How does the metabolic diet plan 13-day eating plan measure up as a weight loss plan? Can it help you lose weight as advertised, or is it just another popular fad diet that causes more harm than good?
When it comes to finding the best diets for weight loss, it’s always easier said than done. With dozens of eating plans that all claim to be the best fat loss diet available, determining what will work for you can be a headache, particularly as most of us don’t have the time or resources to try every diet that’s out there just to find the perfect one.
To help you narrow down the list of potential weight loss diet plans, we’re going to break down the 13-day metabolic diet plan and tell you if it’s worth your time or not.
What Is the Metabolic Diet Plan 13-Day Weight Loss Diet?
Also known as the 13-day diet, 13-day metabolism diet, Copenhagen diet, or the Royal Danish Hospital Diet, this is a 13-day eating plan that promises to help people lose up to 22 lbs (approximately 10 kg) in just under two weeks.
For anyone who wants to better understand this meal plan, here are some things you should keep in mind, as well as some rules that should be followed:
- It’s very low in calories. All the food that’s eaten in a day comes to approximately 600 calories.
- While on this metabolic diet, you’re required to consume 2 liters of water a day.
- There are little to no carbohydrates in this diet. The so-called metabolic meals on this eating plan are high in protein and low in fats. The metabolic diet plan 13-day sample menu below will show you that the weight loss diet will make you eat animal-based protein, lots of vegetables, some fats, and the occasional carbohydrate.
- Some variations of the diet call for no salt, but allow for the use of other spices such as garlic and pepper.
- Some other restrictions on this diet include no chewing gum, no alcohol, no cooking oil, no salad dressing, and no sweeteners such as sugar and honey. Any other food that’s not listed on the metabolism diet plan should also be avoided.
- The creators of this diet also state that anyone who can successfully complete all 13 days of the diet shouldn’t try it again for another two years. Those who fail to strictly follow the diet and cheat or fall off the wagon can try again, but only after six months.
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What Do Metabolic Meals on the Copenhagen Diet Plan Look Like?
As previously stated, this metabolic weight loss diet plan is for a total of 13 days. However, we won’t be listing all the meals for 13 days. Instead, we’ll give you a two-day sample of the most popular metabolic diet plan 13-day variations. This will help paint a picture of what your daily meals would look like:
Day 1
- Breakfast – 1 cup of coffee sweetened with 1 sugar cube
- Lunch – 400g cooked spinach, 2 hard-boiled eggs, and 1 tomato
- Dinner – 200g grilled steak with a side of green salad. Dress the salad with some lime, but remember, no oil is allowed
Day 2
- Breakfast – 1 cup of coffee sweetened with 1 sugar cube
- Lunch – 200 to 250g of ham with 1 cup of low-fat yogurt
- Dinner – 200g of roast beef with a side of green salad dressed with some lime or lemon juice
As you can see, these meals are quite small and the servings aren’t nearly enough to keep a grown adult, male or female, full.
According to the Dietary Guidelines for Americans 2020 – 2025, the estimated calorie needs range from 1,600 to 2,400 calories per day for females and 2,000 to 3,000 calories per day for males (1).
Taking this into consideration, it can be seen that the metabolic diet plan 13-day meals are far below what’s considered healthy and fulfilling.
How to Lose Fat Fast: Is the Metabolic Diet Plan 13-Day Eating Program the Answer?
No, it’s not. Despite what this eating plan claims, it won’t help you lose almost 22 pounds in 13 days. Here are 2 main reasons why this diet won’t work:
The Eating Plan Is Too Low in Calories
This is basically a starvation diet that will potentially only lead to the loss of water weight and not actual fat. The hard truth is that sustainable 2-week weight loss is somewhere between 2 to 4 pounds. Any diet that promises anything more than this is a fad diet that should be ignored and never attempted.
In addition to its claims for weight loss being absolutely not based on scientific fact, this diet can actually slow down your metabolism instead of revving it up as it promises. Research has shown that severely restricting your calorie intake can slow down your metabolic rate, which means that your body ends up burning calories more slowly than it already was (2, 3, 4). When your metabolism slows down, this means that most of the food you consume doesn’t get turned into energy and used up but gets stored as fat in the body, which leads to fat and weight gain.
The Diet Doesn’t Advocate for Exercise
It’s no secret that you can lose weight without necessarily having to exercise. In fact, research has shown that an energy deficit, specifically one that is tailored to the individual, is one of the most important factors in weight loss (5). Basically, as long as you eat following a healthy and nutritionally balanced calorie deficit, the pounds will fall off (6).
However, even while losing weight through diet alone is a possibility, studies have shown that a combination of a good and healthy calorie deficit diet plus exercise is one of the best ways to lose weight (7).
The CDC recommends that adults need (8)
- At least 150 minutes a week of moderate-intensity aerobic activity or 75 minutes of vigorous-intensity aerobic activity
- At least 2 days a week of muscle-strengthening activity
This is the bare minimum every adult needs to do to lead a healthy life, regardless of their weight goals. They also add that if you’re looking to shed some weight, then adjusting your diet and perhaps doing more than the recommended amounts above can help you reach your goals (8).
To summarize, this diet will fail to give you the promised weight loss results because:
- The calories consumed are too little for an adult and will likely slow down your metabolic rate
- The diet doesn’t encourage exercise that helps burn calories, so it increases the chances of weight loss success. It should be noted that even if you choose to exercise while following the diet, the calories provided are still too little and you’ll find it incredibly difficult to push through an entire workout session.
Read more: 24 Weight Loss Smoothies, 2 Diet Plans, and 5 Belly Fat Smoothie Secrets
How Much Weight Can You Lose on a 13-Day Diet?
A healthy 13-day diet that combines both exercise and calorie deficit meals can help you lose approximately 2 to 4 pounds. This is in accordance with the Centers for Disease Control and Prevention guidelines that state that healthy and sustainable weight loss generally means a loss of 1 to 2 pounds a week (9).
What Is a Metabolic Confusion Meal Plan?
This is another fad diet that promises to help you lose a large amount of weight by tricking or confusing your metabolism. The diet takes tips from the 5:2 intermittent diet plan where it alternates between high-calorie and low-calorie days.
However, unlike the 5:2 diet that calls for no more than 500-600 calories for women and 600-800 calories for men on fasting days, this confusion meal plan states that on low-intake days, you shouldn’t consume more than 1,200 calories, and on high-intake days, you can consume 2,000 calories or more if you so choose.
Proponents of this meal plan claim that by switching or cycling between high- and low-calorie intakes, your metabolism will be forced to work harder, thereby burning more calories and resulting in weight loss.
But can this diet improve your metabolic rate and boost weight loss? The answer seemingly depends on who you ask as research on the notion of calorie cycling varies.
For example, in 2014, a study by the International Journal of Preventive Medicine showed that calorie cycling, like the one followed by the metabolic confusion meal plan, could have positive results (10).
Researchers took 74 subjects and divided them into two groups: one group only consumed 1,200 calories per day, while the other had their calories restricted for 11 days followed by three (3) days of unrestricted food energy intake. After four (4) weeks, researchers found that the calorie cycling group lost more weight, experienced less hunger and increased satisfaction from food, and had a significant decrease in blood sugar, total cholesterol, and triacylglycerol, in comparison to the calorie restriction group.
However, it’s important to note that despite all these positive changes, their metabolic rate remained the same (10).
Despite these promising results in the 2014 study, a 2018 study yielded quite different results (11). This 4-year long study followed 100 participants who were divided into three (3) groups
- Calorie restriction – 75% of energy needs every day
- Alternate-day fasting – 25% of energy needs on fast days; 125% of energy needs on alternating “feast days”
- No-intervention control
At the end of the study, researchers found no significant differences in weight loss between people who followed a calorie-shifting diet and those who adhered to traditional calorie restriction (11).
Due to research on calorie cycling differing significantly, we suggest that you should stick to the 5:2 diet and follow its guidelines instead of following a metabolic confusion diet for weight loss. Research on weight loss using the 5:2 diet has remained consistent in demonstrating that it can help with fat loss, weight loss, and general weight management (11, 12).
Check out our other article on fasting for 3 days to see if this is a viable weight loss and metabolism-boosting option for you.
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What Is the Fast Metabolism Diet?
This meal plan is essentially the same as the metabolic diet plan for 13 days. However, instead of promising a loss of 20 plus pounds in less than 2 weeks, it promises a loss of 20 pounds in 28 days.
It also calls for the elimination of foods such as wheat, corn, dairy, soy, refined sugar, and caffeine. While removing refined sugar is ultimately good for your health (13), removing the rest of these foods can cause more harm than good.
Research has shown that removing entire food groups from your diet or different foods from a normal diet can lead to nutritional deficiencies in both healthy subjects and people suffering from allergies and other health issues (14, 15, 16).
Read more: Your Guide To The 7-Day Protein Diet Plan for Weight Loss
FAQs
How can I get a fast metabolism?
As shown above, this diet isn’t the answer to getting a fast metabolism. However, not all hope is lost. As metabolism plays a significant role in weight loss and gain, learning how to increase it can help you burn calories faster.
Some natural ways to boost your metabolism include drinking more water, working out more, not skipping meals, not severely restricting your diet, and eating foods that will boost your metabolism.
Can I lose belly fat in 13 days?
No, you can’t lose belly fat in just 13 days. As with any other fat in the body, losing belly fat takes time, patience, exercise, and a healthy calorie deficit diet.
If you have an endomorph body type, check out our article on the endomorph meal plan to learn the best dietary tips to help you reach your ideal weight goals.
Can I lose 20 lbs in 13 days?
No, you can’t. If you want to lose 20 lbs, it’s best to increase your timeline to two and a half to five months and aim for a weight loss rate of 1 to 2 pounds per week.
What foods speed up the female metabolism?
Some foods that can boost your metabolism include:
- Protein-rich foods – These include options such as lean meats, fatty fish, eggs, dairy, beans and legumes, nuts, and seeds
- Products with caffeine such as tea and coffee
- Water
- Ginger
- Chili peppers
Can I drink coffee on the fast metabolism diet?
Yes, coffee is allowed on the fast metabolism diet. However, as demonstrated above, this diet isn’t the best or healthiest for weight loss, so we recommend that you don’t indulge in it. However, you can still drink coffee as part of a healthy diet as research has shown that catechins – which are found in both coffee and tea – have some metabolism-boosting benefits (17, 18).
The Bottom Line
No, you shouldn’t. While we agree that weight loss is difficult and understand the desire to see fast results, we can’t recommend this eating plan to you in good faith. Not only is this a fad diet that promises unachievable results, it’s also extremely low in calories and lacking in nutrients and could land you in hospital.
If you’re looking to change your diet to lose weight, please consult your doctor or dietitian to help determine what’s the best diet for weight loss for you – a diet that won’t jeopardize your health.
DISCLAIMER:
This article is intended for general informational purposes only and does not serve to address individual circumstances. It is not a substitute for professional advice or help and should not be relied on for making any kind of decision-making. Any action taken as a direct or indirect result of the information in this article is entirely at your own risk and is your sole responsibility.
BetterMe, its content staff, and its medical advisors accept no responsibility for inaccuracies, errors, misstatements, inconsistencies, or omissions and specifically disclaim any liability, loss or risk, personal, professional or otherwise, which may be incurred as a consequence, directly or indirectly, of the use and/or application of any content.
You should always seek the advice of your physician or other qualified health provider with any questions you may have regarding a medical condition or your specific situation. Never disregard professional medical advice or delay seeking it because of BetterMe content. If you suspect or think you may have a medical emergency, call your doctor.
SOURCES
- Dietary Guidelines for Americans 2020 – 2025 (n.d., dietaryguidelines.gov)
- Adaptive thermogenesis in humans (2013, ncbi.nlm.nih.gov)
- Adaptive thermogenesis with weight loss in humans (2013, pubmed.ncbi.nlm.nih.gov)
- Persistent metabolic adaptation 6 years after “The Biggest Loser” competition (2016, pubmed.ncbi.nlm.nih.gov)
- Optimal Diet Strategies for Weight Loss and Weight Loss Maintenance (2020, ncbi.nlm.nih.gov)
- Weight-Loss and Maintenance Strategies (n.d., ncbi.nlm.nih.gov)
- Diet, exercise or diet with exercise: comparing the effectiveness of treatment options for weight-loss and changes in fitness for adults (18–65 years old) who are overfat, or obese; systematic review and meta-analysis (2015, ncbi.nlm.nih.gov)
- Physical Activity and Your Weight and Health (2023, cdc.gov)
- Steps for Losing Weight (2023, cdc.gov)
- Calorie Shifting Diet Versus Calorie Restriction Diet: A Comparative Clinical Trial Study (2014, ncbi.nlm.nih.gov)
- A randomised controlled trial of the 5:2 diet (2021, ncbi.nlm.nih.gov)
- Effects of an Intermittent Fasting 5:2 Plus Program on Body Weight in Chinese Adults with Overweight or Obesity: A Pilot Study (2022, ncbi.nlm.nih.gov)
- The Impact of Free Sugar on Human Health—A Narrative Review (2023, ncbi.nlm.nih.gov)
- Food Elimination Diet and Nutritional Deficiency in Patients with Inflammatory Bowel Disease (2018, pubmed.ncbi.nlm.nih.gov)
- The effects of elimination diet on nutritional status in subjects with atopic dermatitis (2013, ncbi.nlm.nih.gov)
- Elimination Diet (n.d., sciencedirect.com)
- The effect of caffeine on energy balance (2017, pubmed.ncbi.nlm.nih.gov)
- Effect of Acute and Chronic Dietary Supplementation with Green Tea Catechins on Resting Metabolic Rate, Energy Expenditure and Respiratory Quotient: A Systematic Review (2021, ncbi.nlm.nih.gov)