As the name suggests, carb cycling involves varying your intake of carbohydrates. The cycle itself varies — it’s often daily, with people switching between high- and low-carb days, but it can also be weekly or monthly.
For example, on a five-day carb cycling program, a person might eat around 100 to 125 grams of carbohydrates for three consecutive low-carb days, then consume 175 to 275 grams for two high-carb days, when they’re more physically active.
For perspective, the FDA recommends that someone on a 2,000 calorie diet should consume about 300 grams of carbohydrates daily.
Carb cycling is based on research that links carb intake with athletic performance and muscle recovery. A 2010 study in the Journal of Sports Medicine found that the timing and amount of carbohydrates a person eats affects how their body breaks down carbs into glycogen, a key source of energy in the body.
Since more intense physical activity depletes glycogen faster, some research suggests that carb intake goals should be adjusted daily, based on the intensity of that day’s workout.
That’s why you may want to eat more carbs around periods of physical activity. But many factors influence those results, including the type of workout, a food’s glycemic index, nutrition composition, and quantity.