What Is the Fast Metabolism Diet?

In This Article

The Fast Metabolism Diet aims to rev up your metabolism so that you can eat food—potentially lots of food—and still lose weight. The diet's inventor, nutritionist and wellness consultant Haylie Pomroy, claims you can eat three full meals a day plus two snacks, and lose up to 20 pounds in 28 days.

Your dietary goals are accomplished by rotating foods during the week. This, according to Pomroy, will speed your metabolism so that you burn more calories and lose weight.

The Fast Metabolism Diet does not require you to count fat or carbs, or to track your calories. It does, however, require you to stick with the allowed foods on the plan and to strictly avoid other foods. This part of the diet may pose a problem, since some of the foods that aren't allowed are incredibly common (wheat and dairy products among them).

The diet allows plenty of healthy fruits, vegetables, lean meats, and whole grains, which is a point in its favor. However, you're only allowed to eat certain things on certain days, which may be challenging for meal planning purposes. Its premise—that it's possible to make your body's metabolism run faster by eating only certain foods in a particular order—does not have any medical studies to back it up.

The diet also omits foods that nutrition experts agree are healthy for most people, including: whole wheat (high in fiber), milk products (a great calcium source), and egg yolks (in moderation, a great source of a wide variety of vitamins and micronutrients, ranging from vitamin D to selenium)

What Experts Say

"The Fast Metabolism diet focuses on eating fairly healthy foods and promotes exercise, but the structure and rules around the diet are regimented and are not based on science."

Kelly Plowe, MS, RD 

Background

Pomroy, a regular on NBC's Extra and Access Hollywood, has worked with celebrities ranging from Cher to Robert Downey Jr. on their weight loss and nutritional goals. She calls herself "the metabolism whisperer" for her focus on how the body burns calories and uses nutrients obtained through food.

The Fast Metabolism Diet, first published in 2013, has its roots in Pomroy's work in animal nutrition. In animal husbandry, it's possible to shape the type of meat produced by farm animals (fatty and marbled vs. lean) by manipulating the type of food the animals eat, which in turn would either rev up or turn down their metabolisms. Pomroy says she realized humans could achieve the same effect by eating different foods.

"Remember, your metabolism is your body's system for dealing with the energy you take in through food," Pomroy writes. "The metabolism shuttles that energy into different directions according to what you eat and what you do. The beauty of your metabolism is that it can be manipulated, because how you eat and move and live affects how much of your food is stored as fat, how much is used as energy, and how much is devoted to building the structure that is your body."

According to Pomroy, diets, low-nutrient foods, plus too much stress can slow down your metabolism, and weight gain is the result. The diet blueprint outlined in her book goes into detail on various hormonal effects of weight gain, plus the impact on your liver, your muscles, and your different types of fat.

The Fast Metabolism Diet has a devoted following, with many people stating that it helped them lose significant weight without going hungry. However, critics note that the weight loss that's possible on the diet seems to result from calorie restriction, not from the complicated schedule of different foods.

The diet might suit people who are seeking rapid weight loss but who are also willing to incorporate exercise into their routines, and who are willing to give up entire categories of foods to achieve their goals.

How It Works

The Fast Metabolism Diet has three phases, each of which has its own focus and distinct food lists. The phases rotate each week, and then repeat three times for four weeks in total:

  • Phase 1 (days one and two) is to "unwind stress and calm the adrenals."
  • Phase 2 (days three and four) is to "unlock stored fat and build muscle."
  • Phase 3 (days five, six, and seven) is to "unleash the burn," and focuses on your hormones, heart, and "heat."

The idea, Pomroy says, is to provide your body with the variety it needs in order to obtain all your necessary nutrients. "You need complex carbohydrates, natural sugars, protein, fat, and even salt to maintain normal body chemistry," she says, adding that you may need high levels of these elements, especially if you've been eating a poor diet for a long time. However, she says, you shouldn't include everything you need at once, which is the idea behind the different phases. Shifting between the phases allows the systems and organs targeted in each phase to rest and restore in turn, she says.

Phase 1: What to Eat

Phase 1 is the high-glycemic, moderate protein, low-fat phase. It includes carbohydrate-rich foods such as brown rice and quinoa, fruits that are high in natural sugars, and low-fat, moderate-protein foods.

What to Eat

  • Brown rice

  • Brown rice pasta

  • Quinoa

  • Oatmeal

  • Mangoes

  • Apples

  • Figs

  • Oranges

  • Lean beef

  • Turkey

  • Lentils

What Not to Eat

  • Foods with refined sugar

  • Wheat

  • Corn

  • Juice

  • Dried fruit

  • High-fat meats

  • Milk-based products, including cheese

Phase 1 includes breakfast, lunch, and dinner, plus fruit snacks. Breakfast consists of grain and a fruit, lunch includes a grain, a protein, a vegetable, and a fruit, and dinner features a grain, a vegetable, and a protein. This routine, according to Pomroy, teaches your body to use food as energy instead of storing it as fat.

Exercise in Phase 1 should include at least one day of vigorous cardio. Pomroy recommends running, working out on an elliptical trainer, or an upbeat aerobics class.

Phase 2: What to Eat

Phase 2 is the very high-protein, high-vegetable, low-carbohydrate, and low-fat phase of the Fast Metabolism Diet. It features high-nutrient cruciferous vegetables and lots of lean protein.

What to Eat

  • Leafy greens such as kale, collards, and mustard greens

  • Broccoli

  • Cabbage

  • Onions

  • Asparagus

  • Lean beef

  • White meat poultry

  • Buffalo/bison

  • Low-fat fish

  • Egg whites

What Not to Eat

  • Fruit or fruit juice

  • Grains (including corn and wheat)

  • Refined sugar

  • High-fat meat

  • Milk-based products, including cheese

Like Phase 1, Phase 2 includes breakfast, lunch, and dinner, plus two snacks. However, the emphasis is on foods that will build muscle, as opposed to relatively high-carb fruits and grains. Breakfast features lean protein and a vegetable, lunch is another protein and vegetable, and dinner is protein and more vegetables. Both snacks are lean protein, such as buffalo jerky or a few slices of deli chicken.

Exercise in Phase 2 should include at least one day of strength training, with a focus on lifting heavy weights with low reps.

Phase 3: What to Eat

Phase 3 is the high healthy-fat, moderate carbohydrate, moderate protein, low-glycemic fruit phase. It includes foods that are high in healthy fats, such as avocados and coconuts, lots of berries, some grains, and little meat.

What to Eat

  • Nuts, seeds, and nut butters

  • Avocados

  • Coconuts

  • Olives

  • Salmon

  • Berries

  • Asparagus

  • Beans

  • Cauliflower

  • Quinoa

  • Seaweed

  • Beef and chicken liver

What Not to Eat

  • Oranges

  • Peaches

  • Mangoes

  • Beef

  • Poultry

  • Corn and wheat

  • Refined sugar

  • Milk-based products, including cheese

Phase 3 includes breakfast with fruit, a fat/protein food, a grain, and a vegetable. Lunch features a fat/protein source, a vegetable, and a fruit, and dinner has a fat/protein source, a vegetable, and a grain/starch. Both snacks include a healthy fat plus a vegetable.

Exercise in Phase 3 should include at least one day of stress-reducing activity such as yoga or a massage.

Recommended Timing

It's important to the diet's success to follow the food and exercise timetable outlined in the three phases blueprint precisely, since, according to Pomroy, each phase helps your body recover from the last phase and prepare for the next phase.

Once you've gone through one week and all three phases, you can repeat the diet as many times as you wish until you obtain the results you want.

Resources and Tips

There are six rules that Pomroy says are critical to follow in order to see success with the Fast Metabolism Diet. They involve eliminating five foods that make up the bulk of many people's diets, plus one particularly common ingredient in popular beverages:

  1. wheat
  2. corn
  3. dairy
  4. soy
  5. refined sugar
  6. caffeine

To ease the pain of eliminating these dietary staples, especially caffeine, she recommends:

  • adding cinnamon to a morning smoothie
  • trying feverfew or gingko biloba, which may help with withdrawal headaches
  • patience

Still, some people may find that giving up their morning latte (neither the caffeine nor the milk is allowed as part of the Fast Metabolism Diet) is a bridge too far.

Pros and Cons

Pros

  • Diet contains lots of healthy fresh fruits, vegetables, lean meats, and whole grains

  • Exercise is strongly recommended

  • Different types of exercise are included

Cons

  • Diet is complicated to follow

  • Food choice is limited day-to-day

  • Program may be difficult to follow long-term

Pros

Healthy Foods

The foods included throughout the one-week span of this diet plan certainly are part of an overall healthy diet, which calls for lots of fruits and vegetables, lean protein sources, and whole grains. If you take the week as a whole, there's sufficient variety to keep you from getting bored, plus plenty of variation that should provide you with the vitamins, minerals, and micronutrients your body needs to function.

Exercise

The Fast Metabolism Diet recommends rotating between different forms of exercise: aerobic, strength training, and yoga. This is a recommendation that's well supported by research, since it keeps up your overall level of activity while allowing your specific muscle groups to recover on "off" days. Incorporating a high-intensity exercise such as running, weight-lifting, and flexibility training in the form of yoga will help you to get fit fast.

Cons

Complicated

Although Pomroy's book is filled with descriptions of how simple the Fast Metabolism Diet is to follow, it's actually pretty complicated. It would be easy to forget which foods you're supposed to eat (and avoid) on which days. Since the most effective weight loss program is one you'll actually follow, this one might not be ideal for some people. Pomroy does offer an app that helps in meal planning and in keeping the three phases straight day-to-day.

Limited Choices

While it's possible to limit your food options severely if you're only planning on doing it for a very limited time, you're likely to begin to chafe at the diet's limits if you stay on the program for very long. In addition, although the diet may help to introduce you to foods you don't normally eat, its regimentation probably won't help you to develop healthy eating habits long-term.

Although the Fast Metabolism Diet does include many healthy foods and a good, varied exercise plan, it's too complicated and too limiting to follow for very long.

How It Compares

Despite numerous positive reviews, there's no robust medical science behind the idea that the Fast Metabolism Diet actually will increase your metabolism. In addition, the day-to-day diet lacks balance and fails to meet the healthy diet recommendations outlined by the USDA.

However, there are research-supported ways to ramp up your metabolism without the need to restrict your food choices. If you learn how many calories you need per day (see the calorie calculator below), and then boost your physical activity level, it should boost your metabolism as well.

Similar Diets

Although there's plenty of information out there purporting to help you speed up your metabolism, Pomroy has turned the Fast Metabolism Diet into a franchise, with a companion cookbook and an app. Still, there are competing diets with more research behind them.

There's a bit of evidence that low-carb diets, such as the Atkins Diet and the South Beach Diet, may actually help to increase increase your metabolism. A study looking at weight maintenance following weight loss found that people following a low-carb diet burned more calories than people following a low-fat diet.

Now, this study isn't definitive, and it didn't even involve the diet phase of a weight-loss program, just the maintenance phase. But it indicates that you might have different choices in potentially metabolism-boosting diets. You also should note, though, that low-carb diets have nutritional issues of their own.

A Word from Verywell

Choosing a weight loss program can be confusing. It's easy to buy into the hype surrounding popular diets, especially if the diet in question is presented with celebrity backing plis hundreds of glowing reviews.

The Fast Metabolism Diet might help you to lose weight—lots of people report that it works, at least in the short term. But long-term, it won't help you to develop the healthy eating habits that will sustain your weight loss beyond that initial effort. To accomplish that goal, you'd be better off trying Weight Watchers or the Mayo Clinic Diet, both of which address short-term weight loss and long-term maintenance, plus healthy eating.

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