What Is the Mushroom Diet?

If you like mushrooms, then this is the diet for you. Followers of the M-Plan (reportedly including celebrities Katy Perry and Kelly Osbourne) replace one meal each day with a mushroom-based meal. After 14 days, they claim to have slimmer thighs and tinier waistlines, but maintain their cleavage.

Often, weight loss programs that are developed by registered dietitians or credentialed diet professionals with a strong nutritional background are most likely to work. But no one knows who came up with the mushroom diet.

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.

You can eat any variety of mushrooms on the diet. They are low-calorie and low-carb, and they offer lots of fiber, potassium, B vitamins, iron, and even a little protein. Use them to replace the starch or meat in an entree, and you'll lower its calorie count significantly.

Most grocery stores carry common varieties like white mushrooms (also called Agaricus mushrooms), button mushrooms, and meaty portabella mushrooms. But you can also use more exotic types of mushrooms, like chanterelle, shiitake, or crimini. You can also blend the different varieties together. For the rest of the meals on your 14-day M-Plan, consume your usual diet.

To be successful on the plan, you should roast, steam, or saute the mushrooms using as little fat as possible. If you load the mushrooms up with heavy sauces or spreads, then you're not likely to lose weight. To keep the calorie count low, you could eat the mushrooms raw. Or to get more nutrients, drizzle them with a teaspoon of olive oil, sprinkle with salt and pepper, and cook in a 400-degree oven for about 15 minutes.

Some wild mushrooms are poisonous, so stick with supermarket varieties unless you are an expert forager. Although it is rare, some people are allergic to mushrooms or have a reaction to mushrooms if they are allergic to mold. And some people are susceptible to uncomfortable side effects if they consume mushrooms with alcoholic beverages.

Simple and Practical

With just one rule, it's easy to understand and follow this diet. There's no need to count calories or carbs or even keep an eye on portion control.

Filling and Nutritious

Nutritional expert Heidi Diller, RD, explains why replacing a higher-calorie meal with lower-calorie 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. In fact, using mushrooms as a meat substitute is a perfect way to lower the calories of any meal at only 44 calories per cup. Plus, mushrooms have proven to be just as satiating as meat.”

Incorporating more mushrooms into your diet could be an effective weight-loss strategy. But remember that not all of the mushroom diet's claims are legit.

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," says Diller. 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.

All Calories Count

Adding mushrooms to an entree, or making them the star of one meal a day, is a smart way to cut calories. 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.

The M-Plan diet's flexibility and focus on healthy ingredients makes it similar to some other healthful eating plans (and an improvement on other mono diets, or plans that focus on a single food). It's also aligned with the advice for healthy eating suggested by the USDA.

The USDA's MyPlate guidelines suggest eating a balanced mix of protein, grains, fruits, vegetables, and dairy products each day, from a variety of sources. This 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 daily servings of veggies.

If you like the idea of the M-Plan but aren't a fan of mushrooms, one of these other eating plans might work for you instead. But avoid stricter mono diets, in which one food is eaten almost exclusively.

Mushroom Diet

• General nutrition: Provided that the non-mushroom meals are nutritionally balanced (which could be a big "if"), this diet should provide all the necessary nutrients.
• Practicality: Mushrooms are easy to shop for and cook, and there is no calorie or carb counting. So it should be pretty simple to follow this diet.
• Effectiveness: This eating plan could be effective for weight loss, depending on the overall diet. However, it can't promise to keep weight on in certain areas of the body while keeping it off in others.
• Sustainability: This diet is only meant to last 14 days, but given the flexibility and variety of foods it allows, it could be used for longer than that.

Mono Diet

• General nutrition: On a mono, or monotrophic, diet, followers choose just one food and eat it exclusively for a short time (usually a week or two). This is an extreme version of the mushroom diet, and it's not a healthy option.
• Practicality: In some ways, this is a very easy diet to follow. You do not have to think about calories, carbs, or meal planning at all. But of course, eating only one food day in and day out is not actually practical at all, as your body and brain crave variety.
• Effectiveness: Like the mushroom diet, the mono diet works through calorie reduction. So it probably will lead to weight loss for most people.
• Sustainability: Unlike the more flexible and reasonable mushroom diet, the monotrophic diet is not a sustainable way to eat, even for a short time.

80/20 Diet

• General nutrition: On an 80/20 diet, followers eat a "clean" (whole-food, lower in calories, carbs, and fat) diet about 80 percent of the time. During the remaining 20 percent, they allow indulgences such as sugar and alcoholic beverages. Nutritionists say this a healthy, balanced approach.
• Practicality: Once you have a good handle on what an 80-percent day or meal looks like, this diet is simple to follow, much like the M-Plan. There is no need to count calories or carbs and the focus is on healthy ingredients.
• Effectiveness: Depending on your starting point, this diet could help promote weight loss in the same way the mushroom diet does. But for some people, calorie counting may be required, or a different breakdown of clean foods vs. indulgences (say, 90/10 instead of 80/20).
• Sustainability: Because indulgences are allowed, followers don't feel deprived; and because the plan is simple and safe (like the M-Plan), this diet is a suitable long-term option.

Flexitarian Diet

• General nutrition: A flexitarian diet is also called a semi-vegetarian diet. It means consuming a mostly vegetarian diet but eating meat occasionally. It provides a healthy balance of nutrients.
• Practicality: Just like the mushroom diet, this diet offers a wide range of food options, and has few rules or requirements. There's no calorie counting, eliminating food groups, or buying special supplements or ingredients.
• Effectiveness: While the mushroom diet is touted for weight loss, the flexitarian diet is not. But since it emphasizes whole foods, mostly plant-based, it can promote weight loss for some followers.
• Sustainability: It's healthy, safe, and practical to follow this diet for life.

If you're looking for a simple way to shed 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 whittling the waist. To lose weight, cut calories in a way that works for you, and be sure to get enough sleep and exercise, too.