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Carbohydrate Cycling For Weight Loss

It’s a fine line, but there is a way to tweak your carbohydrate intake as a runner for the purpose of losing weight.

While tricky, it’s possible to achieve that delicate balance between weight loss and optimal performance.

Losing or maintaining weight is usually a goal that ranks pretty high on a runner’s priority list. Whether it is for optimal performance, general health, or even the reason they started running in the first place, weight is a critical issue for runners. Unfortunately, despite how close the relationship may seem, losing weight and running at your best aren’t easy to do in conjunction.

If you understand the basic principles of weight loss, you recognize that the most critical factor in weight loss is incurring a calorie deficit. To do so, not only do you have to measure portion sizes, but you have to control the quality of the foods you consume; specifically, limiting your intake of simple carbohydrates. This is why low-carb diets are effective.

However, on the opposite spectrum, to train hard and recover quickly from difficult workouts, a runner must consume adequate calories and fuel with complex carbohydrates — and even simple carbohydrates at the right times. Being in a constant caloric deficit and not providing the muscles with the right type of fuel will leave you tired, struggling to recover, and will derail your performances.

So, what’s the solution if you’re a runner who wants to balance hard training and solid race performances with losing weight? Perhaps we can look again to bodybuilders for an answer. By modifying the time-tested bodybuilding strategy of carb-cycling to the specific metabolic and training demands of runners, it’s possible to achieve that delicate balance between weight loss and optimal performance.

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What Is Carb Cycling?

Simply speaking, carb cycling is a process of alternating between lower-carbohydrate, lower-calorie days and higher-carbohydrate, higher-calorie days. These cycles are usually a couple of days long and are usually based on the days in which you train. Bodybuilders will often use severe carbohydrate and calorie restrictions on their “non-carb” days and load up on their “high-carb” days.

Unfortunately, these extremes won’t be quite as effective for runners because the energy systems required for optimal training are different between bodybuilders and runners. However, we can modify the process to get the benefits we need as runners. First we need to understand the basics of how carb cycling works.

How Carb Cycling Works
To better understand why carb cycling works, it’s important that you understand the role carbohydrates, or lack thereof, play in weight loss.

Mainly, we know that limiting carbohydrate intake lowers insulin levels. Research shows that having low insulin levels accelerates the release of fatty acids and increases fat burning, even during exercise (which is where the idea of running before eating breakfast to burn fat comes from). Considering this information about the role of carbohydrates and insulin, if a runner wants to burn fat and lose weight, he or she would refrain from eating carbohydrates all together.

But we also have to take into consideration the idea of recovery and fuel for optimal performance. Insulin is a very important hormone in the metabolic energy and recovery process. Insulin facilitates the transport of glucose from the blood into the muscle cells, where it can be metabolized to produce energy. Meanwhile, carbohydrates and insulin also stimulate the recovery process by driving critical nutrients, including protein, to damaged muscles. Therefore, it is critical that athletes include carbohydrates in their diet; specifically, before and after workouts, which are the most critical time windows for running performance and recovery.

Carb cycling, when done correctly, facilitates this objective by ensuring that the liver or muscle tissue rapidly absorbs any ingested carbohydrates to replenish glycogen stores. If ingested carbohydrates replenish glycogen stores, there won’t be an excess that ends up in fat cells where enzymes convert glucose into fat for storage, thus allowing you to lose weight.

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The Effectiveness Of Carb Cycling

Recent research conducted by the Genesis Prevention Center revealed that intermittent, low-carbohydrate diets were superior to the standard, daily calorie-restricted diet and the traditional Mediterranean diet in reducing weight, body fat and insulin resistance. In short, mean reduction in weight and body fat was roughly 4 kilograms (about 9 pounds) with the intermittent approaches compared with 2.4 kilograms (about 5 pounds) with the standard dietary approach. The researchers also found that insulin resistance was reduced by 22 percent with the restricted low-carbohydrate diet compared to 4 percent with the standard Mediterranean diet.

Modifying Carb Cycling For Runners

The issue with traditional carb cycling is that it’s pretty extreme and often difficult to follow. Unlike weightlifters, runners usually train 5-6 days per week. Moreover, weightlifters mostly rely on short, alactic bursts of energy while runners require a fairly constant supply of glycogen. Therefore, a runner can’t severely restrict their calorie and carbohydrate intake without suffering mightily on their runs, which will also bleed into subsequent workouts.

Instead, runners can break down the carb cycle process to better coincide with the continued energy demands of distance running. Rather than approach carb cycling with the all-or-nothing tactic weightlifters implement, runners can employ a carb-cycling methodology that utilizes no-carb, low-carb, and high-carb days that correspond with specific training days. Maintaining this type of carb-cycle approach will enable a runner to specifically target days when carbohydrates and calories are needed for performance and recovery while still allowing for the calorie and carbohydrate deficit needed to lose weight.

How To Implement Carb Cycling

No-Carbohydrate, Low-Calorie Days
These will be the rest or cross-training days in your training schedule. If you run more than five days per week, substitute your easiest run of the week for the off day. You’ll want to target a caloric deficit of about 400 to 600 calories on your low-carbohydrate day.

The no-carbohydrate phase should break down to: 1.2 grams of protein per pound of bodyweight, 0.4 grams of fat per pound, and 0.5 grams of carbohydrates per pound. For a 130-pound woman, here is what those numbers would look like:

Protein: 130lb x 1.2 = 156g protein = 624 calories (46% of caloric intake)

Fat: 130lb x 0.4 = 52g fat = 468 calories (34 % caloric intake)

Carbohydrate: 130lb x 0.5 = 65g carbs = 260 calories (19% caloric intake)

Given that an average 130-pound woman burns about 1,900 calories per day, this breakdown would result in a 550-calorie deficit, which will help promote weight loss.

Low-Carbohydrate, Moderate-Calorie Days
Low-carbohydrate days fall on your average training day and are the main driver of carb cycling for running. These days allow you to maintain the energy reserves to run well while giving your muscles fuel for recovery. Low-carbohydrate days should be 3-4 days per week that are standard running days — not your hardest workouts or long runs.

The low-carbohydrate phase should break down to: 1.3 grams of protein per pound, 0.5 grams of fat per pound, and 1.0 grams of carbohydrates per pound. Using the example of the 130-pound woman from before, here is what the numbers would look like:

Protein: 130lb x 1.3 = 169g protein = 676 calories (38% of caloric intake)

Fat: 130lb x 0.5 = 65g fat = 585 calories (33 % caloric intake)

Carbohydrate: 130lb x 1.0 = 130g carbs = 520 calories (23% caloric intake)

While still relatively low in carbohydrates, this breakdown results in roughly the same number of calories burned as calories consumed, which will help fuel you properly for running without putting on weight.

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High-Carbohydrate, High-Calorie days
High-carbohydrate days will coincide with your hardest workout days and long runs. Typically, you’ll have two or three of these per week, depending on the intensity of your schedule. The additional calories and carbohydrates should come from complex carbohydrates and be eaten before and after your runs for optimal fueling. The purpose is to replenish the body’s glycogen stores, stimulate an anabolic response through insulin release, and give the mind a break from the moderately restrictive normal phase of the diet. The general idea is to continue to eat a lot of veggies and add to that fruit and naturally unprocessed carbohydrates, and if necessary, a small amount of processed carbohydrates.

The high-carbohydrate phase should break down to: 1.7 grams of protein per pound, 0.5 grams of fat per pound, and 1.0 grams of carbohydrates per pound. For the same 130-pound woman, here is what the numbers would look like:

Protein: 130lb x 1.7 = 221g protein = 884 calories

Fat: 130lb x 0.4 = 52g fat = 468 calories

Carbohydrate: 130lb x 2.5 = 325g carbs = 1300 calories

If you’re struggling to lose weight while maintaining a rigorous training schedule, give carb cycling a try. Like anything with running, it’s not easy and it requires work and planning, but the results will speak for themselves.