One plate with salmon and a salad next to a plate with a burger and fries

What Is Metabolic Confusion? Does It Actually Work?

Metabolic confusion sounds as murky as its name. A registered dietitian explains all.

When it comes to losing weight, deciding what meal plan to follow is half the battle. The rest of the fight? Hunger, cravings, and the resulting mood swings. Absent a miracle weight loss pill, the best hope we have is a diet that promises to avoid the aforementioned.

That’s the claim of metabolic confusion, an alternate day fasting diet that shifts between periods of high-calorie and low-calorie intake.

The diet purports to keep your metabolism humming and your satisfaction levels high—a theoretical combo that sounds like a recipe for success.

Does metabolic confusion work? And is it safe? We tap Imashi Fernando, MS, R.D., to find out.

What Is Metabolic Confusion?

Metabolic confusion, also known as a calorie shifting diet or calorie cycling, is the practice of alternating your calorie intake between higher and lower amounts. The goal of this diet plan is to trick your metabolism into staying high, and thus, burning more calories.

“Weight loss is about energy balance. A lower resting metabolic rate (RMR)—the number of calories your body burns at rest—would make it more challenging to promote continued weight loss,” Fernando says. Your body responds to long-term caloric restriction by slowing down your metabolism (1, 2, 3, 4). This unwelcome dip can lead to weight loss plateaus (and obvious frustration).

“Instead, the thought with metabolic confusion is that shifting between high-calorie and low calorie periods of eating will confuse your metabolism into maintaining your RMR,” says Fernando. “Effectively, avoiding the typical drop in RMR seen in other low-calorie diets.”

How does metabolic confusion differ from intermittent fasting?

Metabolic confusion is most similar to the 5:2 intermittent fasting diet, where you eat normally for five days and then severely restrict calories for two days (i.e. 800 calories a day). Though both diets differ from traditional intermittent fasting, which typically restricts eating to a set window of time each day. 

Does Metabolic Confusion Work to Lose Weight?

“Maybe,” says Fernando. If it does work, she notes the scientific evidence is slim; just one study.

The study, published in the Journal of International Preventative Medicine, found that when compared to traditional calorie restriction (1,100 calories per day) calorie shifting (11 days of 1,100 calories, and 3 days unrestricted) was associated with more weight loss, less hunger, and greater diet adherence over 42 days (5).

What’s more, participants who shifted their calorie intake were able to maintain their pre-diet RMR, while calorie restriction led to a significant decrease in RMR.

However, another study—which followed participants for one year—found that there was no significant difference between calorie shifting and calorie restriction on weight loss and maintenance (6). A recent review agreed and cautioned against the unknown safety and metabolic health implications of calorie shifting—noting further research is needed (7).

There is more evidence that metabolic confusion works, but it suggests that the secret isn’t tied to metabolism. According to a review published in Obesity Review, since calorie shifting allows greater flexibility, breaks, and satisfaction it might be more sustainable than calorie restriction long term (8).

“If you struggle with sticking to caloric restriction, metabolic confusion may offer an alternative that allows you to take breaks from low-calorie eating while maintaining an overall slight caloric deficit long term,” says Fernando. “However, it is important to emphasize that the long-term effects on health are currently unknown.”

Is the Metabolic Confusion Diet Plan Safe?

“As long as it’s not practiced in an extreme manner—for example, eating fewer calories (i.e. 800 calories) for five days, followed by higher calories (i.e. 3,500 calories) for two days—it should be fine,” says Fernando.

Most research suggests the most sustainable, healthy weight loss programs rely on a nutritious diet and regular exercise to create a small caloric deficit of roughly 500 calories per day (9, 10). “If calorie shifting helps you get there, go for it,” says Fernando.

Although, there are a few red flags. “The biggest safety concern is not getting at least the minimum required daily amount of macro and micronutrients for age and biological sex, which is necessary for optimal functioning body processes,” she advises.

Plus, metabolic confusion diet plans may not be ideal for those with diabetes. “Calorie shifting could dramatically affect blood sugar levels, which could be dangerous for people with diabetes,” warns Fernando. “It’s important to review with your doctor, especially if you are taking any medications for blood sugar management.”

How to Do It

Determine your calories

With metabolic confusion, the focus is on how many calories you consume, not the foods you eat. While calorie amounts vary, many metabolic confusion plans suggest limiting caloric intake to 1,200 on low-calorie days, and around 2,000 on “high”-calorie days. That’s… not much.

“Setting an arbitrary daily calorie intake goal ignores all the factors that go into determining individualized energy needs,” says Fernando. “This could severely under- or over-fuel your body, directly impeding weight loss results (11).” Rather, Fernando recommends a calculated, personalized approach.

Calorie needs shift with dieter differences such as age, sex, body size, and activity level but most adults need a minimum of 2,000 calories per day—more if you exercise (12). According to the USDA Dietary Guidelines for Americans, the average adult male needs 2,000 to 3,000 calories per day. “It’s important to note prolonged severe calorie restriction will make it more challenging to obtain all your macro and micronutrients in recommended amounts,” she warns. “Get it wrong and it could lead to malnutrition.”

She suggests working with a registered dietitian to get the calories (and macros and micros) right. “Indirect calorimetry is the gold standard for determining individual RMR and is what a registered dietitian (RD) will use to accurately determine your calorie needs,” says Fernando.

If working with an RD isn’t feasible, Fernando recommends at least using a calorie calculator to get a rough estimate of your needs.

Choose a format

You’ll then need to decide how often to switch between high- and low-calorie days. “The metabolic confusion diet does not provide any guidelines on the most effective format, and there’s very little research to suggest one schedule is more effective than another,” says Fernando.

The good news: this gives you the flexibility to choose what works best for you. Some plans switch every other week or month. Others (like Jimmy Kimmel) subscribe to an every few days format—similar to a 5:2 fasting schedule, where you eat normally for five days, then eat a significantly lower amount of calories for two days.

A big predictor of whether a diet is successful, per Fernando, is its long-term sustainability. That makes the flexibility of this eating pattern one of its biggest advantages.

Sample Metabolic Confusion Plan

The below plan is an example of how to assign high- and low- calorie days with a metabolic confusion diet. This sample plan is based on the middle range of calorie needs for adult men according to the USDA. We set normal calories at 2,500—which would be the high-calorie day. Then applied an approachable deficit of 500 calories a day to two to three days a week, bringing the low-calorie day down to 2,000 calories. 

Monday: Low-calorie day (2,000 calories)

Tuesday: High-calorie day (2,500 calories)

Wednesday: High-calorie day (2,500 calories)

Thursday: Low-calorie day (2,000 calories)

Friday: High-calorie day (2,500 calories)

Saturday: Low-calorie day (2,000 calories)

Sunday: High-calorie day (2,500 calories)

As with any diet, it’s important to listen to your body, and be willing to adjust the metabolic confusion diet as needed. Aside from swapping out the above with personalized calorie amounts based on your individual calorie needs, Fernando recommends focusing on quality, whole foods and getting a solid mix of macro and micronutrients to fuel your body with what it needs to perform. 

Pros of Metabolic Confusion

Here, a few reasons to give metabolic confusion a shot.

More mindful eating

“Tracking calories can help you become more familiar with how many calories are in one serving of your favorite foods—prepare to be surprised,” says Fernando. “After a while, you’ll become a pro in estimating how many calories are on your plate without the need for measuring cups or a food scale.”

While understanding calories is an important step to making healthier food choices, Fernando points out that it’s not the only factor. Your macro and micronutrients matter, too (more on that below).

Less hunger

Since the metabolic confusion diet is designed to increase calories in an intentional manner, Fernando notes you may avoid the feelings of deprivation and consequent cheat days that come hand-in-hand with many other low-calorie diets (13, 14).

Still, “whether you are calorie cycling or not, eating high volumes of ultra-processed foods high in added sugar, salt, and saturated fats will leave you craving more,” says Fernando. “The easiest way to fight hunger cravings is to aim for balanced meals and snacks with an adequate amount of protein, fiber, and healthy fats.”


“We are social creatures, and food plays a role in many social settings,” says Fernando. “The flexibility of the metabolic confusion diet allows you to still enjoy a meal at a family gathering, Sunday brunch, or birthday party—while avoiding the feelings of failure that often come with trying to stick to other restrictive diets.”

One of the main benefits of the metabolic confusion diet is that it doesn’t eliminate specific nutrients or foods you might save for special occasions. Studies show that the more flexible a diet is, the more likely you are to follow it in the long run (9, 10).

Cons of Metabolic Confusion

While there are some benefits to metabolic confusion, there are some drawbacks to consider.

It’s Restrictive

Metabolic confusion is more flexible and may lead to less cravings, but it’s still a calorie restriction diet. “Prolonged caloric restriction can lead to a poorer quality of life,” says Fernando. “You may find you have lower energy levels or micronutrient deficiencies without overt symptoms. That’s why it’s so important to work with a trained healthcare professional who can help you monitor your nutrition.”

Besides being tough to follow, studies show most restrictive diets fail to produce long-term weight loss results (9, 10, 15, 16). They also suggest you’re better off making sustainable healthy lifestyle changes like a modest calorie deficit through a nutritious diet, and exercise.

It Emphasizes Quantity Over Quality

The quality of your food matters. “A major downside to metabolic confusion is that it focuses on calories, regardless of where they come from,” explains Fernando. “An ultra-processed frozen dinner might be 300 calories whereas whole grain toast, two eggs, and half of an avocado is 350 calories. Less calories isn’t always the better choice.”

A diet high in ultra-processed foods puts you at a higher risk for early death (17). “Opt for lean protein like chicken, lean steak, and protein powder, healthy fats like olive oil, avocados, nuts, and seeds, whole grains, leafy greens, and fruits and vegetables,” she says.

It’s Unsustainable

“The best diet is an eating pattern that you are able to maintain through the rigors of daily life,” says Fernando. “If you can’t make it sustainable for you, it won’t be effective in the long run.” She encourages you to envision following a metabolic confusion diet every day for the rest of your life—is it feasible? If not, it’s not the diet for you.

Lack of research

The evidence that metabolic confusion actually works is slim. Even if it does gives you the flexibility, breaks, and satisfaction you need to get through spurts of caloric restriction, Fernando cautions more research is needed. The unknown safety and metabolic health implications of shifting calories might be worth giving metabolic confusion a pass for now (7).

It is still a diet and most fail to produce long-term results 

Although the metabolic confusion diet is more flexible than many other diets, it’s still a restrictive diet that’s designed for fast weight loss. 

Although most highly restrictive diets provide fast short-term weight loss results, those results don’t typically stick in the long run. An endless stream of research suggests a sustainable healthy lifestyle that encourages a modest calorie deficit by pairing a nutritious diet and increased exercise is your best bet for sustained weight loss (18, 19). 

Science-Backed Ways to Increase Metabolism

A reduced metabolic rate is a natural response to reduced calorie intake. Although this reduction is inevitable, there are a few ways to keep it moving.

Lift weights

The single most effective thing you can do to combat a drop in metabolism is strength training workouts. Weight loss naturally reduces metabolic rate and muscle mass (20), but muscle burns more calories at rest than fat. To increase fat loss, you want as much muscle as possible.

Regular strength training can help you maintain and build muscle mass, and is associated with a higher RMR (21, 22). This means, whether you opt for bodyweight training or pick up a heavy set of dumbbells, you give your metabolism a helping hand.

Prioritize protein intake

Regardless of which diet you choose or the severity of calorie restriction, it’s important to get enough protein. “To maintain and build muscle, I recommend at least 0.7 to 0.8 grams of protein per pound of body weight for those who engage in regular strength training,” says Fernando. “If it’s impossible to fit this much protein within your daily calorie limit, chances are your limit is too low.”

Studies show protein can help reduce appetite and cravings while boosting metabolism (23, 24, 25). One study published in Nutrition and Metabolism suggests that despite restricting calories, a keto diet high in protein and fat didn’t induce the expected dip in RMR, which researchers suspect was due to the preservation of lean muscle mass (26).

The Bottomline

Metabolic confusion may help you achieve a calorie deficit while enjoying more flexibility and less hunger, while avoiding the drop in basal metabolic rate (or the calories you naturally burn throughout the day at rest). However, there isn’t enough research to backup the metabolic confusion diet as safe and effective, especially long term. Talk to your healthcare provider to learn if the metabolic confusion diet is right for you. Or consider making lifestyle changes to achieve a slight calorie deficit like eating healthier foods and increasing physical activity—which has been shown to help with sustainable weight loss. 

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