It’s a short-term pattern that people often follow while training called carb cycling. The goal: eating more of the macro when you need it most, like on days when you have a long run or intense lifting session planned, and less of it on days when the physical demand is lower. “The point and purpose is to match your intake with your output,” says Brian St. Pierre, RD, CSCS, director of performance nutrition at Precision Nutrition. “Protein and fat needs are generally more static, but carb needs vary depending on activity levels.” Eating enough complex carbs at the right times signals your body to create beneficial hormones such as leptin, which helps you maintain your ideal weight, Pinckney says. It also prevents spikes in insulin and provides energy. Specific plans vary depending on your goals, but a typical week of carb cycling might include three low-carb days, two high-carb days, and two moderate-carb days. But the process is precise. Here are the biggest mistakes people make when carb cycling, and the much-needed fixes.
Carb cycling is something of a misnomer—it’s not just about carbs. Sometimes, people reduce their carb intake on low-activity days but eat more fat and protein on those days, so much that they’re getting the same number of calories overall. If that happens, “you’re not going to see much fat loss in the long run,” St. Pierre says. When carbs fluctuate, your total calorie intake should, too.
Cycle fix: Find your maintenance calories, the number that keeps you at your current weight, with an online calculator. On easy days, get 10 to 20 percent less of your calories from carbs without upping your fat or protein intake, St. Pierre suggests. Keep in mind that there are four calories per gram of carb, so if you eat 2,000 calories per day, reduce your carb intake by 50 grams (roughly 200 calories worth) on days you’re not training heavily.
The 10-to-20-percent rule applies specifically to carbs, but there should never consistently be more than a 33 percent difference in the total number of calories you eat from one day to the next. That type of variance can hurt recovery and make it harder for you to stick to a carb cycling plan, says Zach Moore, CSCS, a Bloomington, Indiana-based nutrition coach at Precision Nutrition.
Cycle fix: Eat at least 68 percent of your typical energy intake on reduced-carb days, Moore says. That means at least 1,360 calories for people who typically eat 2,000 per day.
People often use high-output days as excuses to eat whatever they want, Moore says. That’s a flawed plan, because it’s easy for unhealthy habits to become more regular.
Cycle fix: Indulgences are fine now and then, but your main focus should be on nutrient-dense options, Moore says. Aim for whole foods, like potatoes and oats on high-carb days and eggs and nuts on low-carb days.