Why You Shouldn't Try the 3-Day 'Mayo Clinic' Diet

Despite its name, the 3-Day Mayo Clinic Diet did not originate with, nor was it ever endorsed by, the renowned Mayo Clinic. It's just another fad diet that touts speedy weight loss — up to 10 pounds in three days.

The Mayo Clinic name is wrongfully associated with several types of fad diets that promise quick weight loss in a short time, like the Grapefruit Diet and the Cabbage Soup Diet. While these diets may include some healthy foods, they are not healthy or sustainable options for weight loss.

"These fad diets did not originate from the Mayo Clinic as they do not meet the Mayo Clinic's principles. We believe that the (real) Mayo Clinic Diet isn't even a diet — it's a lifestyle approach that warrants behavioral changes for long-term sustainability," Katherine Zeratsky, RD, LD, a dietitian with the Mayo Clinic, tells LIVESTRONG.com.

Read more: 4 Types of Diets to Avoid if Long-Term Weight Loss Is Your Goal

The 3-Day Mayo Clinic Diet — sometimes called the 3-Day Diet or The Military Diet — promises that you can lose 6 to 10 pounds in three days. How? It's a very low-calorie menu that involves eating fruits, vegetables and protein with few carbohydrates or fats, and lots of water.

For example, breakfast each day consists of a carbohydrate and protein, such as toast with peanut butter, a piece of cheese or an egg. Lunch involves much of the same kind of combo, such as bread with tuna or cottage cheese. A sample dinner might include a small serving of skinless chicken, 1 cup of broccoli, 1 cup of asparagus, 1 piece of fruit and a half cup of vanilla ice cream.

As a rule of thumb, losing 1 to 2 pounds a week is the safest way to slim down. A low-calorie fad diet like the 3-Day Mayo Clinic Diet or the Grapefruit Diet will only cause short-term weight loss, as these eating plans mostly cause a loss of water and muscle mass, not fat loss, according to the American Academy of Family Physicians.

The 3-Day Diet is so food-restrictive it would be difficult to stay on it long-term. And there's a very good chance a dieter will gain back the weight he or she lost, and possibly more.

Read more: The Best Tips for Every Stage of Your Weight-Loss Journey

"When diets are so restrictive, not only will they cause nutrient deficiencies, but they're also not sustainable. If a diet promises something that's too good to be true, chances are you won't be able to maintain the weight loss," says Zeratsky.

Following a high-protein, low-carb diet long-term not only results in nutrient deficiencies but also other negative side effects. The Mayo Clinic warns that high protein consumption can lead to bad breath, headache and constipation. What's more, some high-protein diets, when they include foods like red meat and full-fat dairy, may boost the risk of heart disease.

And consider this: New research suggests it's not the type of macronutrient diet you follow (such as one emphasizing protein, carbohydrates or unsaturated fats) that makes a difference in reducing the risk of heart disease; rather, it's the healthy foods you eat.

An August 2019 study, published in the International Journal of Cardiology, involved 164 adults with high blood pressure or hypertension who were split into three groups that followed different diets. Each diet was rich in fruits and veggies, lean meats and fiber. Ultimately, all three diets reduced heart injury and inflammation in people with risk factors for heart disease. Emphasizing one macronutrient or another was less important than eating an overall healthy diet.

Additionally, forsaking an entire food group, like carbohydrates, can have repercussions. Your body uses carbs as fuel to keep it going. A low-carb diet decreases insulin levels, which forces your body to burn stored fat for energy (since you're not getting any energy from your food). That can cause weight loss, but it also causes fatigue, according to the Mayo Clinic.

Read more: Everything You Need to Know About Carbs and Why You Shouldn't Cut Them

The most effective diet for safe, maintainable weight loss as well as improved health is one that includes a wide variety of fruits and vegetables, whole grains and low-fat protein sources as well as consistent physical activity.

The real Mayo Clinic Diet is a lifestyle approach that gives you the resources to make these new healthy, sustainable habits. It's based on the Mayo Clinic Healthy Food Pyramid, which serves as a guide: Eat most of your food from the groups at the bottom of the pyramid and less from the top — and don't forget to exercise!

"We, at the Mayo Clinic, want people to eat a variety of foods in each food group in a way that fits their customary patterns and meets their nutritional needs — foods that they enjoy and foods that are nutritious," Zeratsky affirms.

Read more: How to Find the Best Weight-Loss Diet for You