticians recommend sticking to the basics of balanced nutrition and physical activity.

long-term-carb-cycling fatigue muscle-loss M_a_y_a / Getty Images


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