If you've been following a low-calorie diet and splurged one day, you may be surprised to find that you didn't gain any weight. Some dieters do this on purpose. This is often called calorie cycling or calorie shifting, which involves alternating days of low-calorie intake with days of no diet restrictions. Can taking a break from dieting actually help you lose weight? Here's what you need to know about calorie cycling.
Introduction to Calorie Cycling
The zigzag diet, also known as calorie cycling or calorie shifting, is a dietary approach that involves varying your calorie intake on different days. Instead of sticking to the same number of calories every day, you alternate between higher-calorie and lower-calorie days. The idea behind calorie cycling is that occasional days of normal caloric intake can keep the body from thinking it's starving. As a result, your metabolism shouldn't be affected, even when you reduce your calories on most other days.
The Science Behind Calorie Cycling
Scientists believe that our bodies evolved to protect us from losing valuable calories and nutrients. In the past, lack of food was more common. Since a shortage of calories is a threat to survival, the body evolved to guard against weight loss. When food is scarce, your metabolism slows down, meaning you'll burn calories at a slower pace. So, when you go on a calorie-restricted diet, your body may think it's in danger of starvation. Your metabolism will slow down in response.
If you go on a low-calorie diet, you may lose weight at first. This can be a good motivator, but after a while, you may struggle to lose pounds. You may regain some weight, even if you've been careful about sticking to your low-calorie diet. A slowed-down metabolism may not correct itself. One study on the popular weight-loss TV show The Biggest Loser found that participants lost about 40% of their body weight, but also experienced a 23% reduction in their metabolic rate. Six years after they left the show, the participants gained an average of 90 pounds, but their metabolism remained slow.
How Calorie Cycling Works
Calorie cycling involves alternating between high-calorie and low-calorie days instead of eating the same amount daily. So instead of 1,800 calories every single day, you might do 1,400 on Monday, 2,200 on Tuesday, 1,500 on Wednesday, and so on. The weekly total still creates the calorie deficit you need for weight loss, you're just distributing it differently.
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Let's say you need 12,600 calories per week to lose weight (averaging 1,800 per day). You could split it like this:
- 4-5 lower days around 1,400-1,600 calories
- 2-3 higher days around 2,000-2,400 calories
The theory? When your body gets used to eating the same calories every day, your metabolism can slow down through something called adaptive thermogenesis. By varying your intake, you're supposedly keeping your metabolism from fully adapting.
Research on Calorie Cycling
In one study, one group followed a diet that included calorie cycling. They dieted for 11 days, then ate as they normally would for three days. The other group followed a strict calorie-restricted diet. At the end of the study, both groups lost the same amount of weight. Those who did calorie cycling saw no change in their metabolic rate and kept most of their weight off after the trial ended.
In another study, women spent a month on a low-calorie diet, followed by a month on a moderate diet. They repeated this pattern for five months. Their resting metabolic rate didn't fall, and they lost weight and body fat. They also exercised for three hours a week. It's unclear whether calorie cycling, the exercise, or the combination of both produced the positive results.
A study with 36 women found that zig zag dieting worked for weight loss, but wasn't more effective than regular dieting. Another study from the University of Western Australia found people who calorie cycled lost the same amount of weight and had the same metabolic rate as those on traditional diet.
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Potential Benefits of Calorie Cycling
Maintaining Metabolic Rate
The primary purported benefit of calorie cycling is preventing metabolic slowdown that can occur with consistent calorie restriction. The idea is that by having higher calorie days, you signal to your body that it's not in a starvation state, thus preventing a decrease in your resting metabolic rate (RMR).
Improved Adherence
Some individuals find calorie cycling easier to adhere to compared to traditional dieting. The flexibility of having higher calorie days can make the diet feel less restrictive, potentially reducing feelings of deprivation and making it more sustainable in the long term. People who tried calorie cycling reported feeling less hungry and had better mental clarity with less irritability.
Psychological Benefits
The ability to strategically plan higher calorie days around social events or cravings can reduce feelings of guilt and restriction. This can improve the overall psychological experience of dieting and make it more manageable.
Potential Hormonal Benefits
Leptin is a hormone that signals to the brain that you've eaten enough food. If you eat a larger meal than usual, your body increases its production of leptin for up to 24 hours. That means that you may feel satisfied longer. If you're doing calorie cycling, the leptin produced on your higher calorie days may keep you satisfied the next day.
Considerations and Potential Drawbacks
Lack of Standardized Approach
Another problem with testing calorie cycling is that there isn't a set way to do it. There are many different protocols and plans that involve various amounts of calories and days in which to restrict and not restrict.
Read also: Weight Loss with Low-FODMAP
Individual Variability
It's also important to take into account the many chemical and biological processes that affect weight loss. Here are three factors that could determine how well calorie cycling works.
- Exercise and Resting Metabolic Rate: Exercise could be more important than diet in determining your metabolic rate. When you exercise, you not only burn calories while you're working out, you also burn more when you're resting. About 60% to 75% of the calories you burn each day happens when you're resting. So, boosting your resting metabolism can significantly impact the total amount of calories you burn.
- Dopamine: After a good meal, your body releases the pleasure chemical known as dopamine. When you don't consume enough calories, you may find that you crave more food as your body seeks that pleasurable feeling. Exercise also releases dopamine, so being active could help you feel satisfied with a lower calorie meal.
Potential for Unhealthy Eating Habits
If high-calorie days are treated as "cheat days" with excessive consumption of unhealthy foods, it can negate the benefits of the diet and potentially lead to weight gain or other health issues. It’s important to remember that high-calorie days aren't "eat whatever" days. You still need mostly nutritious food. Don't go from 1,400 calories of chicken and vegetables to 2,500 calories of pizza and ice cream.
Not Suitable for Everyone
A zig zag diet may not be appropriate for everyone, particularly those with medical conditions that require consistent calorie intake, such as diabetes. As with any dietary approach, it's essential to consult a healthcare professional or registered dietitian before starting. Both methods work. Research shows continuous calorie restriction and calorie cycling are both effective, but people who cycle calories may experience better adherence and preserve more muscle.
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 may go up and down accordingly.
How to Set Up a Calorie Cycling Plan
If you're interested in trying calorie cycling, here's a step-by-step guide:
Calculate your Total Daily Energy Expenditure (TDEE) based on your age, weight, height, and activity level. For weight loss, you need a weekly deficit of 3,500-7,000 calories (1-2 pounds per week).
Get your weekly target. If you burn 2,000 calories daily (14,000 weekly) and want to lose 1 pound per week, you need a 500-calorie daily deficit. Weekly target: 10,500 calories (14,000 - 3,500)
Split it up. Most people do 4-5 low-calorie days and 2-3 high-calorie days per week. Using our 10,500 weekly example:
- Weekend approach: Monday-Friday: 1,300 calories (6,500 total); Saturday-Sunday: 2,000 calories (4,000 total)
- Workout-based approach: 3 training days: 1,800 calories (5,400 total); 4 rest days: 1,275 calories (5,100 total)
High and low days should typically vary by about 200-300 calories for less active people, with bigger differences if you're more active.
Track everything. Use MyFitnessPal, Lose It, or whatever app you like. You need to hit that weekly total. Individual days matter less than the overall average.
Give it time. Results typically show up after at least 4 weeks. Don't bail after a week and claim it doesn't work!
Common Mistakes to Avoid
- Treating high days like cheat days. High-calorie days aren't "eat whatever" days. You still need mostly nutritious food. Don't go from 1,400 calories of chicken and vegetables to 2,500 calories of pizza and ice cream.
- Going too low on low days. Don't go below 1,200 calories for women or 1,500 for men; that's not safe for most people. Keep low days reasonable.
- Not tracking the weekly total. You can't just wing it and hope your weekly average works out. Track consistently or this won't work.
- Ignoring protein. Hit your protein target every day, regardless of total calories. You need it to maintain muscle while losing fat.
- Giving up too soon. Give it at least a month before deciding if it's working. Weight loss isn't linear, especially with calorie cycling, where your daily weight will bounce around more.
Tailoring Calorie Cycling to Your Lifestyle
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Sample Week for Orange County Schedules
- Monday (Low - 1,400 cal): Greek yogurt, chicken salad, apple with almond butter, salmon with veggies
- Tuesday (Low - 1,400 cal): Protein smoothie, turkey wrap, cheese and carrots, tofu stir-fry
- Wednesday (High - 2,000 cal, Training Day): Eggs and toast, burrito bowl, protein bar, steak with sweet potato
- Thursday (Low - 1,400 cal): Oatmeal, tuna salad, Greek yogurt, chicken with quinoa
- Friday (High - 2,000 cal, Training Day): Pancakes, sandwich and soup, trail mix, pasta with meat sauce
- Saturday (High - 2,100 cal): Breakfast burrito, lunch out at Fashion Island, smoothie, pizza
- Sunday (Low - 1,500 cal): Protein shake, chicken rice bowl, veggies and hummus, baked fish
Your numbers will be different based on your size and goals. Work with our nutrition coaches to figure out your specific targets.
Calorie Cycling vs. Other Dieting Approaches
Calorie Cycling vs. Traditional Dieting
Studies show both approaches lead to similar weight loss; calorie cycling doesn't make you lose MORE weight than traditional dieting. The real benefit is that you might actually stick with it longer. The advantage is that some people find it easier to stick with long-term because it feels less restrictive. Studies found people who calorie cycled reported less hunger and better mental focus. But if regular dieting works for you, there's no reason to switch.
Calorie Cycling vs. Yo-Yo Dieting
Not to be confused with yo-yo dieting, zig zag dieting is very different. Zig zag dieting involves altering your calorie intake from day to day. Yo-yo dieting involves going through weight changes. Basically, yo-yo dieting is the term for people who do an aggressive diet in the summer time in order to lose a ton of weight (the yo-yo going down). Then, when that beach party is over, eating in a surplus again and gaining that weight back (the yo-yo going up). This has been shown to be damaging to your metabolism which can make it harder to lose weight over time. Luckily, calorie cycling involves more short term diet changes with the goal of getting weight down and keeping it off, rather than intentionally fluctuating weight. Thus, it doesn’t carry the same metabolic harm that yo-yo dieting can cause.
Calorie Cycling vs. Carb Cycling
If you’ve heard of carb cycling, this zig zag thing may sound familiar. However, though very similar, carb cycling is not the same as calorie cycling. Carb cycling is another weight loss method that people use that involves eating high amounts of carbs some days and then eating low carb on other days. For the same reasons that we noted with calorie cycling, it’s not more effective at causing fat loss because, again the weekly average is what matters in the diet rather than the day to day consumption. However, calorie cycling involves altering intake from all macronutrients: protein, fat and carbohydrate, making it slightly different from carb cycling.