Blog Diets Zig Zag Diet: Is This The Solution For Restrictive Fad Diets?

Zig Zag Diet: Is This The Solution For Restrictive Fad Diets?

Calorie restriction is out, and the zig zag diet (aka calorie shifting, aka metabolic confusion diet) is in. Don’t let the negative connotations of its names fool you—this is a much healthier way to diet than traditional calorie restriction. Over the years, researchers have looked into why sticking to a restrictive diet with a set caloric goal can lead to weight gain or plateauing after just a few weeks.


As it turns out, when your body gets used to a set caloric intake, it starts to burn fewer calories overall. That means if you’re stuck eating the same amount of calories each day, your body will eventually catch up, and you’ll end up gaining weight or plateauing.

This isn’t a modern-day phenomenon. When hunter-gatherers were faced with periods of starvation, their bodies would adapt in order to conserve energy and go into a sort of metabolic hibernation mode. So your diet failing isn’t you being lazy—it’s science (5).

Enter the zig zag diet, which takes advantage of this metabolic flexibility. It makes you live exactly how the cavemen did—eat one day, feast the next. That means you’re constantly switching things up so your body never gets used to a set caloric intake. 

Does this approach work? Let’s take a look.

What Exactly Is A Zig Zag Diet?

As its name suggests, the zig zag diet is a way of eating that changes its calorie intake every few days. 

This means you could have a day where you eat around 2000 calories, followed by a day where you consume 1500–1800 calories, and then a third day where you eat up to 2500 calories.

The idea is that by constantly shifting your caloric intake, you avoid some of the biological responses that lead to weight gain and plateauing. This approach should keep your metabolism on its toes so it’s constantly burning calories efficiently. 

On top of that, the zig zag diet also allows for some variety in your meals, which can make it easier to stay on track.

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zig zag diet

Does Zig Zag Diet Work?

Studies on the effectiveness of the zig zag diet are still limited, but the few that have been conducted suggest that it may be a viable option

We should mention that study size, duration, and design can vary greatly from one paper to the next, making it hard to draw definite conclusions.

In one study, 3 weeks of a restrictive, low-calorie diet followed by a week of higher-calorie eating resulted in an increase in metabolic rate (14). 

At first, the participants’ metabolic rates fell (which is what often happens when we restrict calories), but at the end of the study, their metabolic rates not only returned to the baseline levels but surpassed them (14).

In another study, participants who had been lifting weights followed a calorie-restricted diet followed by a 2-day higher carb and calorie “refeed” period (9). 

At the end of the 7-week study, the participants had preserved their muscles and achieved higher resting metabolic rates than they had before the experiment. This hints that zig zag dieting may prevent the metabolic slowdown associated with strict dieting (9)

However, some studies haven’t found a significant difference in weight loss or metabolism between zig zag dieters and calorie-restricted dieters (8) (10). This could be due to several factors, including the participants’ commitment level, the duration of the study, or a lack of consistency.

More research is needed to understand the effects of a zig-zag diet. Until then, it’s hard to say definitively whether this approach is better than traditional dieting for weight loss.

That said, a look into the scientifically proven metabolic adaptations to calorie-restricted diets may provide more insight into the efficacy of a zig-zag diet.

zig zag diet

What Causes Calorie-Restricted Diets To Fail In The Long Term?

When you restrict calories for an extended period, your body will eventually adapt in order to conserve energy. This is called metabolic adaptation (13). Some of the changes that happen when you’ve been on a low-calorie diet for a long time include:

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Decrease In Testosterone

Studies have shown that calorie-restricted diets can lead to a significant drop in testosterone levels, which may affect your ability to build and maintain muscle (11).

Adaptive Thermogenesis

Also called “starvation mode”, this is when your body decreases its energy expenditure in response to a decrease in calorie intake (2).

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Decrease In Physical Activity

To further conserve energy, your body may reduce the amount of physical activity you do. You’ll find yourself feeling exhausted and lacking the motivation to exercise.

Decrease In Thyroid Hormone

Studies have linked low-calorie diets to decreased levels of thyroid hormone, which may further slow your metabolism (20).

Decrease In Leptin

Leptin is a hormone produced by fat cells that helps regulate appetite (16). Studies have shown that calorie-restricted diets lead to decreased leptin levels, which can cause intense cravings and make it difficult to stay on track (19).

Increase In Cortisol

Cortisol is the “stress hormone” and high levels can lead to increased fat storage, especially in the abdominal area. It’s also linked to increased cravings and decreased energy levels (18).

Increase In Ghrelin

Ghrelin is the “hunger hormone” and calorie restriction can increase levels of this hormone, leading to increased hunger and cravings (1) (7).

These metabolic adaptations can have a significant impact on your ability to lose weight and keep it off. 

Without the proper nutrients and support, it can be challenging to maintain a caloric deficit long-term. That’s why even when you lose some weight through calorie restriction it can often be hard to keep the weight off in the long run.

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Does Zig-Zag Dieting Help Avoid Metabolic Adaptation?

When you alternate between calorie-restricted and refeed days, you’re providing your body with the energy it needs to stay active and maintain muscle. 

Essentially, you’re “tricking” your body into thinking it’s not in a calorie deficit, which can prevent or reduce the metabolic adaptations associated with strict dieting.

Think about how the hunter-gatherers lived. They would alternate between periods of feast and famine, never really going into an extended calorie deficit. This allowed them to stay active and maintain muscle while still getting the energy they needed (5). 

In theory, a zig-zag diet should be able to provide you with the same benefits without having to go through the same extreme fluctuations in calorie intake. 

If you can maintain a caloric deficit while still providing your body with enough energy to function, then the metabolic adaptations associated with calorie-restricted diets may be avoided or reduced. 

The Benefits Of Zig Zag Dieting

The zig-zag diet is a great way to:

Maintain A Long Term Calorie Deficit

Diets like keto are often criticized for being difficult to stick with long-term due to their restrictive nature (3). A lifetime of eating this way is usually not sustainable. 

The zig-zag diet allows you to maintain a caloric deficit without feeling overly restricted or deprived. As it doesn’t limit what you eat provided you stay in a deficit, it’s a much more sustainable approach for the long term.

Preserve Muscle Mass

When you’re on an overly restrictive diet, your body will often begin to break down muscle for energy (17). This can be prevented by providing your body with enough energy and nutrients to function properly. 

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The zig-zag diet helps you to do this, allowing you to maintain muscle mass while still losing fat.

Prevent Metabolic Adaptations

By alternating between calorie-restricted and refeed days, you can avoid the metabolic adaptations associated with strict dieting (4). 

As your body never goes into an extended deficit, it never has to slow its metabolism or rely on other adaptive strategies. This will keep you from hitting a weight-loss plateau and ensure you see steady and consistent results.

zig zag diet

The Drawbacks Of Zig-Zag Dieting

Like most diets, the zig-zag diet has its drawbacks. 

Doesn’t Emphasize Food Quality

The zig-zag diet does not emphasize food quality. As long as you stay in a deficit, you can eat whatever you want on your refeed days. This may encourage unhealthy eating habits and a lack of nutritional focus. Remember, there’s more to your overall health than just losing weight.

Can Cause Unwanted Weight Fluctuations

Due to the nature of this diet, you’re likely to experience some unwanted weight fluctuations. As you alternate between a deficit and refeed days, your weight will go up and down accordingly. This can be discouraging if you’re looking for consistent, long-term results.

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It’s Time Consuming

The zig-zag diet requires a lot of planning and organization. 

You’ll need to make sure that you’re eating the proper amount of calories on your refeed days, and that you’re alternating between high-calorie and low-calorie days. This can be time-consuming and inconvenient, especially if you’re already busy with other commitments. 

May Trigger Binge Eating And Other Unhealthy Habits

The zig-zag diet can make it difficult to differentiate between a refeed day and an unhealthy binge. You may be tempted to go overboard when it comes to your refeed days, leading to feelings of guilt and shame. 

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zig zag diet

How To Get Started With The Zig-Zag Diet

If you decide to try the zig-zag diet, here are some tips for getting started:

Determine Your Calorie Needs

The first step is to determine how many calories you need per day. You can use a calorie calculator to do this. 

Once you know your daily caloric needs, you can then decide how many calories to eat on each refeed day. A sustainable deficit would be around 500-750 calories per day (6). 

Choose Healthy Foods

Along with the calorie content of foods, consider their nutritional value (15). Aim to fill your diet with nutrient-dense foods like fruits, vegetables, lean proteins, and whole grains on both high and low-calorie days.

Plan Ahead

Spend some time planning and organizing your meals for the week. This will make it much easier to stay on track and avoid unhealthy foods (12).

Be Flexible

Don’t set rigid rules for yourself. If a refeed day doesn’t go as planned, don’t beat yourself up. Just get back on track the next day and keep going.

The Bottom Line

The zig-zag diet can be an effective and sustainable way to lose weight. By alternating between calorie-restricted days and refeed days, you can prevent metabolic adaptations and maintain muscle mass while losing fat. 

However, it’s important to remember that food quality matters and that the zig-zag diet may not be right for everyone. Before beginning this or any other diet, consult with your doctor to ensure it is safe and healthy for you.



This article is intended for general informational purposes only and does not address individual circumstances. It is not a substitute for professional advice or help and should not be relied on to make decisions of any kind. Any action you take upon the information presented in this article is strictly at your own risk and responsibility!


  1. Adaptations of leptin, ghrelin or insulin during weight loss as predictors of weight regain: a review of current literature (2013,
  2. Adaptive thermogenesis in humans (2010,
  3. Advantages and Disadvantages of the Ketogenic Diet: A Review Article (2020,
  4. Calorie Shifting Diet Versus Calorie Restriction Diet: A Comparative Clinical Trial Study (2014,
  5. Current views on hunter‐gatherer nutrition and the evolution of the human diet (2017,
  6. Defining the Optimal Dietary Approach for Safe, Effective and Sustainable Weight Loss in Overweight and Obese Adults (2018,
  7. Ghrelin: much more than a hunger hormone (2014,
  8. Impact of intermittent energy restriction on anthropometric outcomes and intermediate disease markers in patients with overweight and obesity: systematic review and meta-analyses (2021,
  9. Intermittent Energy Restriction Attenuates the Loss of Fat Free Mass in Resistance Trained Individuals. A Randomized Controlled Trial (2020,
  10. Intermittent versus continuous energy restriction on weight loss and cardiometabolic outcomes: a systematic review and meta-analysis of randomized controlled trials (2018,
  11. Long‐term effects of calorie restriction on serum sex‐hormone concentrations in men (2010,
  12. Meal planning is associated with food variety, diet quality and body weight status in a large sample of French adults (2017,
  13. Metabolic adaptations to weight loss (2019,
  14. Metabolic adaptation to caloric restriction and subsequent refeeding: the Minnesota Starvation Experiment revisited (2015,
  15. Optimal Diet Strategies for Weight Loss and Weight Loss Maintenance (2021,
  16. Physiology, Leptin (2022,
  17. Preserving Healthy Muscle during Weight Loss (2017,
  18. Stress and Obesity: Are There More Susceptible Individuals? (2018,
  19. The ups and downs of caloric restriction and fasting: from molecular effects to clinical application (2021,
  20. Thyroid Hormone Regulation of Metabolism (2014,
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