This article provides a detailed breakdown of the science and application of carb cycling. Carb cycling is a dietary approach in which you alternate carb intake on a daily, weekly, or monthly basis. People may use it to lose fat, maintain physical performance while dieting, or overcome a weight loss plateau.

Some people adjust their carb intake from day to day, while others may do longer periods of low, moderate, and high carb intake. A typical weekly carb cycling diet may include 2 high carb days, 2 moderate carb days, and 3 low carb days.

Protein intake is usually similar from day to day, whereas fat intake varies based on carb intake. A high carb day usually means low fat, whereas low carb days are high fat.

Carb cycling is an advanced diet strategy requiring more manipulation and programming than a typical diet. Carb cycling is a dietary approach in which you manipulate your carb intake depending on a variety of factors.

The science is primarily based on the biological mechanisms behind carbohydrate manipulation. Few controlled studies have directly investigated carb cycling diets 7, 8. For example, it provides carbohydrates around your workout or on intense training days. The high carb days also help your body replenish its supply of muscle glycogen, which may improve performance and reduce muscle breakdown 9 , Strategic high carb periods may also improve the function of the weight- and appetite-regulating hormones leptin and ghrelin 11 , Another big component of carb cycling is the manipulation of insulin The low carb days and targeting of carbs around workouts may improve insulin sensitivity, a vital marker of health Many more clinical studies with human participants are needed to find out whether carb cycling is safe and effective.

The proposed mechanism of carb cycling is to maximize the benefits of carbohydrates and teach your body to burn fat as fuel. While this makes sense in theory, more direct research is needed. The mechanisms behind carb cycling suggest that it can be beneficial for weight loss.

In theory, carb cycling may help you maintain physical performance while encouraging your body to burn fat for energy. As with any diet, the main mechanism behind weight loss is a calorie deficit, meaning that you eat less than your body burns over a prolonged period If you implement a carb cycling diet alongside a calorie deficit, then you will likely lose weight.

However, the complex nature of carb cycling may cause confusion and make it difficult for beginners to stick to the plan. In contrast, many people may enjoy the flexibility of carb cycling. This could probably improve adherence and long-term success for some people.

Many people believe that carb cycling can be beneficial for muscle gain and physical performance. The regular high carb periods and targeted carb intake may help improve performance 9.

Consuming carbs around workouts may also aid in recovery, nutrient delivery, and glycogen replenishment 16 , This may promote muscle growth.

However, some research suggests carbs are not necessary to build muscle if protein intake is sufficient While these mechanisms make sense in theory, direct research comparing carb cycling to other diets is needed to provide an evidence-based answer.

The mechanisms behind carb cycling suggest it can help you optimize performance. However, further research is required. As mentioned earlier, carb cycling has the potential to provide some benefits. By having periods of both low and high carb consumption, you may get many of the benefits of both diets, as well as the potential negatives.

Benefits of low carb periods may include improved insulin sensitivity, increased fat burning , improved cholesterol levels, and enhanced metabolic health 8 , 14 , 21 , High carb refeeds may have positive effects on hormones during a diet, including thyroid hormones, testosterone, and leptin.

High carb periods could also reduce inflammation and help your body use iron 12 , 16 , These factors may play an important role in long-term dieting success since hormones play a key role in hunger, metabolism, and exercise performance There may also be downsides to carb cycling.

For starters, a complex diet can be hard to maintain. Low carb periods may provide a number of health benefits, and high carb refeeds can have positive effects on your hormones. The long-term effects of carb cycling are not known. There are many variations of carb cycling, including daily alterations or longer periods of high and low carb intake.

Here is a sample week in which you regulate your carb intake on a daily basis:. Even more so than a typical diet, carb cycling can take a lot of fine-tuning and adjustment along the way.

You can experiment with the number of high carb days per week and the number of grams of carbs per day to find the best approach for your lifestyle, exercise routine, and goals.

If you prefer a low carb diet, you can add carb cycling occasionally in the form of a refeed. Here are some sample low carb plans with occasional high carb blocks:. As the table suggests, you can either refeed every couple of weeks or do long periods, such as a 4-week low carb phase with a 1-week refeed.

You will also notice that the number of carbs per day can vary drastically — this depends on activity level, muscle mass, and carbohydrate tolerance. An athlete who trains 3 hours a day or a pound bodybuilder may need the upper limit or even more , whereas an individual with a more moderate fitness level may need to refeed on only — grams.

These examples are only suggestions. There is no proven formula or ratio for carb cycling. Some dietitians specialize in making diet plans for athletes.

Carb cycling may not be appropriate for people with diabetes. There are several options for carb cycling, ranging from daily changes to monthly refeeds.

Consult a registered dietitian to figure out what works best for you and your goals. Here are three sample meal plans for low, moderate, and high carb days. Keep in mind that the total carbs per meal in these samples are estimates, not exact numbers.

Consider working with a dietitian to draw up a more precise plan that meets your particular needs. Some carbs should be enjoyed in moderation, including simple sugars and refined carbs, which are found in foods such as cakes, desserts, highly processed snack foods, and baked goods.

In contrast, there are plenty of healthy carb sources that are tasty and packed full of beneficial fiber , vitamins, and minerals. These include:. Limit refined carbs and added sugars. So while having all the greatest gear — including one of the best running watches on the market — can be a great asset come race day, carb loading is a vital part of preparation.

Athletes often load up on carb before a race or event that will last for several hours to ensure they have sufficient stores of glycogen. David Rogerson is a principal lecturer in sport and exercise science at Sheffield Hallam University in England, specializing in sport and exercise nutrition and strength and conditioning.

He has worked with sportspeople at all levels, from recreational athletes to elite-level performers competing at the Olympic games. The strategy of carb-loading to boost performance during endurance events is backed by science. According to a review published in the journal Applied Physiology, Nutrition and Metabolism , carb loading improves athletes' performance in endurance events lasting more than two hours, compared with a regular intake.

And while there has been a recent trend toward low-carb, high-fat diets among some athletes, research has shown that carbohydrate-based foods are key for fueling muscles.

A study of elite athletes published in in the journal Sports Medicine concluded that those competing in endurance events performed best after eating a high-carb diet, while eating a diet high in fat did not improve performance and actually impaired rates of muscle glycogenolysis, the process by which glycogen is broken down into glucose to provide immediate energy.

Eating carb-heavy foods like pizza, pasta or potatoes every day the week before a race might sound like a great way to load up on carbohydrates, but it could prove ineffective.

According to Rogerson, carb loading should be done in one day to maximize muscle glycogen storage. But this doesn't have to be the day before race day. So you could carb load two or three days beforehand and as long as you're not doing lots of exercise on those days, you'll probably still maintain those elevated levels of muscle glycogen going into the competition.

Carb loading works up to a point, but the body has a limit on the amount of carbohydrate it can store as muscle glycogen. This means that athletes need to consume additional fuel during long events. Too many carbs before a race can also lead to stomach issues and lethargy, so it's best to work with a sports dietitian to work out a suitable intake for you.

A pattern of carb loading for a day, resting for a day and then racing is one recommendation to try, said Rogerson. However, he advised a trial and error approach to work out what suits your stomach best. For activities lasting 90 minutes or less, there is no need for carbohydrate loading because the body already has enough glycogen stored, providing you are consuming a well-balanced diet that includes carbohydrates.

A Sports Medicine review of carb loading and exercise performance found that the nutrition strategy offered no benefit for moderate running or cycling up to 90 minutes.

Lily Canter is a freelance money, health and lifestyle journalist with more than 20 years' experience. She focuses on personal finance for Yahoo! Finance UK, Metro, The Guardian, and loveMONEY. In her spare time she is an ultra-runner, canicrosser and UK Athletics running coach.

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Jump to: What is carb loading?

Those who are interested in keto and running are on the complete opposite end of the spectrum. Essentially, carb loading before half marathon and carb loading before a marathon can both make a big difference when fueling for a marathon.

And it DOES matter what carbohydrates you choose — here are some of the best carbs for runners. For example, plugging numbers into this carb loading calculator, a person weighing pounds That is a hefty amount, and usually takes some planning and pre-planning to do this, or working with a dietitian.

You want to be strategic in how to include the best carb loading foods for running. It used to be standard for athletes to carb-load for over a week before a competition. However, current research suggests that athletes should carb-load no earlier than 48 hours before a competition.

More recent research indicates that carb-loading can be completed hours pre-race combined with a taper in training for days. This is where high carb lunch ideas for runners comes in handy. For more information, check out this sample long distance runners diet plan. It can also be helpful to refer to the performance plates for athletes , and modify from there.

When SHOULD you carb load, aka who benefits the most? Generally speaking, the longer the distance, the more the benefit. The types of exercise that benefit the most from carb-loading are the types that are likely to deplete your muscle glycogen stores, including endurance running.

Therefore, carb loading before a half marathon may be helpful if you plan on running anytime above 90 minutes. Similar to carb loading before a half marathon, carb loading for a marathon can be helpful and improve performance and decrease the perceived effort of exertion.

The main difference will be that while you may deplete glycogen stores during a half marathon, you may not. Hence, carb loading can be more widely relied upon, and the types of fuels you take during the marathon will also make a big difference. These nutrition tips for marathon runners are helpful in determining more about that.

There is an art to carb loading for running. It is important to choose foods that allow you to eat the right amount of carbs while avoiding GI issues.

Foods that are high in carbs while also being high in fat or protein may limit your ability to eat enough. Additionally, foods high in fiber may cause early fullness and gut problems. This can be a little more challenging for those who eat a lot of fruits and veggies or follow a vegan runner diet.

When talking about carbohydrates, there are two main types: simple carbohydrates and complex carbohydrates. For the purposes of carb loading before a race, we want to stick to mostly simple carbohydrates with less fiber white bread, white pasta, tortillas, certain fruits because they will be easier to digest and less likely to cause bloating and discomfort.

Additionally, it is generally better to eat familiar foods in the days leading up to a race, which is same period in which you would be carb-loading. This earlier meal allows plenty of time for the food to move through your system.

You can also carbo-load two days before if you will be too nervous to eat much the day before the event. The glycogen stays in your muscles until you exercise.

Then graze on crackers, chicken noodle soup, and other easily tolerated foods the day before your competition.

Learning the right balance takes practice. Hence, each long training session leading up to the endurance event offers the opportunity to learn which food—and how much of it—to eat.

This weight gain is good; it reflects water weight and indicates you have done a good job of fueling your muscles. For every ounce of carb stored in your body, you store almost three ounces water. Be sure to drink extra water, juices, and even soda pop, if desired.

Abstain from too much wine, beer, and alcoholic beverages; they are not only poor sources of carbs, but are also dehydrating. Drink enough alcohol-free beverages to produce a significant volume of urine every two to four hours.

The urine should be pale yellow, like lemonade. Be sure to take a look at the following article on drinking fluids. Many endurance athletes eat only carbs and totally avoid protein-rich foods the days before their event.

BAD IDEA. Your body needs protein on a daily basis. Hence, you can and should eat a small serving of low-fat proteins such as poached eggs, yogurt, turkey, or chicken as the accompaniment to most meals not the main focus , or plant proteins such as beans and lentils as tolerated.

Learn more about protein needs and the athlete by clicking the following link. PROTEIN: The Pros, Cons, and Confusion. Carb-loading is just part of the fueling plan. What you eat on the day of the event is critically important and helps to spare your limited muscle glycogen stores.

So fuel yourself wisely both BEFORE AND DURING the event—and hopefully you will enjoy miles of smiles! When carbo-loading, you want to consume about 3 to 5 grams carbohydrates per pound of body weight.

You can find carbohydrate info on food labels and www. If you have any concerns or questions about your nutritional needs, seek the consultation of a local sports nutritionist for appropriate care. Nancy Clark, MS, RD, CSSD is Board Certified as a Specialist in Sports Dietetics. She counsels casual and competitive athletes in her private practice at Healthworks, the premier fitness center in Chestnut Hill MA Her bestselling Sports Nutrition Guidebook and food guides for new runners, marathoners, soccer players and cyclists are available at www.

Carbo-loading: Tips for Endurance Athletes By Terry Zeigler, EdD, ATC Does carbo-loading mean stuffing myself with pasta?

Training Tactics The biggest change in your schedule during the week before your event should be in your training, not in your food. Fueling Tactics You need not eat hundreds more calories this week. Meal Timing NYC Marathon Queen Grete Waitz once said she never ate a very big meal the night before a marathon, as it usually would give her trouble the next day.

Fluids Be sure to drink extra water, juices, and even soda pop, if desired. Protein Many endurance athletes eat only carbs and totally avoid protein-rich foods the days before their event.

PROTEIN: The Pros, Cons, and Confusion Event day Carb-loading is just part of the fueling plan. Carbo-Loading Menu Ideas When carbo-loading, you want to consume about 3 to 5 grams carbohydrates per pound of body weight.