While carbohydrates make up the largest percentage of most people’s daily caloric intake, we can change the amount of carbs we eat to encourage weight loss, boost physical performance, and lower the risk of some health conditions caused by processed foods. One popular dietary approach here is carb cycling – so read on as we explain what carb cycling is, and how you can use it to optimize your fitness.
Below, we’re unpacking carb cycling – equipping you with a carb cycling meal plan and exploring the related concept of nutrient timing for muscle gain. We’ll also be walking you through what the best time of day to eat carbohydrates is, and how you can use carb cycling for weight loss – or to fuel a range of other key fitness goals.
What is carb cycling?
Carb cycling is a short or long-term diet plan where one varies the amount of carbs they eat. This can mean altering your carb intake by day, week or month. The most common reason people carb cycle is for weight loss.
Carb cycling meal plans were popularized by professional athletes who plan high carb periods for training, followed by low-carb periods to achieve a certain weight or body fat percentage for competition. Weight classes are common in a variety of sports such as weightlifting, rowing or boxing. What works for pro athletes can also work for the community at F45, and if you want to kickstart your exercise in a supportive environment, find your nearest F45 studio to get started.
How does carb cycling work?
The goal of carb cycling is to eat a diet that maintains physical performance and consistent weight loss. Below, we’ll explore how carb and other macronutrients in a carb cycling meal plan can change to reflect a workout routine.
Carb cycling: training periods
Carbs are the only macronutrient that can be broken down quickly enough to deliver energy for high-intensity workouts1.
When carb cycling, training periods usually contain a high-carb intake. This is so you can perform to the best of your ability, helping you build muscle mass and unlock the full breadth of aerobic exercise’s benefits for your health.
Carb cycling: recovery periods
During recovery periods, your carb intake may change depending on your current weight goals:
- A moderate carb intake will replenish energy stores while maintaining your current weight.
- A low-carb intake will restore energy less efficiently but encourage more weight loss.
Fat and protein consumption during recovery will be similar to training periods. This is because protein facilitates muscle recovery2.
Nutrient timing explained
Nutrient timing is the practice of eating specific macronutrients – carbs, protein, and fat – at certain times of day to optimize performance, recovery, and body composition. Rather than focusing on cutting out entire food groups, nutrient timing takes a balanced, strategic approach. For example:
- Carbs: Best consumed around training to fuel effort and replenish energy.
- Protein: Best spread evenly throughout the day to support muscle repair and growth.
- Fats: Provide satiety and support hormone function, usually consumed in moderation away from workouts.
For those smashing an F45 group fitness class, this means structuring what you eat so you’re energized before class and recover well afterwards. Meal prepping for the week also helps you maintain a healthy, sustainable eating pattern long-term.
How carbs fuel your workout
Carbohydrates are your body’s preferred source of energy for high-intensity exercise. When you take part in an F45 workout, your body relies heavily on glycogen – stored carbs in your muscles and liver – to power through resistance sets, sprints, and cardio blocks.
Simple carbs (like bananas or sports drinks) provide quick, accessible energy. They’re ideal before a session or midway through a particularly tough cardio day.
Complex carbs (like oats, rice, or sweet potato) release energy more slowly, supporting endurance and helping your body recover after training.
When carbs are timed well, you’ll notice stronger performance, more stamina, and less fatigue mid-session.
When is the best time to eat carbs?
Are carbs better in the morning or evening? Here’s a quick breakdown.
Morning
Your body is more insulin sensitive earlier in the day, which means it processes carbs more efficiently. Eating carbohydrates in the morning can help fuel workouts, stabilize blood sugar, and support weight management. This is often considered the best time of day to eat carbohydrates, especially if you’re active before lunch.
Pairing whole-food carbs such as oats, fruit or whole grain toast with protein also helps you get more vitamins and minerals in your day. Not sure how much protein you need? Our in-depth, research-backed guide will help.
Evening
Large carb-heavy meals at night are more likely to be stored as glycogen or fat if you’re not active. If your training takes place in the evening, focus on moderate portions of complex carbs – like quinoa, sweet potato or lentils – to replenish energy stores and aid recovery without overloading your system.
The best rule of thumb? Align your carb intake with your workouts. If you train in the evening, you’ll still benefit from carbs beforehand for energy, and complex carbs afterwards to support recovery. If you’re training in the morning, the best carbs to eat in the morning are nutrient-dense options like oats, bananas or berries, which not only provide sustained energy but also help you meet your micronutrient needs.
Nutrient timing for different goals
How you time your meals and carb intake will depend on whether your focus is nutrient timing for weight loss, muscle gain, or peak performance.
While the principles of carb cycling remain the same, adjusting when – and how much – you eat around training can make a big difference to your results.
Nutrient timing for weight loss
For weight loss, focus on carbs earlier in the day and around workouts. Aim for low-GI carbs (like oats or whole grains) for breakfast, and keep evening meals lighter on carbs, going heavier on the protein and vegetables.
Want to learn more about weight loss, and how strength training can support it? Our in-depth guide has you covered.
Nutrient timing for muscle gain
If your goal is building muscle, prioritize carbs around training sessions. A high-carb pre-workout meal gives you energy to lift heavier, while pairing carbs with a post-workout protein smoothie helps muscle repair and growth.
Nutrient timing for peak performance
For high-output training – such as building your running endurance, or training for your first HYROX race – complex carbs (brown rice, quinoa, beans) should form the foundation of any meal before you get started.
Simple carbs – like those found in fruit or the best gut-healing smoothies – can be added before or during intense sessions for a quick energy lift.
How to integrate carb cycling: 7-day carb cycling plan
We’ve gone in-depth on the reasoning behind carb cycling, now let’s outline what an actual week could look like. It’s important to note that this is just one example, the important part is to understand the fundamentals behind a carb cycling meal plan so you can apply it to your own workout routine.
Below, you’ll find examples of what each type of day might look like, along with suggested meal and nutrient timing to match your workouts.
Sunday and Monday (High carb intake)
High-intensity training days, where you might look to challenge your body and mind with an F45 hybrid workout. Here carbs should make up approximately 45 to 50% of your total caloric intake, or about 175 to 180 grams of carbs per day.
For a high-carb day, your carb cycling meal plan could contain the following:
- Breakfast: Oatmeal with milk, mixed with preferred fruit (50g).
- Snack: Cottage cheese with a few crackers and an apple (25g).
- Lunch: Wholewheat wrap with chicken, cheese, tomato and romaine (48g).
- Snack: Plain Greek yoghurt with mixed berries and granola (30g).
- Dinner: Baked cod and potato, with a side of steamed vegetables (54g).
Tuesday to Wednesday (Moderate carb intake)
Here, we’re performing a light training workout or recovery session.
This means carbs should make up approximately 25 to 40% of your total caloric intake, or about 140 to 170 grams of carbs per day.
Your medium-carb cycling meal plan this day might include:
- Breakfast: Three-egg omelette, with two slices of whole wheat toast and a banana (40g).
- Snack: Apple (15g).
- Lunch: Baked chicken with rice and broccoli (33g).
- Snack: Banana (23g).
- Dinner: Pesto pasta (30g).
Thursday to Saturday (Low carb intake)
Rest days, where we may be doing no physical activity or something very light such as a walk. The final three days of the week are low-carb days. On these days, your energy usage is low – so you can replace carbs with another macronutrient.
This means approximately 20 to 25% of total daily caloric intake, or about 115 to 130 grams of carbs per day.
The usual option here is to eat more fat, as this encourages the body to use the fat for fuel rather than carbs, promoting weight loss3. To read more about how you can eat more to lose weight, our guide has the full take.
Round out your 7-day carb cycling meal plan with a low-carb day like this:
- Breakfast: Bacon and eggs with avocado (15g).
- Snack: Celery with peanut butter (4g).
- Lunch: Baked fish with a tomato, red pepper and red onion salad (21g).
- Dinner: Chicken with spinach and rice (25g).
Remember, our carb cycling meal plan is just one way you can optimize your nutrition. There are a variety of ways to carb cycle, and we encourage you to see a dietician or physician before beginning any new diet.
Next, learn how to stay motivated and achieve big with F45.
