What Is the M-Plan Diet?

If you like mushrooms and are looking to lose weight, you may be wondering if the M-Plan diet is right for you. Followers of the M-Plan, also known as the mushroom diet, replace one meal each day with a mushroom-based meal for 14 days. Reports indicate that celebrities like Katy Perry and Kelly Osbourne have had success on the M-Plan diet.

Proponents of the M-Plan claim the diet can reduce fat in the thighs, hips, and waist—without losing bust size in women. However, it is not possible to spot-reduce fat in some areas of the body and not others. The M-Plan is simply a fad diet that is not backed by any scientific evidence to support its weight-loss claims.

While individualized meal plans that are developed by registered dietitians are the most likely to be healthy, effective, and sustainable, the origin of the M-Plan is unknown. There is no website or company that takes credit for the eating plan. Much like the 3-Day Military Diet, the M-Plan diet seems to be an internet phenomenon more than a legitimate weight loss program.

What Can You Eat?

In addition to two regular meals a day, this two-week diet calls for one meal consisting of cooked mushrooms. Any variety of mushrooms is permitted.

What You Need to Know

The mushroom diet is functionally a meal substitution diet where one meal a day is replaced by mushrooms. Advocates of the M-plan suggest roasting, steaming, or sauteeing the mushrooms using as little fat as possible.

Most grocery stores carry common varieties like white mushrooms (also called Agaricus mushrooms), button mushrooms, and meaty-tasting portabella mushrooms. But the M-Plan also allows more exotic types of mushrooms, like chanterelle, shiitake, or cremini. For the rest of the meals on the M-Plan, you are instructed to consume your usual diet.

Pros and Cons

While the mushroom diet seems like an easy, quick way to lose weight, the eating plan has its drawbacks.

Pros

Simple

With just one rule—replace one meal a day with cooked mushrooms—the mushroom diet is easy to understand and follow. The diet doesn't require counting calories or carbs or even keep an eye on portion control or other foods, though this approach does not encourage long-term healthy habits.

Filling and Nutritious

Mushrooms themselves can be a nutritious addition to any eating plan and can be a complement to eating plans geared toward weight loss as a healthy, low-calorie substitute for higher-calorie foods. Nutritional expert Heidi Diller, RD explains why replacing aspects of a higher-calorie meal with healthy options like mushrooms can make sense:

“Mushrooms are loaded with vitamins and minerals [copper, vitamin B3, vitamin B5, potassium, phosphorus, and iron] and have very few calories, so they make the perfect diet food," she says. "In fact, using mushrooms as a meat substitute is a perfect way to lower the calories of any meal. Plus, mushrooms have proven to be just as satiating as meat.”

Cons

Spot Reduction Is Impossible

“The promise that mushrooms are magical in some sense and can whisk away fat from hips and thighs and not the breast area is nonsense," Diller says. Just as spot reduction through exercise is a myth, the same goes for diet. No individual food or diet can target fat burn in certain areas of the body. That's just not how weight loss works.

Doesn't Consider Overall Nutrition

Adding mushrooms to an entree or making them the star of a meal can be a smart way to reduce calories for weight loss. But if you pile on the calories for all your other meals and snacks, the mushroom diet won't work for you. You still need a calorie deficit to lose weight.

Doesn't Encourage Healthy Habits

With the sole focus on meal substitution rather than a balanced diet, the M-Plan doesn't encourage the adoption of healthy long-term eating habits. The diet provides no guidance for other meals and snacks, and in claiming followers can eat "normally" for two of their three meals a day and still lose weight, may actually encourage less nutritious meals.

Is the M-Plan a Healthy Choice for You?

The M-Plan diet's flexibility makes it similar to some other substitution-based eating plans and generally offers an improvement on other mono diets (plans that focus on a single food) as it allows for other foods throughout the day. Provided that the non-mushroom meals are nutritionally balanced (which could be a big "if"), this diet should provide all the necessary nutrients.

And because the mushroom diet doesn't specifically exclude other food groups, it can be aligned with some of the basic advice for healthy eating suggested by the U.S. Department of Agriculture (USDA). But since the diet plan doesn't provide any guidance for meals, followers would have to make an effort to otherwise follow recommendations for a healthy, balanced diet.

The USDA's dietary guidelines suggest eating a balanced mix of protein, grains, fruits, vegetables, dairy products, and healthy fats each day, from a variety of sources. This approach will help you get all the nutrients you need. While mushrooms are technically fungi, they're classified with vegetables. Eating more of them will help you get your recommended daily servings of veggies.

The M-Plan is naturally lower in calories since a serving of mushrooms contains fewer calories than a serving of other proteins such as red meat or poultry. For weight loss, the USDA recommends a reduction of about 500 calories per day. On a 2,000 calorie diet, that's a goal of roughly 1,500 calories per day. However, this number can vary a lot based on age, sex, weight, and level of physical activity. If you're interested in determining your own calorie guidelines, you can use this calculator.

Health Benefits

Of course, mushrooms are packed with nutrients and make a healthy addition to any balanced diet. They are low-calorie and low-carb, and they're a good source of fiber, potassium, B vitamins, vitamin D, iron, and even a little protein. Mushroom-based meals can also be filling, which promotes satiety and satisfaction to leave you feeling fuller longer.

However, it is not possible to spot-reduce fat by replacing one meal a day with mushrooms for two weeks. Nor is this simple substitution a recipe for long-term health and weight loss.

Health Risks

Though there are no known risks of replacing one meal a day with mushrooms, this unusual regimen could lead to unhealthy eating habits and disordered eating. Additionally, the fact that the M-Plan targets women seeking to lose fat from their "problem areas" promotes negative body image and could lead to self-esteem issues.

It's also important to note that some wild mushrooms are poisonous, so no matter your diet plan, it's important to stick with supermarket varieties unless you are an expert forager.

The only way to lose weight is to burn more calories than are being consumed. Weight loss simply cannot be targeted to specific parts of the body.

A Word From Verywell

If you're looking for a simple way to lose a few pounds, the mushroom diet might work. There’s nothing wrong with replacing one meal each day with a healthy, veggie-based dish. That can be a great way to improve your nutrient intake and reduce your daily calories. But mushrooms have no magical power to preserve the bust while also reducing the waist. To lose weight, reduce calories in a way that works for you, and be sure to get enough sleep and exercise, too.

Remember, following a long-term or short-term diet may not be necessary for you and many diets out there simply don’t work, especially long-term. While we do not endorse fad diet trends or unsustainable weight loss methods, we present the facts so you can make an informed decision that works best for your nutritional needs, genetic blueprint, budget, and goals.

If your goal is weight loss, remember that losing weight isn’t necessarily the same as being your healthiest self, and there are many other ways to pursue health. Exercise, sleep, and other lifestyle factors also play a major role in your overall health. The best diet is always the one that is balanced and fits your lifestyle.