As a registered dietitian, I am often asked about carbohydrate cycling. Many people wonder what it is, whether it works, and how to safely do it. It’s a popular approach among athletes, bodybuilders and fitness trainers, but carb cycling can become a confusing concept if you’re new to it.
Here’s what you need to know about carbohydrate cycling: Here are some examples of how it works, why people try it, important considerations before you start, and how a carb cycling plan might look like in real life.
What is carbohydrate cycling?
Carbohydrate cycling is a feeding strategy that alternates carbohydrate intake on various days, usually cycles between high, medium and low carbohydrates.
The idea is to spend time making your carbohydrate intake suit your body’s energy needs. For example, on days when you are experiencing intense training, you may eat less carbohydrates and more carbohydrates on days when you are resting or doing light activities.
Instead of tracking fixed carbohydrate intakes every day, carbohydrate cycling creates a fluctuating or “wave-like” pattern in carbohydrate consumption over a week.
The concept may sound trendy, but the principles behind it are simple. Your body uses carbohydrates for energy, especially during moderate to high intensity exercise. It aims to optimize performance and potentially affect body composition by eating more carbohydrates when you need fuel and reducing carbohydrates when you don’t.
Why do people go through the carbohydrate cycle?
People try carb cycling for a variety of reasons. Here are the most common:
1. Supporting athletic performance
Athletes and physically active individuals can use carbohydrate cycling to ensure that glycogen storage (a type of muscle and liver carbohydrate storage) is replenished for demanding training. Having enough glycogen can improve your endurance, strength and recovery.
2. Body composition goals
Some people use carbohydrate cycling along with strength training and fat loss programs. High carb days can support intense training and recovery, so this strategy can help you maintain muscle mass during a calorie deficit, while low carb days can help reduce your overall calories and carb intake.
3. Break through the weight loss plateau
Research on this is still emerging, but some have found that various carbohydrate intakes can help prevent slower metabolism that can occur in a consistent low-calorie or low-carbohydrate diet.
4. Management of hormone responses
Carbohydrate intake affects hormones such as insulin and leptin, which play a role in appetite regulation and metabolism. Carbohydrate cycling may help regulate these hormones, but further research is needed to confirm the long-term benefits.
Important considerations before trying carb cycling
Before you jump in, there are a few important points to keep in mind.
1. Carbohydrate quality is important
Carbohydrate cycling is not just about quantity. Carbohydrate quality is equally important. Choose nutritious, high-fiber carbohydrates such as fruits, vegetables, legumes, and whole grains. Even on high carb days, avoid resorting to refined carbs and sugar.
2. Protein and fat are still essential
Carbohydrates have attracted most attention in carbohydrate cycling, but protein and healthy fats are important every day for your fullness, muscle maintenance and overall health.
3. It’s not for everyone
People with certain medical conditions such as diabetes, hypoglycemia, or those with a history of eating disorders may not be good candidates to follow a carbohydrate cycling plan. It can also be taxed mentally and emotionally for some people because intake needs to be tracked and adjusted regularly.
4. Energy needs should guide you
Carbohydrate needs depend on your activity level, body size and goals. For example, training an endurance runner for a marathon may require more frequent high carb days than someone lifting weights three times a week.
5. Hydration is important
Carbohydrates are stored in the body along with water, so shifting carbohydrate intake can affect your hydration level. Pay attention to the balance between liquid intake and electrolytes, especially on low carb days.
Is there science behind carb cycling?
Carbohydrate cycling theory is rooted in sports nutrition principles, but research on carbohydrate cycling as a long-term diet approach is limited.
But we know that:
High carbohydrate availability improves endurance and high-intensity exercise performance. Low carbohydrate periods can increase fat oxidation (fat burning) during exercise. Strategic manipulation of carbohydrates can affect glycogen storage, hormonal response, and recovery.
In any case, whether cycling carbohydrates offer a significant advantage in weight loss or body composition, it is still debatable to tailor carbohydrates to your daily needs.
What does carbohydrate cycling look like in real life?
Carbohydrate cycling can be configured in a variety of ways depending on your goals, lifestyle and preferences. Below are some general approaches:
Example 1: High carbs on training days
High Carbohydrate Days (Week/Week): Used on intense training days such as heavy lifting and high intensity interval training (HIIT). Medium Carbohydrate Days (2-3 days a week): Used on medium workout days or when active but not pressing strength. Think about it – Pilates, jogging, etc. Low carb days (1-2 days a week): Used on days or days when you have light activities such as yoga classes or going out for walks.
Sample weekly schedule:
Monday: High Carb (Leg Day) Tuesday: Medium Carb (Upper Body Training) Wednesday: Low Carb (Break Day)
Thursday: High Carbs (HIIT Training) Friday: Medium Carbs (Yoga + Lightweight) Saturday: High Carbs (Long Run) Sunday: Low Carbs (Break Day)
Example 2: Event-based carbohydrate cycling
Athletes may increase carbohydrates for several days before competition or long-term races to maximize glycogen storage (the practice known as carbohydrate load). The rest of the time their carbohydrate intake may be milder.
Race Week Sample Pattern:
Mon – Wed: Medium Carb Training Day Thu – FRI: High Carb Loading Day before the Race: Race Day (High Kalb Breakfast) Sun: Low Carb Recovery Day
Example 3: Calories deficiency caused by carbohydrate cycling
Some people use carbohydrate cycling during the fat loss stage to help them maintain their performance in the gym. This might look like this:
High Carbohydrate Day: Supports intense training and helps maintain low muscle mass carbohydrate days: reduces overall calorie intake and promotes fat utilization
Sample Intake Target:
Large Carbohydrate Day: ~50-60% of calories from carbohydrate Day: ~35-45% of calories from carbohydrate Age: 15-25% of calories from carbohydrate
Carbohydrate Cycling Conclusion
Carbohydrate cycling can be an effective and flexible tool when done intentionally and balanced. It can work best for people who are training for different training intensities throughout the week, for those who are training for specific events (i.e. running a marathon), or for those who enjoy structured dietary patterns and don’t mind tracking carbohydrate intake. In contrast, it may not be suitable for people with a history of eating disorders, certain medical conditions, or may have a relatively stable, moderate level of activity.
If you are interested in trying it, I recommend working with a registered nutritionist to determine your optimal range of carbohydrates and avoid unnecessary restrictions.
