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Calorie cycling, also called calorie shifting or an intermittent energy restriction diet, is an eating pattern that may help you stick to your diet and lose weight.

Rather than consuming a set number of calories daily, you alternate your intake. There are no food restrictions or strict guidelines, just the number of calories you can eat on certain days or weeks.

For this reason, it’s not a “diet” in the conventional sense, but rather a way of structuring your weekly or monthly food intake.

Research suggests the benefits of calorie cycling include greater weight loss, improved ability to stick to a diet, less hunger, and a reduction in the negative hormonal and metabolic adaptations of a normal weight loss diet.

What’s more, you can do calorie cycling however it works best for you.

Although this is a fairly new approach, hunter-gatherers likely had a similar eating pattern centuries ago because food was not available in the same amounts every day.

There were periods when food was scarce and other times when it was abundant, depending on the time of year and degree of hunting success.


Calorie cycling is an eating pattern in which you cycle your calorie intake from day to day or week to week.

Most conventional diets fail

To understand why calorie cycling may be beneficial, you need to understand why conventional diets can be unsuccessful in the long term.

A 2001 review of weight loss studies found that most people regained more than half the weight they had lost within 2 years. By 5 years, they had regained more than 80% of the lost weight.

More recently, a 2016 study of contestants from the TV show “The Biggest Loser” found that those who lost the most weight also experienced an increased slowing of their resting metabolic rate.

Six years later, the contestants had gained back on average about 90 pounds of the weight they’d lost and continued to have a slower resting metabolic rate.


Studies show that most dieters regain most of the weight they initially lose and often end up weighing even more than before.

Metabolic adaptations to normal diets

Many studies highlight the metabolic adaptations and psychological factors that cause diets to fail in the long term.

The adaptations caused by dieting suggest that your body senses it as a potentially dangerous state.

Centuries ago, a low calorie period of time could equate to starvation or illness. To survive, the brain would send various signals to the body to preserve energy.

It does this via numerous biological changes, which are collectively called metabolic adaptations. These negative adaptations include:

  • Decrease in testosterone. Testosterone is a key hormone that can decline to low levels during dieting.
  • Decrease in resting energy expenditure. This decline is also known as adaptive thermogenesis and is sometimes called “starvation mode.”
  • Decrease in thyroid hormone. This hormone plays a key role in metabolism. Its levels often decline during dieting.
  • Decrease in physical activity. Physical activity tends to decline when dieting and may be a key factor in obesity and weight regain.
  • Increase in cortisol. This stress hormone can cause many health issues and play a role in fat gain when levels are constantly elevated.
  • Decrease in leptin. This important hunger hormone tells your brain you are full and to stop eating.
  • Increase in ghrelin. Often seen as the opposite of leptin, ghrelin is produced in your digestive tract and signals to your brain that you are hungry.

These adaptations are the exact opposite of what you need for successful long-term weight loss. These changes could occur to some degree with calorie cycling as well.


A typical low calorie diet will negatively affect hunger, hormones, and metabolism. These changes make it very hard to maintain weight loss in the long term.

Your hormones work against you

Your body does everything in its power to slow down weight loss, conserve energy, and even regain the weight after dieting.

Changes to weight-regulating hormones play a key role in this. Like a seesaw, leptin decreases hunger and ghrelin increases it.

During a 6-month study in 2002, diet-induced weight loss of 17% of body weight increased ghrelin levels by 24%. The researchers noted that this was consistent with the belief that ghrelin plays a part in long-term regulation of body weight.

In a 1997 study, when participants lost 21% of their body weight, their leptin levels decreased by more than 70%.

This is one potential benefit of calorie cycling, as higher-calorie periods may reduce ghrelin and increase leptin.


Dieting can cause an increase in the hunger hormone ghrelin and a decrease in the fullness hormone leptin. Calorie cycling may help by reducing these negative hormonal adaptations.

Research on calorie cycling

Some studies have found sharp declines in the number of calories people burn per day when cutting calories.

In one 2014 study, participants spent 11 days on a low calorie diet followed by 3 days of eating more calories (termed a “refeed”). Four weeks after treatment, some significant weight loss and fat loss had started, and both continued up to a 1-month follow-up.

In other cases, studies have looked at longer 3- to 4-week diets with 1-week refeeds.

As shown in the graph below, a 2001 study found almost a 250-calorie reduction in calories burned at rest after 8 weeks on a weight loss diet.

Another study found that a 3-week low calorie diet decreased metabolism by more than 100 calories. However, when participants switched to a higher-calorie diet in the fourth week, their metabolism increased to above starting levels.

A 7-week study of resistance-trained participants found that during an energy-restricted diet, a consecutive 2-day carbohydrate refeed more effectively prevented the loss of fat-free body mass than continuous energy restriction.

Those participants’ resting metabolic rates were also slightly better maintained.

A review found that intermittent energy restriction diets had more effect on weight loss than continuous energy restriction diets, but the researchers noted that longer trials are necessary to confirm this.

However, other research has found little difference between the benefits of intermittent and continuous energy restriction diets.

Research reviews in 2021 and 2018 concluded that the two types of diet have similar effects on weight loss.

Overall, according to the National Institute on Aging, more research is needed to fully understand the long-term health benefits of calorie cycling.


Research suggests that an intermittent energy restriction diet with periodic high calorie days may increase your metabolism and hormone levels more successfully than a continuous energy diet, but further studies are needed.

How to implement calorie cycling

There are no definitive rules for implementing calorie cycling or higher-calorie periods.

If you’re interested in giving calorie cycling a try, you can stick with a dietary approach that works for you and then add these high calorie periods intermittently.

After a few weeks on a low calorie diet, you may notice physical effects such as a decrease in energy, workout performance, sleep, or sex drive or a fat loss plateau. This is when you may want to add a higher-calorie period.

It’s best to listen to your body and give it a few days to recover and refuel before the next dieting period.

Some people enjoy having higher-calorie days every week — for example, 5 low calorie days and 2 high calorie days.

Others like to get into a set routine and diet for a strict 2–4 weeks before adding slightly longer 5- to 7-day high calorie periods.


Follow a diet you can enjoy and stick to, and then simply add higher-calorie refeeds periodically based on your body’s feedback and results.

Combine calorie cycling with exercise

Since exercise plays an important role in health and weight loss, it makes sense to tailor your calories to your activity level.

The varying demands of exercise can drastically change your calorie needs on any given day.

Therefore, it makes sense to schedule your longest and most intense exercise sessions on high calorie days. On the other hand, save the lighter exercise sessions or rest days for your low calorie days.

Over time, this can allow you to lose fat but still maximize performance when it’s most important.

However, don’t make your routine too complex. If you exercise only for health and weight loss, you can keep it simple and follow the example protocols listed above.


Base your high calorie days and refeeds around intense training blocks or sessions, and tailor your low calorie periods around training that’s less intense or less of a priority.

Calorie cycling or shifting is a technique that may improve dieting success.

It may play an important role in protecting your metabolism and hormones, which can often plummet during typical low calorie diets.

Yet despite its benefits, it’s not a magical way to lose weight.

You still need to focus on the basics, such as achieving a long-term calorie deficit, eating nutritious foods, exercising and getting enough protein.

Once these habits are in place, calorie cycling can certainly help improve long-term success.