The metabolic confusion diet is an eating style that’s different from most other diets. Instead of aiming for a set number of calories each day, you alternate your daily calorie intake.
Though it is clearly a calorie restriction diet, it allows for more flexibility on a day-to-day basis. Proponents of the diet also believe it helps “trick” your metabolism into working harder and, as a result, makes you lose weight.
The popularity of the metabolic confusion diet is rising, and you may be wondering whether you should try it.
This article reviews the metabolic confusion diet and whether it actually helps with weight loss, as well as its benefits and downsides.
Diet review scorecard
- Overall score: 2.88
- Weight loss: 3
- Healthy eating: 3.5
- Sustainability: 3
- Whole body health: 2
- Nutrition quality: 3.75
- Evidence-based: 2
BOTTOM LINE: The metabolic confusion diet is an eating style that promotes cycling between high and low calorie days. While it’s more flexible than some traditional diets, it’s still a restrictive diet that may not be sustainable in the long term.
The metabolic confusion diet is also known as calorie cycling and calorie shifting.
It’s a dieting style that allows you to alternate between high calorie and low calorie days or periods of time. It also recommends regular exercise, though it doesn’t have strict exercise requirements.
One way to use the diet would be to alternate between high and low calorie intakes every other day. Alternatively, you might eat high calorie meals for a week and then eat significantly fewer calories the following week.
High and low calorie days will look different for each person. Though there’s no formal guideline, most programs suggest around 2,000 calories or more on higher intake days and no more than 1,200 calories on low intake days.
The metabolic confusion diet is similar to modified alternate-day fasting, which involves eating 25% of your normal calorie intake one day, followed by a day of eating whatever you want (
Similarly, the metabolic confusion diet is designed to keep your metabolism “on its toes” due to varying food intake (
However, a notable difference of the metabolic confusion diet is that it allows relatively more calories on low calorie days. Assuming most humans need 1,600–3,000 calories per day, 1,200 calories would equate to around 40–75% of your usual intake (
While this is still a restrictive diet, proponents believe it allows for more flexibility and more naturally matches a typical eating style. That is, some days you may eat more and others you may eat less due to factors such as your schedule and hunger levels.
Also known as calorie shifting, the metabolic confusion diet is an eating pattern in which you alternate between high calorie and low calorie intakes day-to-day or week-to-week.
The metabolic confusion diet, also commonly called calorie shifting, encourages daily exercise and eating below your daily calorie needs. Therefore, you’ll likely be in a calorie deficit that will lead to weight loss over time.
Proponents of the diet claim that alternating between high and low calorie days will “confuse” your metabolism and make it work harder since it will have to adapt to changes in calorie intake.
While you can’t really “trick” your metabolism, you may help prevent your metabolism from slowing.
Long-term calorie restriction, which is common in many weight loss diets, has been shown to decrease your resting metabolic rate (RMR) through a process called adaptive thermogenesis. This makes your body less effective at burning calories (
Proponents of the metabolic confusion diet believe it helps avoid this negative effect by allowing your body periodic breaks from calorie deprivation, thus preventing metabolic adaptations that hinder weight loss (
One study from 2014 supports this idea. The study compared traditional calorie restriction with calorie shifting over 42 days. One group of people consumed 1,200 calories per day, while the other restricted their calorie intake for 11 days and then had 3 days of unrestricted intake (
Participants in the calorie restriction group experienced a significant decrease in their RMR by the end of the study, while those on the calorie shifting diet maintained their prediet RMR (
What’s more, those on the calorie shifting diet lost significantly more weight, reported less hunger, and had greater adherence to the diet. The authors believe this style of eating allows for greater flexibility, which makes it easier to maintain in the long term (
On the other hand, a 1–year high quality study in 100 participants found no significant differences in weight loss between people who followed a calorie shifting diet and those who did traditional calorie restriction (
This may suggest that the diet’s effectiveness decreases with time, but scientists need to do more research to investigate further.
Considering that calorie shifting allows for greater flexibility and breaks from strict dieting, people who adopt this style of eating may report greater satisfaction, making it a more sustainable option for weight loss. However, more long-term research is needed (
Most research suggests that the most sustainable, healthy weight loss programs are those based on a nutritious diet and regular exercise to create a small calorie deficit of no more than roughly 500 calories per day (
Since you’re in a calorie deficit most of the time while on the metabolic confusion diet, you’ll likely lose weight. However, the name is inaccurate because this diet will not “confuse” or “trick” your metabolism.
The metabolic confusion diet may provide other benefits.
Allows for flexibility
Unlike traditional calorie restriction diets, the metabolic confusion diet allows you more flexibility in your food choices.
Since there are no formal guidelines, you can decide how many high calorie days you wish to have in a given time frame. This also makes it easier to enjoy food-related occasions such as birthdays, holiday meals, and parties.
Depending on how you choose to follow the diet, you may experience less hunger.
Following a low calorie diet long term will leave you feeling hungry and tired because your body won’t be getting enough energy for its daily functions. You’ll likely experience body signals encouraging you to eat, such as stomach pangs and low energy (
Unlike cheat days, which are designed to allow you to eat unlimited amounts of food, often to the point of feeling overfull, the metabolic confusion diet is designed to increase calories in a well-planned, intentional manner (
Ultimately, this may help prevent your body from feeling deprived, fend off hunger, and prevent binging or overeating. However, you may need to eat more than 2,000 calories on higher intake days, depending on your age, sex, body size, and activity levels.
Though it’s still a restrictive diet, the metabolic confusion diet allows for “breaks” from low calorie days. Depending on your calorie needs, this may allow for greater flexibility, less hunger, and fewer feelings of deprivation.
Though there are some positive aspects of the metabolic confusion diet, it also has many downsides.
You can have a few high calorie days on the diet, but most of the time you’re required to follow a strict low calorie diet of no more than 1,200 calories per day.
This arbitrary calorie recommendation is problematic because it doesn’t consider individual differences such as age, sex, body size, and activity level. Without accounting for these, you could severely underfuel your body.
For example, a 6′4″ (193 cm) man who weighs 230 pounds (104 kg) will need more calories than a 5′0″ (152 cm) woman who weighs 120 pounds (54 kg). Therefore, it’s important to select a calorie goal based on your body’s unique calorie needs.
Otherwise, highly restrictive diets like this one will be hard to sustain long term due to feelings of deprivation, hunger, and lack of enjoyment. The best diets are those that are satisfying, enjoyable, and easy to follow.
Lack of research
Though the theory of the metabolic confusion diet makes sense, there’s not much research on the topic. Most available research focuses on different versions of calorie shifting and alternate-day fasting, with little agreement among studies (
Furthermore, the human body is highly sophisticated and can easily adapt to changes in calorie intake. Your metabolism can’t get “confused” as the name of this diet suggests. Instead it shifts depending on how many calories you consume and burn each day (
To assume your metabolism would get confused after the occasional high calorie day greatly overlooks its impressive ability to keep your body functioning with day-to-day differences in calorie intake.
May not be sustainable
Even though proponents of the diet say it provides greater flexibility, it’s still highly restrictive and may be hard to follow long term.
Though the diet allows for periodic breaks, you must follow a low calorie diet of around 1,200 calories per day most of the time. Even then, “high calorie” days will still be on the low end of calories for some people, with most versions of the diet recommending 2,000 daily calories.
For example, daily calorie needs for men typically range from 2,000–3,000 calories, while women typically need 1,600–2,400 calories per day. The lower ends of these ranges are suitable only for people who do little to no physical activity (
Unless you’re including high calorie days often, such as every other day, it’s unlikely this will satisfy the hunger that results from many low calorie days in a row. Ultimately, this may be too depriving and hard to sustain.
It is still a diet
Although it’s different from and more flexible than many other diets, the metabolic confusion diet is still a restrictive diet that promotes fast weight loss.
According to research, most restrictive diets fail to produce long-term weight loss. Therefore, you may benefit from following a more sustainable healthy lifestyle that encourages a modest calorie deficit through a nutritious diet and increased physical activity (
Through this approach, you may lose weight without the need for a restrictive diet.
While you may lose weight on the metabolic confusion diet, it may not be sustainable long term due to its highly restrictive nature.
Although the metabolic confusion diet may be effective in the short term, there’s not enough research to support its long-term benefits.
You may lose weight on the diet, but it may be hard to follow for a long time because it’s very low in calories. If you enjoy or want to try this eating style, it’s best to incorporate higher calorie days more often to avoid feeling deprived and hungry.
For example, you could try to add 2 or 3 higher calorie days between lower calorie days during the week. This would provide you with more flexibility in your diet, which could make you more likely to stick with it long term.
However, most research has found that the healthiest and most sustainable approach to weight loss is to reach a modest calorie deficit of around 500 calories or fewer per day through eating mostly unprocessed foods and exercising regularly (
While you may be able to stick to the metabolic confusion diet more easily than to other restrictive diets, don’t expect to see a drastic change in your metabolism.
Although you may lose weight with this diet, it’s not due to a confused metabolism. Rather, weight loss likely results from being in a calorie deficit most of the time, having better control of your hunger, and feeling less deprived, which makes it easier to stick to the diet long term.
If you’re looking to lose weight but don’t want to severely restrict food, you’re better off following a healthy lifestyle that includes eating mostly minimally processed foods, exercising regularly, getting enough sleep, and managing your stress.