What Is Carb Cycling?
On a carb cycling meal plan, you rotate between high-carbohydrate and low-carbohydrate days. There may even be "no-carb" days.
While there's limited research on it, this diet may help serious athletes and bodybuilders drop weight and gain muscle. They cycle carbs before intense workouts or long-haul exercises, such as marathons. Some people try to kick-start weight loss by carb cycling, even though you mostly lose water weight.
There're many ways to carb cycle, but the general approach is to eat high levels of carbs on days you exercise hard. Your digestive system breaks down carbs into glucose to fuel your body. On high-carb days, you might eat 2-2.5 grams of carbs for every pound of your body weight to fuel your activity.
On low-carb days, you'll eat fewer carbs and be less active. You might eat half a gram of carbs for every pound of body weight. You may even eat less than 30 grams of carbs on "no-carb" days.
Another option is eating about 100-125 grams of carbs daily for three days. Once your body isn't relying so much on carbs for fuel, you'll likely have fewer carb cravings and feel more energetic. For the next two days, you'll increase your exercise intensity and eat 175-275 grams of carbs each day.
How Does Carb Cycling Work?
After you eat carbs, your blood sugar, or glucose, rises. Your pancreas makes a hormone called insulin to take glucose into your cells. There, your cells use glucose for energy or store it as glycogen for later. Glycogen can also be stored as fat. When needed, your pancreas can signal the release of stored glucose. This back-and-forth makes sure your body has the right amount of sugar.
Your body needs carbs, proteins, and fats for energy, measured in calories. One gram of carbs or protein has 4 calories, but a gram of fat gives you 9 calories of energy. To balance your diet, get 45%-65% of your daily calories from carbs, 10%-35% from proteins, and 20%-35% from fats.
It's not well studied, but cycling in high-carb days can build up your glycogen stores. When you exercise hard, you use up your glycogen. Then, on low-carb days, you'll break down fat for fuel when you go for low-intensity workouts.
These short periods of carb cycling can give your body a chance to burn fat instead of carbohydrates. Stick to low-fat meals on high-carb days and add fats back on low-carb ones. Keep your protein intake the same every day. And get plenty of exercise on high-carb days to prevent weight gain.
Benefits of Carb Cycling
Carb cycling helps endurance athletes keep their energy up during hard exercises, such as marathon running. It may help them burn fat, build muscle, and increase endurance. But you're not likely to lose weight if you don't exercise intensely on high-carb days.
Go for unprocessed carbs found in dairy products or plant-based foods like beans, grains, fruits, and vegetables. Focus on these healthy carbs to get vitamins, minerals, and plenty of fiber. Staying away from sugary and refined carbs can help:
- Improve how well your body uses insulin (insulin sensitivity)
- Improve your metabolic health
- Lower your cholesterol, triglycerides (blood fats), and blood sugar
- Burn fat faster during workouts
- Lower your risk for type 2 diabetes and metabolic syndrome
Eating fiber-rich, plant-based carbs such as oatmeal, legumes, or quinoa can help you:
- Lower your cholesterol
- Lower your risk for heart disease, type 2 diabetes, and stroke
- Add dietary minerals, such as iron, calcium, and potassium
- Get daily vitamins, such as folate, the natural form of folic acid
- Get fiber and antioxidants to lower inflammation
- Keep the hormone ghrelin in check to lower your appetite
How to Do Carb Cycling
Carb cycling is a personalized diet strategy. You'll likely change up the meal plan to fit your overall health and exercise goals. Here’s a sample week:
- Day 1 (high-intensity workout): 175-350 grams of carbs
- Day 2 (low-intensity workout): 100-125 grams of carbs
- Day 3 (high-intensity workout): 175-350 grams of carbs
- Day 4 (low-intensity workout): 100-125 grams of carbs
- Day 5 (high-intensity workout): 175-350 grams of carbs
If you'd like to have longer low-carb periods, try to cycle in high-carb re-feed days. Here's a sample plan to try:
- Days 1-5 (low-intensity workouts): 100-125 grams of carbs
- Days 6-7 (high-intensity workouts): 175-350 grams of carbs
Your carb intake can depend on your body size, muscle mass, and metabolism. It's a complex meal plan that takes some fine-tuning. Match your carbs to your exercise type, time, and intensity. This will ensure that you have the energy needed to do those intense workouts.
Always ask your doctor or a registered dietician before starting a new diet like carb cycling to make sure it's right for your health.
Is Carb Cycling Safe?
There aren't many long-term studies on carb cycling, but it’s generally considered safe for short-time use. Balance your diet to keep your blood pressure, blood sugar, and cholesterol under control.
When you cut back on carbs for a few days, you might have:
- Sleep problems
- Tiredness
- Constipation
- Bloating
- Mood issues
It's called the "carb flu," but you're not really sick and it usually doesn’t last long. Drinking water and getting enough electrolytes (important minerals such as calcium, sodium, and potassium) can help.
Carb cycling is extreme, and it isn’t right for everyone. Experts aren't certain, but you may lose muscle mass if you exercise with low glycogen stores. And higher carbs and fiber can irritate your stomach, too.
Eating high- and low-carb meals can cause your blood sugar to rise and fall. Don't try carb cycling if your body is sensitive to these changes or if you:
- Are pregnant or breastfeeding
- Are underweight
- Have a current or previous eating disorder
- Have adrenal issues
- Have insulin resistance or type 2 diabetes
When in doubt, check with a health professional before you start. But any diet that restricts food groups can be hard to keep up and heighten your focus on food. Your doctor or dietician can help you find therapy and nutritional counseling to treat unhealthy relationships with food.
If you can't stop thinking about "healthy" eating, you may have orthorexia. Constantly checking for healthy food and ingredients can restrict your diet. It may also raise your risk for conditions where you lack vitamins or minerals (deficiency).
For others, higher-carb periods can become chronic episodes of binge eating. Get help early if you binge. Treatment helps lower your risk for type 2 diabetes, metabolic syndrome, gastrointestinal problems, and other health conditions.
If you or a loved one have problems thinking about food, contact your doctor right away for treatment.
Carb Cycling Meal Tips
Some carbs are healthier than others, and quality matters. Less healthy carbs include refined grains such as white flour, white rice, and sugars. Lower-quality, processed foods are made with them.
Here are some tips to help you eat the best carbs. On high-carb days, you can:
- Choose high-fiber fruits and vegetables.
- Opt for low-fat milk, cheese, yogurt, and other dairy products.
- Stock up on complex carbs such as legumes, beans, lentils, and peas.
- Have lots of whole grains.
- Limit refined grains, added sugars, and highly processed foods.
On low-carb days, you can focus on:
- Nonstarchy veggies, such as lettuce, spinach, broccoli, or cauliflower
- Lean protein sources, such as fish, chicken, or lower-fat dairy products
- Healthy fats, such as avocados and olive oil
Carb Cycling Meal Plan
You can carb cycle many ways, but here's a sample eating plan.
| Exercise | Fat | Carbs | Carbs Amount (grams) | |
| Monday | High-intensity cardio workout | Low | High | 175-350 |
| Tuesday | Low-intensity workout | High | Low | 100-175 |
| Wednesday | Low-intensity workout | High | Low | 100-175 |
| Thursday | High-intensity cardio workout | Low | High | 175-350 |
| Friday | Low-intensity workout | High | Low | 100-175 |
| Saturday | Rest day | High | Low | Less than 100 |
| Sunday | High-intensity cardio workout | Low | High | 175-350 |
High-carb day meal plan
- Breakfast: Oatmeal with blueberries and Greek yogurt
- Lunch: Whole-wheat turkey wrap with tomatoes
- Dinner: Chicken pesto on whole wheat pasta, and green spinach salad
- Snacks: Whole-grain bagel with low-fat cream cheese, carrots, and almonds
Low-carb or rest day meal plan
- Breakfast: Egg-white and low-fat cheese omelet
- Lunch: Baked rosemary chicken, green beans, and steamed broccoli
- Dinner: Cedar plank salmon, cauliflower risotto, and asparagus
- Snacks: Pumpkin seeds, strawberries, and cheese stick
Takeaways
Carb cycling involves alternating between eating high and low amounts of carbohydrates. Some serious athletes use it to keep their energy up during workouts without gaining weight. There isn't much research on carb cycling. Although generally safe for short periods, carb cycling isn't for everyone. Before trying this extreme diet plan, check to see if it's right for your health.
Carb Cycling FAQs
How do you carb cycle correctly?
There are many ways to carb cycle. But you'll generally rotate between high- and low-carb days. Do intense workouts on heavier-carb days, but rest or keep it lighter on low-carb ones. Everyone's body is different, and you may need to adjust the meal plan along the way.
How long is it safe to carb cycle?
Experts aren't sure about its long-term benefits, but short-term carb cycling seems generally safe. Eating extremely low levels of carbs may lead to nutritional problems or muscle loss. And higher carbs and fiber can irritate your stomach. Make sure to balance your overall diet to keep your blood pressure, blood sugar, and cholesterol in a healthy range.
Is carb cycling good for fat loss?
Carb cycling is a short-term diet strategy for serious athletes and isn't proven for weight loss. The plan focuses on matching the amount of carbs you eat to your physical activity for the day.
What is the 5:2 rule of carb cycling?
The 5:2 rule for carb cycling means eating low-carbs for five days followed by two days of high-carbs. This keeps it simple, instead of keeping up with an alternating schedule.
