Fast Metabolism Diet is based on the diet book by nutritionist and wellness consultant Haylie Pomroy. Published in 2013, the book put forward some drastic deviations from conventional weight loss regimen. The 28-day diet plan promises to increase your metabolism and put it into fat-burning mode. It is all about eating well and helping the body burn more fat for energy, rather than starving to lose weight. The diet is presented in a very structured way with separate meal plans prescribed for the different phases involved. There is no severe calorie restriction in any of the phases, but there are several food restrictions, including cutting out wheat and dairy completely.

How the Fast Metabolism Diet Works

Fat Metabolism Diet is a 3-phase diet plan like several other weight loss diets out there. But one major difference is that the phases are not linear, with one following the other, as you generally find in other diet plans. They are cyclical, each of the 3 phases being 2-3 days long and repeating every week. The meal plans for these phases vary as follows:

Phase 1: (Day 1 and Day 2) – High in carbohydrates with moderate amount of protein and low fat.

Called ‘Unwind,’ this phase is meant to put our body at ease, since carbohydrates are easy to digest and are the body’s energy source of choice.

Phase 2: (Day 3 and Day 4) – high in protein and vegetables, but low in both carbohydrates and fat.

This phase is called ‘Unlock’ and is projected as promoting the utilization of stored fat because intake of dietary fats and carbohydrates is severely limited.

Phase 3: (Days 5-7) – High in healthy fats with moderate amounts of carbohydrates and protein. It includes some fruit too. This phase is known as ‘Unleash’ and you are expected to continue fat burning at full swing, both the stored fat and the good fats you are taking.

This phase should ideally coincide with weekends because it allows larger variety and liberal portions of all food groups as compared to the other two phases. Well, that makes Monday the best day to start the Phase1.

Many weight loss diets advocate calorie confusion to keep the body from adapting to calorie restriction. But, as you can see, Fast Metabolism Diet is based on nutrient confusion, and prescribes varying amounts of protein, fat, and carbohydrates on different days.

During each phase, the portion sizes depend on how many pounds you want to lose. Contrary to expectation, larger portion sizes are recommended if one has more pounds to lose, and the portion sizes reduce as you progress in your weight loss journey. For example, the basic portion sizes are meant for people who have 20 pounds or less to lose, but if you need to lose more than 20 pounds, you should take basic portion size X 1½. Those who have over 40 pounds to lose should double their intake of vegetables along with 1½ times the basic portion of other foods at every meal.

The basic plan consists of 4 weeks of cycling through the 3 phases, but if you still have extra weight after this period, the program can be repeated until you reach the target weight. You are expected to weigh yourself at the end of each 4-week set and regulate your food intake according to the number of pounds you still need to lose.

Is Exercise Involved?

Every phase of the Fast Metabolism diet has a prescribed exercise program that corresponds to the eating plan of that phase. For example, in Phase 1 that is usually on Mondays and Tuesdays, cardiovascular exercises are recommended, but not on both days. One of these two days should be set aside for an intense workout, but the other day you should take it easy to allow the body to recover.

In Phase 2, the protein-rich meals should be accompanied by muscle-building exercises such as strength training with weightlifting. Contrary to what one would expect, Phase 3, with its calorie-rich meal plans high in fat and moderate amounts of the other two macronutrients, does not contain any heavy or vigorous activities. Gentle exercises like yoga or a session of body massage are prescribed for these days.

Nutritional Profile

The nutritional profile of the diet is a healthy mix of all macronutrients, so it is unlikely that dieters would have any nutritional deficiencies while they’re on this diet. You get sufficient amounts of protein, carbohydrates and fats on a weekly basis even though daily intake may vary. Although fruit juices and dried fruit are excluded, one may get sufficient supply of vitamins, minerals, and fiber from vegetables and the fresh fruits allowed in each phase.

The Cost Factor

The Fast Metabolism Diet may appear to be quite cheap since the main expense involved is buying the diet book, which is available for as little as $5 for the kindle version. Even if you want the additional support offered by the cook book by the same author, it doesn’t cost a lot. But the actual cost of the diet is hidden; it is in getting all the meals according to the diet guidelines, while avoiding a host of common food ingredients like wheat, corn and soy products, sugar as well as all sweeteners, fruit juices, coffee, alcohol etc.

Do Dieters Lose Weight on the Fast Metabolism Diet?

Those who follow the Fast Metabolism Diet in letter and spirit obviously shed some pounds, but most of it can be attributed to cutting out sugar, processed foods, dairy and grains such as corn and wheat. It is not clear whether the nutrient confusion employed to manipulate metabolism has any great role in effecting weight loss. It is easy to see that the focus is on protein intake, which is generally accepted as helping weight loss by building muscle and increasing metabolic rate even at rest. So the diet may work as well as the many high-protein diets out there, if not better.

Level of Effort

The meal plans look rather liberal at first glance, but the food restrictions take quite a bit of effort to adhere to. The list is long, and you may find it quite impossible to follow it strictly, unless you cook every meal from fresh, basic ingredients. For instance, the basic Phase 2 menu includes 4oz meat or 6oz fish or ½ cup of cooked beans per meal along with unlimited vegetables and a slice of fruit per meal, which sounds like a good deal. But, you have to prepare these items without the use of any oil or fats and the vegetables and fruit have to be phase appropriate. And the only phase-appropriate fruit in this phase is lime and lemon.


Fast Metabolism Diet has several sensible guidelines for healthy eating and optimum nutrition, and it may be worth buying the diet book as well as the cookbook. However, it may not produce the quick weight loss results that one would expect from this extremely detail-oriented diet. Although the diet claims to be adaptable to vegetarian and vegan preferences, very few food choices are actually available, even with the concessions on dairy consumption.  The diet may be healthy, but not very practical for busy people. One may have to cook in large amounts to have all the meals ready throughout the week. People with lots of time and a whole lot of patience to cook the meals according to the menu can give it a try.
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Written by Kylie Daniels

My name is Kylie Daniels and I have a strong passion for health and nutrition. I was raised in Southern California, and am now attending Boise State University in Idaho to complete my B.B.A. degree in General Business and Marketing. My interest began a few years back when I was a part of the opening of a brand new juice bar. Here I learned the importance of eating healthy, balanced exercise, and the power of a nutritional lifestyle. This education has inspired me to research the latest diets, cleanses, and products to help guide you to be your best self!

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