In carb cycling, your week is divided among three types of days: no carb days, low-carb days and high-carb days.
NO CARB DAYS: On these, you eat high-fiber vegetables such as leafy greens, asparagus, broccoli, onions, peppers and mushrooms freely, along with lean protein and a serving or two of good fats. Refrain from starchy carbs such as potatoes, rice, cereals and oats. These include starchier veggies such as beans, zucchini, squash, and pumpkin. Total carb intake should be less than 25 grams per day – all from fibrous veggies.
LOW CARB DAYS: Here, the goal is to stay below 75 grams of carbs. Once again, fibrous veggies can be eaten freely, but add in two to three servings of starch from clean sources such as brown rice, sweet potatoes, oats, starchy veggies and fruit. “Clean” carbs are hypoallergenic ones — free of gluten, soy and dairy. For best results, having starchy carbs post-workout on these days is recommended.
HIGH CARB DAYS: The total amount of carbs will vary based on your size and activity level. Women will consume between 150 and 200 grams while men can get away with up to 300 grams. Most of these should come from clean sources. But if you are going to enjoy a cheat meal, it is advantageous to have it on a high-carb day.
Don’t forget to continue to eat plenty of lean protein and a serving or two of healthy fats. A high-carb day is not an excuse to binge eat; it’s a systematic way to reset muscle-building and fat-burning hormones.
Using these three daily eating protocols, it’s possible to alter the body’s hormonal environment to maximize fat loss and muscle gain throughout the week.
A sample week of carb cycling looks like this:
Day 1: No carb
Day 2: Low carb
Day 3: High carb
Day 4: No carb
Day 5: No carb
Day 6: Low carb
Day 7: High carb
Since carb cycling employs high carb days, it’s psychologically satisfying, curbing cravings and making it easier to adhere to the program. But when we do two or more higher carb days in a row, fat storage momentum can build. That’s why no-carb days follow high-carb days — it minimizes the potential for fat storage and keeps your body insulin-sensitive.
Insulin? What does that have to do with anything? , you might be asking. As it turns out, quite a bit.
Why Carb Cycling Works
Cycling carbs is more of a hormonal strategy than a caloric one. Varying carb intake influences several hormones that determine body composition. For starters…
Insulin: The fat-storing and muscle-building hormone
When we consume carbs, insulin is released into the bloodstream to help the metabolic machinery shuffle carbs into the liver for use as fuel later, or to muscle cells for storage. These storage depots for carbs are finite.
When they become full, as they do when we eat too many carbs, they are metabolized and stored as fat.
The key to carb consumption, as far as insulin is concerned, is to eat to the point of satiety and having enough fuel for workouts and energy balance, but not consuming so much that we get spillover into fat storage.
Insulin release varies based on type and amount of carb consumed. Carb cycling manipulates insulin to minimize fat storage and maximize muscle synthesis. Low-carb and no-carb days help us stay sensitive to insulin, and push fat burning. High-carb days maximize muscle growth and replenish carb storage to enhance exercise intensity.
Leptin: A hunger hormone
Produced mostly by the fat cells, leptin is a regulatory hormone for hunger and satiety. It is released in response to “refeeding,” defined as a time of 12 to 24 hours of increased carbohydrate and caloric intake.
Unlike insulin, leptin does not increase significantly as a result of a single meal. Instead, it creeps over a sustained period of increased carbohydrate consumption. Leptin acts as a feedback mechanism in the hypothalamus to signal satiety. In addition, through secondary hormones, leptin also signals to the body to speed metabolism.
In those who eat a high-carbohydrate, high-calorie diet, leptin remains high. This can result in leptin resistance, where the hypothalamus is no longer able to “hear” leptin. When this happens, we cannot feel full — a dangerous outcome for those trying to lose weight.
However, very low levels of leptin, which occur on a low calorie and low carbohydrate diet, give the body the opposite message: be hungry, eat, conserve, slow down.
In carb cycling, when leptin begins to recede to the point of drastically increasing hunger and slowing the metabolism, a high-carb day is in place to help reset it. This way, we stay leptin-sensitive.
Serotonin: The sanity hormone
A “feel good” brain chemical, serotonin, boosts mood and is often used in pharmaceuticals to treat depression. Carbs boost serotonin production, so eating carbs boosts mood.
Low serotonin, as would occur as a result of a low-carb diet, is associated with increased cravings for sugar and chocolate. Many diets fail because low serotonin makes dieters feel depressed. Carb cycling regulates serotonin levels and as a result, curbs cravings. From a psychological perspective, carb cycling as a protocol is easier to sustain than other diets because serotonin never drops off completely.
Cortisol: A catabolic hormone
Cortisol is a catabolic hormone, meaning it breaks down molecules to be used as fuel. It can be both beneficial and detrimental, as it doesn’t discriminate between breaking down muscle and fat for fuel. However, there is plenty of research to show that eating protein can help maintain muscle even in a catabolic state.
Eating a meal containing carbohydrates essentially shuts off cortisol production; this is why many bodybuilders will eat a meal containing carbs and protein immediately upon waking. By carb cycling, excess cortisol production (and muscle catabolism) is avoided. At just about the time that cortisol production begins to become excessively catabolic following no- and low-carb days, a high-carb day is in place to reset this hormone to avoid muscle loss.