The Ultimate Guide to Carb Cycling

Tyler Spraul is the director of UX and the head trainer for Exercise.com. He has his Bachelor of Science degree in pre-medicine and is an NSCA-certified strength and conditioning specialist. He is a former All-American soccer player and still coaches soccer today. In his free time, he enjoys reading, learning, and living the dad life. He has been featured in Shape, Healthline, HuffPost, Women's...

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UPDATED: Aug 25, 2020

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  • Carbohydrate cycling is a diet strategy that many fitness competitors and bodybuilders use in order to prepare for a show.
  • The best way to carb cycle is to follow a plan that consists of three low-carb days and one high-carb day as part of a low carb, high protein diet.
  • When your intake of carbohydrates is low, your body is forced to use stored body fat for energy.

There is always buzz about what is the right amount of carbs for a healthy diet. Add in weightlifting and fat burning goals, and there is enough confusion to make a nutritionist’s head spin. With the right knowledge, you can use carb cycling to manage your metabolism, meet your goals, and stay healthy along the way.

At the most basic level, carbohydrates are sugar. Our mind doesn’t equate the two, but eating either a bowl of rice or a spoon of sugar both produce glucose.

When both are processed in the body, the final result is the same – they’re broken into glucose, which is the body’s best source of energy.

The only energy source for the brain and nervous system is glucose, unlike the muscular and skeletal systems. Also, carbohydrates (glucose) are the body’s most immediate energy source and have a 30-50% faster rate of breakdown compared to fat.

Anaerobic exercise relies exclusively on carbohydrates through glycolysis. Carbohydrates also have a protein-sparing effect, which keeps the body from breaking down protein for energy.

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Different Forms of Carbohydrates

Essentially, carbohydrates come in two forms, simple and complex. Simple carbs are mono and disaccharides which are “sugars.” Fructose, the naturally occurring sugar in fruit, sucrose (table sugar), and lactose (the naturally occurring sugar in dairy products) are some examples of simple forms. Complex carbs are things like rice, potatoes, pasta, and bread. These carbohydrates are polysaccharides or “starch.” They contain long chains of more than 3,000 glucose molecules linked together.

Now that the chemists and biologists are satisfied, let’s look at how these different carbs affect the body. Regardless of the form (except for fiber), the body converts carbohydrates into energy which is glucose.

The main difference between simple and complex carbs is the amount of time it takes the body to convert them into glucose.

Complex carbs tend to give a more gradual and sustained energy release. Simple carbs give an immediate energy release usually accompanied by a sharp decline in energy as well.

For this reason, it would be best to have more complex carbohydrates earlier in the day to provide a more prolonged energy supply. Have simple carbs after your workouts and exercise sessions for quick glycogen replenishment. Remember to keep in mind the glycemic index and load of the food sources.

One thing to realize is that once the carbs you have eaten have been converted to glucose, what is not used to fuel body functions and replenish muscle glycogen is shuttled into fat stores. Unused carbohydrates will, essentially, cause you to gain body fat. Your main goal with carbohydrates is to provide enough energy to fuel body functions and muscle activity each day and ‘no more.’  Therefore, the variable is carbohydrates if protein and fat intake remain the same each day.

What Is Carb Cycling?

Carbohydrate cycling is a diet strategy that many fitness competitors and bodybuilders use in order to prepare for a show. This tactic can also be used by anyone wanting a fat-blasting bodybuilding workout plan. When your intake of carbohydrates is low, your body is forced to use stored body fat for energy. Also, when your body has been given plenty of carbs, it uses them rather than fat as the energy source.

The body does require a certain amount of carbohydrates to carry out basic processes – such as brain function and the nervous system. We wouldn’t recommend going much lower than 120 grams of carbohydrates per day for this reason.

If your diet is too low in carbohydrates, your workouts and training are going to suffer. Anaerobic activity is fueled by carbohydrates. Also, you can fall into a state of ‘ketosis.’

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What Is Ketosis?

Ketosis is a state of carbohydrate deprivation and should be avoided. Ketone bodies are the product of incomplete burning of fats. When these are present in the blood, your body doesn’t have enough carbohydrates available in order to properly metabolize body fat. In other words, you need carbs to burn body fat! The body can use ketone bodies instead of glycogen for energy production, but they are nowhere near as efficient in fueling exercise.

When you are in a state of ketosis, you become irritable, sluggish, and may become dehydrated. Without carbohydrates available in the body, your body breaks down protein for additional energy (a catabolic state). Your body will actually metabolize muscle tissue for energy at about the same rate as fat if you don’t have enough protein intake. Your hard-earned muscle will be metabolized.

This is obviously counterproductive for someone trying to build or maintain lean muscle mass. When considering a muscle-building strategy, the last thing you want to do is jeopardize your efforts with the possibility of the strategy backfiring. Make sure you watch out for the effects of ketosis when carb cycling.

The correct way to carb cycle is to make sure you are taking an adequate amount of protein and not limiting your carbohydrates to the point of ketosis. Ketosis can be monitored by using ketosis strips.

These strips can be found at many pharmacies and contain a special chemical that will change color in the presence of ketones in the urine. The container will have a scale on the label, with blocks of color to compare to the strip. You check for ketosis by passing the strip through your urine. The ketosis strip will turn a certain color after about 15-20 seconds.

Low and High Carb Amounts

The best way to carb cycle is to follow a plan that consists of three low-carb days and one high-carb day as part of a low carb, high protein diet.  You continue to cycle the days until you reach your desired goal. The high-carb days are important for a few reasons.

Firstly, it throws your metabolism off and tricks your body into thinking it has come off the diet. If you continue to have low-carb days, your body will eventually adapt to this and slow its metabolism down to compensate for the lower caloric intake. This is known as homeostasis, your body trying to maintain a balance.

Having a high-carb day “fools” the body. But, after a longer period of time, your body will adapt to the three low-carb days and one high-carb day as well.

Another reason to have high-carb days is to replenish glycogen stores. Glycogen is the body’s storage form of carbohydrates found in the liver and muscles.

Since glycogen is combined together with water, the extra volume in the muscle cells causes the muscles to appear larger. Muscles deprived of glycogen are small and flat whereas muscles full of glycogen are big and full.

The final reason to have high-carb days comes from a health standpoint. After following a strict low-carb diet for three days in a row, you can become mentally and physically drained. For this reason, you should give your body a break from the routine every fourth day. After the high-carb day, you will again feel full of energy, more alert and ready to go into the next three days.

Check Your Progress

After doing the carb cycling for 4-6 weeks, you should reevaluate what progress you have made. If you’re getting close to your desired body fat, you may want to cut back to two low-carb days and one high-carb day.

This will prevent your body from adapting and slowing down its metabolism. You could even cycle low, moderate, and high carbohydrate days to “throw” your body off.

When you have reached your desired body fat level, you can alternate low-carb and high-carb days, or even have ‘moderate’ carb days all week long.

The best measure of progress is how you look in the mirror and how you are feeling. The scale, tape measure, and your body fat percentage can only say so much.

We have outlined a sample low and high carb day that can be used. The high-carb day also incorporates higher glycemic index carb sources. If you get hungry in the middle of the night on the low-carb days, we’d recommend having a scoop of protein to keep you going until the morning. When it comes to fat loss, carbohydrates are the variable. After you have reached your desired goal, you can follow more general guidelines that will become a part of your everyday lifestyle.

Low-Carb Day

Meal 1:  5 egg whites, 2 yolks. 4oz. turkey burger, 8 strawberries or a pear.
Meal 2: 6oz. chicken breast, half cup of oatmeal.
Meal 3: (Post-workout)   2 scoops of whey protein, half tbsp lecithin granules.
Meal 4: 6oz. chicken breast, 2-3 cups of mixed green salad, 1tbsp olive oil and vinegar.
Meal 5: 6oz. chicken breast, 1 cup of broccoli or green beans.
Meal 6: 4oz. turkey burger, 5 egg whites, 1 cup of vegetables for the omelet.
Meal 7: 1-2 scoops of casein protein, 1 tbsp flaxseed oil.

High-Carb Day

Meal 1: 9 egg whites, 1 cup of oatmeal, half cup of raisins.
Meal 2: 6oz. chicken breast, 1 cup of oatmeal, 1 banana.
Meal 3: (post-workout)  2 scoops of whey protein, half tbsp lecithin granules.
Meal 4: 6oz. chicken breast, 1 cup of brown rice, 1 cup of broccoli or green beans.
Meal 5: 6oz. chicken breast,6oz. baked potato, 1 cup of mixed green salad, 1 tbsp olive oil and vinegar.
Meal 6: 4oz. turkey burger, 5 egg whites, 1 apple or pear.
Meal 7: 1-2 scoops of casein protein, 1 tbsp flaxseed oil.

Sample Weekly Carb-Cycling Plan

Sunday:  Low
Monday: Moderate
Tuesday: Low
Wednesday: High
Thursday: Low
Friday: Low
Saturday: High

When used correctly, carb cycling can be a very effective way of losing body fat while preserving your muscle mass.

Those taking their muscle-toning and fat-burning to the next level should consider carb cycling and this sample meal plan to reach their goals. Weight training is never dependent on one secret strategy. Carb cycling is one element of a successful fitness lifestyle, but it should be accompanied by overall healthy eating and weightlifting.

Frequently Asked Questions (FAQ)

How many calories should I eat?

How many calories you should eat depends on a number of factors. To get a rough estimate, check out this article.

What is bulking? What is cutting?

Bulking and cutting are techniques used by bodybuilders to grow muscle and shed fat. Bulking requires eating in a surplus while weight training in order to build muscle. Cutting requires eating in a caloric deficit to shed body fat in order to “expose” the muscle built during the bulking phase.

Do I have to bulk? Do I have to cut?

No. Unless you are a professional bodybuilder, you do not have to bulk or cut to lead a healthy, happy lifestyle.

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