How does the Carb Cycling diet work?

What is Carb Cycling?

Carb Cycling is a method of alternating high and low carbohydrate days. This approach can help you lose weight by increasing your metabolism and burning more fat. On high carbohydrate days you will eat foods such as bread, rice, pasta and fruit. These foods will give you energy for your workouts. On low-carb days, you focus on eating protein-rich foods such as meat, fish, eggs and vegetables. These foods will help keep your energy levels up while keeping your carbohydrate intake low

The idea behind the carbohydrate cycle is that by alternating high carbohydrate days and low carbohydrate days, you can maintain your energy levels while burning more fat. When you eat carbohydrates, your body breaks them down into sugar, which is then used for energy. However, if you eat too many carbohydrates, your body stores the excess sugar as fat. By alternating days when you eat a lot of carbohydrates and a little, you can ensure that your body uses the carbohydrates for energy rather than storing them as fat.

In addition to weight loss, the carbohydrate cycle can also help improve your health. Carbohydrates are an important part of a healthy diet and can provide your body with the nutrients it needs to function properly. However, when you eat too many carbs, they can cause problems such as insulin resistance and inflammation. By eating fewer carbohydrates on certain days, you can reduce these effects and improve your overall health.

Carb cycling is also a great way to stick to your diet. When you have days when you can eat carbs, it can be easier to stick to your diet and avoid cravings. By alternating high-carb days with low-carb days, you can find the perfect balance for your body and lifestyle

Who is Carb Cycling for?

This method can be suitable for people who want to increase muscle mass, lose body fat or maximize their training and recovery. You can also try carb cycling if you have reached a plateau in your progress.

This requires substantial forward planning and may not be suitable for all lifestyles.

Carb Cycling is used by some athletes to match their energy intake to their training program, with higher carbohydrate intake on training days and lower intake on rest days.

When used in this way, Carb Cycling can help maximise the quality of each workout by making carbohydrate energy readily available to the muscles during a workout and promoting faster muscle recovery after a workout.

Another way to use carb cycling is to include scheduled "refeedings" during an extended period of low carbohydrate consumption. This helps reset your body and is especially important if you have been in a calorie deficit. Also, you are more likely to stick to your low-carb days when you have a high-carb day.

It is important to note that carb cycling is not recommended for anyone who is pregnant, diabetic or hypoglycemic. The method is also not recommended for people with a history of eating disorders. Always consult a health care professional before making any changes to your diet.

What should I eat when Carb Cycling?

On high carbohydrate days, focus on eating complex carbohydrates. Complex carbohydrates contain more essential nutrients and fibre and are found naturally in plant foods. You will aim to get about 50-70% of your diet from high quality carbohydrate sources.

Sources of complex carbohydrates include:

• Sweet potato
• Whole grain rice
• Fruit
• Oats
• quinoa

On low carb days you can still include a piece of fruit, but you'll get more of your nutrition from nuts, low carb vegetables like olives, tomatoes, spinach or kale, and protein sources like fish, chicken or eggs. Carbohydrates will make up about 20% of your nutritional intake.

On days without carbohydrates, you aim to consume 50 g of carbohydrates, which is less than 10% of your total energy intake.

Don't set these days if you are scheduling a high intensity workout, more than 30 minutes of cardio, or if you need to be mentally focused, as you may have less energy and your ability to focus may be compromised when you eat very little.

Increasing your portions of nuts, avocado or oily fish to include more healthy fats on low carb days can help you feel full throughout the day.

How to use Carb Cycling to gain muscle mass

When you eat carbohydrates, glucose is released into the bloodstream more quickly than with other types of food. This spike in blood sugar increases the rate at which insulin is released into the bloodstream.

Insulin is a hormone that is made in the pancreas in response to signals from your brain that food is being eaten. It helps regulate your blood sugar by signaling your cells to absorb nutrients and energy into the bloodstream.

By increasing the absorption of glucose and amino acids into muscle tissue, insulin also facilitates muscle repair and growth.

On moderate and intense training days, carbohydrate and protein intake will help maximise muscle growth and recovery.

On low carb days, which usually coincide with a rest day if your goal is to gain muscle mass, insulin levels will not usually rise as high. This prevents your body from storing too much energy as fat.

In this way, the carbohydrate cycle can be used to promote muscle growth and minimise energy storage in the form of adipose (fat) tissue - exactly the result most of us are trying to achieve!

Benefits of Carb Cycling

The method can have beneficial effects on health and fitness when used as part of a balanced and holistic diet.

Insulin sensitivity can improve

Insulin is a hormone that helps the nutrients in food move from your bloodstream into the cells of your body. When you eat, insulin is produced by the pancreas. As the food in your meal or snack is absorbed by the body, insulin levels in the blood decrease.

High insulin sensitivity occurs when the body's cells respond quickly to insulin in the blood, absorbing nutrients to reduce blood sugar levels quickly after a meal.

Low insulin sensitivity occurs if your cells do not respond to high levels of insulin. Nutrients and sugars continue to circulate in the blood longer and insulin levels remain high for longer.

Consistently high levels of insulin promote the storage of energy in the form of glycogen (a readily available source of energy in the muscles) and fat and can disrupt the production of leptin and other appetite-regulating hormones.

The carbohydrate cycle to include low-carb days can help your body adjust its insulin response to food, improving insulin sensitivity and nutrient absorption.

Increased fat burning

Carb Cycling can be a way to moderate your energy intake. This means you may have a lower total energy intake on low carb days and a higher total energy intake on high carb days.

Increased insulin sensitivity can also promote fat burning. High levels of insulin in the blood promote the storage of blood sugar as fat. Increased insulin sensitivity decreases the length of time that insulin levels remain high and may reduce the amount of energy from food stored as fat.

Risks of Carb Cycling 

Reducing carbohydrates carries some risk. You can minimise the impact of reducing carbohydrate intake by making informed decisions about what foods to include on low carbohydrate days.

Your brain works with carbohydrates

Even on low carb days, you need to include carbohydrates to help you stay alert and focused throughout the day. This can come from the fruit or vegetables included in your low-carb meals and snacks.

Your brain depends on glucose for fuel, a sugar produced when starchy foods are broken down by the body. It has been shown that your brain can use more glucose during difficult mental tasks than when you are at rest.

While the body's muscles can use fatty acids as fuel when carbohydrate intake is low, the brain can only use glucose. When blood sugar levels fall too low, short-term memory and attention can be compromised. When glucose is introduced after fasting, memory improves.

This means that eating regular meals with carbohydrates can improve your mental performance.

When there are no carbohydrates available in your bloodstream, your body may rely on other sources of glucose for the energy your brain needs, such as protein. This can be detrimental if one of your goals is to build lean muscle mass.

Getting enough fibre on low-carb days

Lower carbohydrate intake can mean lower fibre intake when you reduce the amount of fruit and whole grains in your diet. You can get fibre and important nutrients in these foods from other sources, including cauliflower, broccoli and other cruciferous vegetables.

Eating plenty of other fibre-rich foods and drinking water will minimise the impact of reduced fibre from carbohydrates.

What to consider when Carb Cycling

When cycling for carbohydrates, the types of food you choose to eat on high and low carbohydrate days should help you meet your overall nutritional needs.

The type of carbohydrate you eat still matters

Even on high-carb days, you should look for sources of carbohydrates that satisfy you and provide the nutrients your body needs.

For example, white bread and broccoli are both sources of carbohydrates, but they are processed very differently by the body. Complex carbohydrates from whole food sources, such as broccoli, contain important fibre and micronutrients to support your health and fitness goals.

Highly processed carbohydrates, such as white bread, generally lack the nutritional value of complex carbohydrates. The simple sugars in processed carbohydrates are rapidly absorbed by the body, causing an increase in insulin production.

This can be counterproductive if one of the benefits you want from the carbohydrate cycle is to increase insulin sensitivity or reduce body fat.

Eat enough protein on high-carb days

Protein in your diet is essential for maintaining lean muscle mass. This means that you should include protein-rich foods in your meals and snacks, even on high-carb days!

Proteins have a 'high heat effect', which means that a significant amount of energy is required to digest and absorb them into the body - about 10% of the energy in proteins is used to metabolise them.

This means that the inclusion of protein during your high carbohydrate days can be done effectively without exceeding your energy requirements.

Carb Cycling versus the Keto diet

Carb Cycling and the Keto diet both involve reducing carbohydrate intake. So what is the difference between these two diets?

The keto diet allows 20-50g of carbohydrates per day, or 10% of total energy intake. This very low carbohydrate intake causes the body to enter "ketosis", where the body uses stored fat for energy instead of glucose.

During carb cycling you will not usually go into ketosis. On low carb days, your carbohydrate intake may be 50-150g. These carbohydrates usually come from vegetables and non-starchy dairy products. It 

Eating a healthy, balanced diet is the most sustainable way to achieve your health and fitness goals! However, if you are curious and want to know more about diets ask a dietician who can provide advice specific to you and your training program.