Should You Take a Ride on the Carb Cycling Rollercoaster?

By , Becky Hand, R.D.
It feels as though there is no escaping carbohydrates when it comes to talking about healthy eating. The latest carbohydrate-focused diet to take center stage combines very low carbohydrate days along with days packed with carb-containing foods. Known as "carb cycling," the premise of this eating plan comes from the world of bodybuilders and professional athletes looking to quickly increase muscle mass—though that hasn't stopped the average person looking for a weight-loss solution to jump on the bandwagon as of late. But does this eating plan really "optimize" carbs to boost weight loss?

What is Carb Cycling?

While carb cycling involves alternating between high carbohydrate intake days and low carbohydrate intake days at its core, there are many versions of the plan. Some people adjust their carb intake day-to-day, usually based on their exercise and competition schedule, while others do longer cycling periods by week or month. Some plans use the high-low carb routine for six straight days with a reward or cheat day on the seventh.
Search the internet and you may come across claims of plateau-busting, metabolism-boosting and fat-burning benefits when using a carb-cycling plan, but in fact, only one small, short-term study regarding carb cycling and weight loss exists at this moment in time. Published in 2013 in the "British Journal of Nutrition," this three-month study resulted in improved insulin sensitivity and a slightly greater weight loss (about 2.75 pounds) in overweight women who consumed fewer carbohydrates (less than 40 grams) two days a week, compared to the control group who used a more traditional weight loss diet. Both groups ate the same number of total calories weekly. While promising, more research is needed for recommendation guidelines.

Carb Cycling by the Numbers

Without solid research evidence on carb cycling, it is possible to find many versions of the eating plan and proponents use differing guidelines. The chart below shows just one example of a day-to-day carb-cycling plan based on days with and without exercise. Exact calorie and carb amounts would be determined by one's gender, weight, muscle mass, activity level, exercise plan and ultimate goals.
As you can see by the numbers, a carb-cycling plan results in weight loss when you maintain a calorie deficit, which is no weight-loss secret. Food choices, carb sources and portion sizing are still keys to ultimately finding success. When selecting your carb servings, it is important to opt for smart-carbs that are also nutrient-rich, while carbohydrates that contain little or no nutritional value, such as refined-grain products or over-processed foods.
  Female Male
Very Low-Carb Day
Non-Exercise or
Light Activity Day

(up to 25% of calories)
  • Grams
  • Servings


40 -75
2 ½ - 5

50 - 95
3 ½ - 6 ½
High-Carb Day
Exercise or
Vigorous Activity Day

(45-65% of calories)
  • Grams
  • Servings

170 - 245
11 ½ – 16 ½

200 - 295
13 ½ - 19 ½
For some who struggle with eating plans that cut out whole food groups, the carb-cycling plan can be liberating and easier to maintain than other very restricting or very low-carbohydrate eating plans. Others find the cycling approach to be too complicated and time-consuming.
While a carb-cycling plan is safe for most people, do not start using a carb-cycling plan before checking with your primary care provider or registered dietitian. This is especially important if you have a medical history of diabetes, heart disease, metabolic syndrome, hypoglycemia, disordered eating or binge eating. Do not use this type of eating plan if you are pregnant or breastfeeding. Avoid carb-cycling plans that require or force the purchase of added supplements, shakes or beverages. 
The bottom line is this: Diets that cut calories usually results in weight loss and so will carb cycling. If you find that controlling carb intake is an area of struggle in your weight-loss plan, carb cycling may offer the increased flexibility you desire, but with added structure and accountability you need to make a real change. If you decide to take a ride on this rollercoaster, be sure to reach for quality carbs on both your feast and famine days.