This Diet Claims To 'Trick' Your Metabolism Into Working Harder—But Is It Safe?
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In the world of weight loss, your metabolism is a major player. This complex process helps convert your food into energy and dictates how many calories you burn just by existing. With that, it makes sense to want to tap into your metabolism’s powers for weight loss. Enter metabolic confusion, an eating pattern that involves switching between high-calorie and low-calorie days to "trick" your metabolism into working harder.
Metabolic confusion, a colloquial term for the concept of calorie shifting, is designed to rev up your metabolism, with the end goal of helping it to burn as many calories as possible at baseline. In theory (note the italics), this would allow you to lose weight at a faster pace than if you didn’t do metabolic confusion. However, it's not as simple (or safe) as it may seem. Experts say that the restrictive diet can be hard to follow, and, honestly, might leave you feeling hungrier than you’d like.
So, is metabolic confusion worth your time and energy, or is it another potentially harmful weight loss trend you should ignore? Registered dietitians break it down.
Meet the experts: Scott Keatley, RD, is a dietitian and the co-owner of Keatley Medical Nutrition Therapy. Jessica Cording, RD, is a dietitian and the author of The Little Book of Game-Changers. Keri Gans, RD, a New York City-based nutritionist and the author of The Small Change Diet.
What is metabolic confusion?
Metabolic confusion, also known as calorie shifting or calorie cycling, involves alternating between high-calorie and low-calorie days or periods of time, says dietitian Jessica Cording, RD, author of The Little Book of Game-Changers. Although its exact origins are unclear, calorie shifting could have evolutionary roots since hunter-gatherers may have had a similar eating pattern since food wasn't always consistently available.
There are many ways to implement the strategy—for example, you may opt for a high-calorie day followed by a low-calorie day, or have an entire week of high-calorie days before having another week of low-calorie days (or somewhere in between).
The theory is that, by varying your caloric intake, you confuse your body (and metabolism), encouraging it to burn more energy than if you just stayed at the same calorie intake each day. “It’s about being in calorie deficit most of the time,” Cording says. “The name is kind of misleading. You're not 'tricking' your metabolism—you're just staying in a calorie deficit.”
The exact number of calories you can have during "low" and "high" days can vary. That said, many programs online recommend having around 2,000 calories or so on high days, and no more than 1,200 calories on low days, Cording says.
Benefits Of Metabolic Confusion
A big perk of metabolic confusion is that you can have flexible calorie goals that you can adapt to your activity levels and have the ability to mix things up, says Scott Keatley, RD, co-owner of Keatley Medical Nutrition Therapy. “This flexibility could help people stick to their diets better [and] reduce the temptation to overindulge,” he says. “Additionally, by allowing higher calorie intake on certain days, individuals may find it easier to engage in social activities without feeling deprived.”
Metabolic confusion may also offer a slightly more sustainable alternative to pure restriction 24/7. “Part of why people find this approach helpful is [because] it gives you more flexibility and breaks from very restrictive eating, but you're still in a calorie deficit,” Cording says.
Risks Of Metabolic Confusion
As with any diet plan, there are a few potential risks to keep in mind. "[Metabolic confusion] is still a form of calorie restriction, which can be challenging to maintain over time,” Keatley says. Alternating between high and low-calorie days also “might lead to nutritional imbalances or deficiencies if not carefully managed," he says.
Additionally, restricting your food intake can raise the risk of disordered eating behaviors, says Keri Gans, RD, a New York City-based nutritionist and the author of The Small Change Diet. This can often look like binge-eating on high-calorie days and being overly restrictive on low-calorie days, she says.
“Something I have seen is people eating 1,200 calories on some days and then eating ‘anything you want’ on other days,” Cording says. “That sets people up for a 'feast or famine' mindset, which is not helpful for long-term health.”
On low-calorie days, you may also end up feeling wiped out, dizzy, and nauseous, Gans says, which you definitely want to avoid. And of course, for many, constantly shifting your calorie intake can be stressful itself. This aspect alone can negatively impact your relationship with food, Keatley says.
Does metabolic confusion work for weight loss?
Although it might sound promising as an easy hack to boost your metabolism, metabolic confusion isn’t a slam dunk for weight loss, nutritionists say. “The body doesn't operate in a way that can be ‘confused’ by such changes,” Keatley says. A consistent calorie deficit through diet and exercise often yields the same results, he adds. Plus, whether or not you can actually "trick" your metabolism is still not conclusively confirmed through scientific studies, Gans says.
There is some research about metabolic confusion—results have just been mixed. One study found that people who restricted their calorie intake for 11 days then ate whatever they wanted for three days had a drop in their resting metabolic rate (the number of calories your body burns at rest) at the end of the study. Meanwhile, participants in the "metabolic confusion" group had the same resting metabolic rate as when they started. People on the metabolic confusion diet lost more weight and were also less hungry than the traditional calorie restrictors.
However, another study of 100 participants published in JAMA Internal Medicine found that there was no major difference in weight loss between people who did a typical calorie restrictive diet and a metabolic confusion diet.
Ultimately, you can see the number on the scale go down when trying metabolic confusion, but it’s for all the same reasons why any calorie-restricting diet can help you lose weight, Keatley says. “While varying calorie intake might offer short-term weight loss, sustainable results usually require more consistent and balanced dietary approaches,” he says.
How To Try Metabolic Confusion Safely
To be clear, dietitians are not overly excited about the metabolic confusion diet. “I would recommend focusing on eating a well-balanced, plant-forward diet, getting plenty of physical activity, and adequate sleep on a weekly basis,” Gans says.
But if you really want to try the metabolic confusion strategy, Cording recommends making sure that you’re still eating a varied diet while alternating your calorie intake. “You still need to cover your nutrient bases,” she says. “If you lose too much muscle, it can be easier to regain weight.”
If you're a high-performance athlete or you're simply interested in crunching the numbers, it may be helpful in some cases to figure out your calorie requirements or use a nutritional database or app to design meals that meet your targets, Keatley says. “Avoid exceeding or falling below your calorie goal by more than 500 calories to minimize muscle loss and fat gain risks,” he recommends.
Keep in mind that calorie restriction isn't recommended and that tracking your calories isn't always the healthiest strategy for everyone—especially if you have a history of disordered eating or a diagnosed eating disorder. Options like the Mediterranean Diet, Whole30, and other less-restrictive eating plans can offer a safer alternative to cutting calories. If you're able, consider meeting with a registered dietitian for personalized advice on how to craft a sustainable and healthy weight loss plan for you.
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