The Benefits of Carb Cycling

March 25, 2019/by Dr. B.J. Hardick

You’ve hit a wall. You consistently lost weight, but suddenly plateaued. Or maybe you’ve become increasingly fatigued after a strenuous workout. Perhaps you’re not building the amount of muscle you want, even though you lift heavy four times a week.

Mixing up your diet could help you break through those obstacles and optimize your results. But should you dial down your carb intake or eat more healthy carbs? The answer — to get lean, optimize athletic performance, and maintain amazing overall health — might be both. And that’s where carb cycling comes in.

What is carb cycling? This approach to nutrition means you alternate carb intake based on your goals. You eat more carbs when doing so might benefit you (such as workout days), and reduce carb intake when your body doesn’t need as many. “Carb cycling is a nutrition strategy in which you alter the amount of carbohydrates you eat on a daily, weekly or monthly basis to maximize sports performance and to build muscle and lose fat and weight,” says Christy Brissette in the Washington Post.

Why Consider Carb Cycling?

Consistency is key for losing weight and improving athletic performance. Maybe you lost weight eating salads for lunch every day or built muscle with lots of lean chicken breast and protein powder.

Carb cycling challenges that approach by mixing things up. “Carb cycling is an advanced diet strategy requiring more manipulation and programming than a typical diet,” says Rudy Mawer, MSc, CISSN. In other words, you have to track your food intake. You might have to do some math. Carb cycling typically requires some trial and error. All of that that requires work, which might (at least initially) feel confusing and, well, inconsistent. So why bother? Among the purported benefits of carb cycling — alternating higher-carb with lower-carb days — include:

  • Raising metabolism
  • Increasing levels of your hunger-suppressing hormone leptin
  • Boosting athletic performance and recovery
  • Sparing protein that your body can use as muscle growth rather than for fuel
  • Optimizing other hormones including testosterone and your thyroid hormones

Carb cycling can also reduce the physiological stress sometimes associated with low-carb diets. Anyone who’s stuck with a low-carb diet long enough knows eating omelettes, bun-less cheeseburgers, and even bacon can become monotonous and boring.

A wider variety of healthy carbohydrates (on higher-carb days), on the other hand, gives your diet more variety and nutrients. Bigger picture, carb cycling can also make sticking to your plan easier and more sustainable, whether your goals include weight loss or building muscle.

Healthy Eating & Carbs: Why Eat Carbs?

As high-protein and more recently, ketogenic (or high-fat) diets have become more popular, carbohydrates have developed a bad reputation. But not all carbs should be demonized — carbs can be part of a healthy diet. Sure, low-carb diets cut out refined sugars, fake foods, and high-glycemic carbs, but they also cut out dietary fibre, energy, and micronutrients.

What’s more, numerous studies over the past 40 – 50 years show carbohydrates are the primary macronutrient to sustain and improve physical performance. Even as new trends appear (including a high-fat ketogenic diet), carbs are still beneficial for certain athletes’ diets. “Although dietary protein and fat can provide necessary energy to perform physical activity, carbohydrate is the substrate most efficiently metabolized by the body and the only macronutrient that can be broken down rapidly enough to provide energy during periods of high-intensity exercise when fast-twitch muscle fibers are primarily relied upon,” says Mitch Kanter, Ph.D.

How Carbs Impact Glycogen

When your body breaks down carbohydrates to glucose, insulin delivers that glucose from your bloodstream to cells for energy. But those cells aren’t greedy. They take whatever glucose they need, but nothing more. Insulin still has to deliver that excess glucose somewhere. It can’t just hang out in your bloodstream.

Fortunately, your body has a backup source of fuel: your liver and muscles store excess glucose as glycogen that your body uses as fuel between meals. In other words, glycogen is a readily mobilized storage form of glucose or energy that helps maintain blood glucose levels. When your body needs glucose for energy (like, during a strenuous workout), it can break down that glycogen from your liver stores.  

Glycogen is the main energy substrate during high-intensity exercise, and depleted glycogen stores can lead to fatigue and other issues. That’s why many athletes refuel with carbohydrates after exercise, when glycogen synthesis increases to fill those depleted glycogen stores.

Sufficient carbohydrates, then, provide your muscles with the energy to maintain performance around your workout. After you exercise, eating carbohydrates can replenish those depleted glycogen stores, sort of like putting gasoline in your car when it runs nearly empty.

Nutritious, carbohydrate-rich foods are your best bet to replenish glycogen stores. Eating these nutrient-dense carbs is like refuelling your gas tank after a long drive. They help sustain steady, consistent energy. Likewise, higher-carb days can break your dietary monotony, keep your metabolism on its toes, and perhaps help you break the dreaded plateau many dieters experience.

But what about non-workout days when you don’t necessarily have the high energy demands for glycogen? That’s where carb cycling comes in. On those days, you eat fewer carbohydrates so your body shifts into fat-burning mode. You get the best of both worlds with carb cycling: higher-carb day help replenish those glycogen stores, while lower-carb days shift lower insulin levels so your body can access fat for fuel.

Giving Carb Cycling a Try: How to Carb Cycle

Carb cycling helps optimize muscle glycogen, which can optimize performance and prevent muscle breakdown. It can also help you lose weight when your metabolism adjusts to your normal way of eating and you hit a plateau.

There’s no perfect formula for carb cycling. One approach is to get about half your caloric intake from carbs on high-carb days and about a quarter of calories from carbs on low-carb diets. While your protein intake will remain consistent, your dietary fat intake will increase (during low-carb days) or decrease (during higher-carb days). This should happen naturally, but tracking can give you a better idea of macronutrient intake.

If that sounds confusing or you just don’t want to do the math, try this approach:

  • On lower-carb days, focus on plenty of leafy and cruciferous vegetables, nuts, seeds, and low-sugar fruits such as berries and avocado. Shift your ratio to more protein and healthy fats.
  • On higher-carb days, incorporate more carbohydrates including fruit and starchy foods like quinoa or sweet potatoes. The emphasis here should be on the most nutrient-dense carbohydrates.

In other words, don’t over-think carb cycling, stress out about eating too many or few carbs, or make it more complicated than it needs to be.

5 Ways to Optimize Carb Cycling

Whether you want to step up your physical performance or nudge the scales in your favour, carb cycling might be the strategy that helps you reach your goals. Everyone is different, and determining your ideal carb ratio might feel hit-or-miss in the beginning. These five strategies can help you incorporate carb cycling intelligently:

  1. Keep a food journal. Writing down everything you eat can help you find the right ratio of carbs that benefit you and maintain a healthy diet. How you track depends on how vigilant you want to be. If numbers help, you can find phone apps that tally up your macronutrient intake. Or you can just write down what and when you ate. (Bonus of food journals: one study showed people who tracked what they ate lost twice the weight of those who didn’t.)
  2. Higher-carb days don’t mean pigout days. Increasing your carbs healthily does not mean gorging on pizza and ice cream. Focus on quality carbs in your healthy meals. “Be careful not to overdo it on the higher-carb days,” says Brissette. “The difference between your lower-carb and higher-carb days could be narrower than you expect. Higher-carb days aren’t a ‘cheat day,’ so don’t think this diet is your license to go to an all-you-can-eat pasta bar.”
  3. Replenishing glycogen stores post-workout doesn’t require that many carbohydrates. On higher-carb days, you don’t need to eat massive amounts of carbohydrates to get results. You can replenish glycogen stores with about 150 calories of carbohydrates (for a 160-lb athlete) every 30 minutes for two to four hours (or until your next meal). That’s only about one medium potato, a cup of pasta, or a cup of white rice.
  4. “Lower-carb” does not mean “no carb.” Just like higher-carb days aren’t permission to gorge on sugary foods, low-carb days don’t mean meat, cheese, and other no-carb foods. On the days your body requires fewer carbohydrates, you still need some, including leafy and cruciferous vegetables. Otherwise, you’re missing out on important nutrients including fibre that only carbohydrates can provide.
  5. Be flexible and experiment intelligently. Stressing out about caloric intake or how many carbohydrates you eat isn’t the point of carb cycling. In fact, it can be counterproductive. Keep an open mind, tweak your plan as necessary, pay attention to how you feel, and see this as a fun experiment that allows more variety in your diet and could become the needle mover to achieve your goals.

Carb cycling might not be ideal for your goals. After all, no plan works for everyone. But if you’ve hit a weight loss plateau or find you’re stalling at the gym, this might be an ideal formula to reach a new level of performance or get the needle moving again on the scales.