Does The Fast Metabolism Diet Really Work as Promised?

fast metabolism diet bookThe front cover of the Fast Metabolism Diet book claims you can eat more and lose up to 20 pounds in 28 days. But does it really work the way it’s advertised?

The answer is yes and no. There are a lot of misconceptions about this plan you need to know of before you try it and that’s exactly what you’ll find here.


The Fast Metabolism Diet explained:

There are 3 phases to this diet which you go through every single week, for 4 weeks straight. Each phase involves eating in a different way which is meant to trick your metabolism into rising. This is known as interval eating to some, cyclical eating to other. You get to eat 5 meals a day: Breakfast, snack, lunch, snack & supper. 

How much can you actually eat on this plan?

Picking apart hype from truth: However, even though the author of this book, Haylie Pomroy claims you can eat more and lose weight through her plan, in reality this diet may be very restrictive on how many calories you can consume everyday, something that everyone considering trying this diet should be aware of.

Even though you can lose weight with this diet, it’s got nothing to do with what’s written on the front cover. 

Breaking it down: How it REALLY works:

The diet lasts for 4 weeks (28 days).

Each day that you are on this diet, you will be allowed to eat 5 times.

Each week, you go through 3 eating phases. Each phase allows for a limited amount of calories to be eaten. Here’s how each phase looks broken down: 

Phase 1:

This lasts for the first 2 days of the week. Within this phase, you are only allowed to eat 800 calories a day. Here is a sample list of foods you’re allowed to eat during phase 1:

Protein: Lean meat, chicken, beef, buffalo meat, turkey, foul, sausages, turkey bacon, eggs.

Fruits: Apples, guava, mulberries, oranges, peaches, pears, kiwis, watermelon, limes, lemons, figs. 

Vegetables: Beans, broccoli, spinach, peppers, peas, sweet potatoes, turnips, pumpkin, celery, carrots.

Drinks: Only water. It is recommended to only drink half your body weight (in ounces) a day.

Phase 1 sample menu plan (for 1 day):

Breakfast: Eggs sunny side up and turkey bacon.

Snack: 1 apple.

Lunch: Chicken breast, sweet potatoes and beans.

Snack: A bag of baby carrots.

Supper: Sausage with eggs, peppers and broccoli. 

You can repeat a similar meal plan for day 2. Remember to keep the total calories under 800 during phase 1.

Phase 2:

This phase lasts for the next 2 days. The food list here is the same as for phase 1, but the focus during phase 2 is more high protein, low carb foods. The rule for this phase is that your total daily calorie intake can’t go over 700 calories.

Phase 3: 

The last phase will go on for 3 days. Here things are a bit more flexible and you can eat in anyway you want from the food list above. The total caloric consumption can’t go over 1,200 each day.

Putting it together:

  • Phase 1: Lasts 2 days, eat 5 meals a day, low carb foods, no more than 800 calories total. 
  • Phase 2: Lasts 2 days, eat 5 meals a day, low carb, high protein foods, no more than 700 calories total.
  • Phase 3: Lasts for 3 days, eat 5 meals, mix up meals anyway you want, no more than 1,200 calories total.
  • Repeat Phases 1-3 for another 3 weeks.
  • Total length of diet: 4 weeks.


Can you really lose 20 pounds in 28 days with this plan?

Yes it’s possible. But it’s for 2 main reasons:

1. Low calorie intake each day. Again this isn’t written on the cover, but there is nothing in this diet that will let you eat more. It’s a very low calorie diet as you saw above. This will help with the initial weight loss.

2. Changing your eating routines every few days. This is basically a form of interval eating, a method of eating where by mixing up your eating routines every few days, you can trick your metabolism into increasing, losing more weight and never hitting a plateau.

The good news is that in the Fast Metabolism Diet, calorie shifting is used and does work.

The bad news is that not only is interval eating not utilized to it’s full potential, but it’s also inhibited due to the restrictive eating regimes. In interval eating, you should be allowed to eat more and there shouldn’t be that many food restrictions. This makes it work and if done correctly, it can help you lose even more weight than with the Fast Metabolism Diet.


  • You can lose 20 pounds in 28 days with this diet.
  • Utilizes calorie shifting, a great way to lose weight without hitting a plateau, but not to it’s full potential.


  • VERY restrictive diet. 800, 700, 1,200 calories a day may be difficult for most to handle.
  • Not sustainable. It’s very difficult to stay on this diet after you finish it, thus results are likely to come back.
  • Disingenuous. Says you can eat more and lose weight, but doesn’t do it in the book.

Fast Metabolism Diet Score:

2 stars

2 stars out of 5. Good weight loss results, but pretty restrictive and doesn’t in my opinion do exactly what it says on the cover.

fast metabolism diet score

Should you try this diet?

The cons out weight the pros in my opinion. It does work and you can lose weight, but the work it takes to get there is just not worth it, not to mention the maintenance needed after you finish it a lot of people may find issues with. 

The only good thing about this diet is that it somewhat utilizes calorie shifting, an uncommon yet VERY powerful method of weight loss. Unfortunately the Fast Metabolism Diet does NOT utilize calorie shifting to it’s full potential.

In calorie shifting like it was mentioned before, you aren’t as restricted. There’s short/long term results and you can still lose more weight under real calorie shifting than under the Fast Metabolism’s version of it. If you are looking to get faster weight loss results with much less restrictions, try this free eBook on getting rid of fat fast which does exactly that:


In truth, the Fast Metabolism diet comes close to finding that ideal solution to fast weight loss, but it still inhibits itself by sticking to the traditional, low calorie, low-carb approach to dieting which is why it got 2 stars. 

I personally feel any diet based on deprivation is just not a smart way to lose weight, but that’s my personal opinion. If you agree/disagree, I’d like to hear what you have to say.

23 thoughts on “Does The Fast Metabolism Diet Really Work as Promised?”

  1. Yesterday I completed day 28. I have followed the diet religiously, no cheating whatsoever. I have increased my exercise and added light resistance training. Today I have lost 6 pounds and no one has noticed including the husband. Of course, I am extremely disappointed. I don’t know whether to drink a bottle of wine today or start the diet again! However, on the flip side, some how I have lost inches. It cannot be muscle as I have not done enough to build it. So advice is welcome. Join me for a bottle of wine or push me into another 28 days of deprivation in the hopes that my metabolism will kick into high gear?

  2. Haylie is against calorie counting. She says you can eat as many veggies (not all veggies are allowed) as you want in any of the phases, even between meals, so the calorie count certainly does not have a MAX.

    I am disappointed in this review. This diet is expensive (compared to what I spent before), and it is very strict and requires a lot of discipline as the allowed foods are limited (no nitrites, no sugars, nothing artificial, no dairy, no corn, and so on). Not everyone loses a lot of weight on it, but there is a scientific reason for that as well. The book really does explain it quit in detail. I don’t mean to offend you, but I don’t think you read the whole thing in its entirety.

    • Right but most of the foods you get to eat are low in calories so even when eaten in endless amounts, you still don’t consume that many calories.

      • Your phase 1 sample is not accurate. Phase 2 is carb -based with steel cut oats, tortillas, quinoa, rice, etc, which does not appear in your post. It is well over 800 calories and calorie counts are not mentioned anywhere in FMD.

    • Syl, you are sooo right! I agree with every single word! I’ve done FMD 2 years ago and lost 20 pounds in 2 rounds of 28 days. I never needed to count calories, never. I ate veggies (the allowed ones) until being satisfied. And never gained those pounds again. FMD really Works. It changes your metabolism for good. Regards from Flavia, Rio de Janeiro -Brasil

  3. I’m not sure where you are coming up with calorie counts- as it doesn’t mention counting calories in any section of the FMD book. It also states that you can eat as many vegatables as you want- unlimited. So this review really is not accurate in any sense as it is not “Calorie Restrictive”.

  4. I have hypothyroidism and I really hoped this diet would jumpstart my metabolism. Unfortunately, after the first week weight loss 5 lbs., I couldn’t lose any more for 2 weeks. I also got extremely tired and constipated, and got headaches on phase 1. I discovered that the cruciferous vegetables I was eating in abundance (and raw) seemed to be slowing down my metabolism rather than speeding it up. I also felt quite sick eating so much meat. The benefits of eating whole grains and no sugar/simple carbs was a good lifestyle change however–and good for my thyroid. The bottom line for me is that this diet was problematic for my thyroid and left me more tired and sluggish than ever. I am going into the 4th week and modifying the eating plan to support my thyroid functioning better and I hope it works.

    • Yeah this diet is not suitable for this condition Lara. You should treat the thyroid problem first before attacking the weight issue. You should try the supplement called SeaVegg (it’s great for this problem!).

  5. I am on this diet now and an not following the portion sizes, just eating the foods on the list when I am hungry. I didn’t follow rules about eating upon rising, excercised but not in the order/timing suggested. No calorie counting! I don’t think I even stuck to the snack vs. meal or how many times a day to eat. It works for me that way and I am down 8+ pounds in 2 1/2 weeks. Eating healthy feels better. There is a community on Facebook to join/share tips if you are seriously sticking to the plan that has been helpful. Paleo and the Raw food diet are also healthy and probably many others as well. My thoughts – just pick the one that you can stick to – and cut out processed foods! In the past I’ve also used Glucomannan (spell), a fiber supplement so try that if you are feeling hungry a lot, you can get it online many places.

  6. This is an awful diet! It should be called the starvation diet. I added up calorie intakes for the first 3 days. I followed her rules and recipes. I did eat an extra snack because I was so hungry. Day 1 1,078 calories, day 2 1,100 calories, day 3,680 calories! I gave up on night 3 and had something to eat with some fat in it.

    • Yeah this is just another starvation diet. Try to find your BMR and eat based on what it is or you can do the 3 week diet which is more flexible than this one Rachel.

    • You are supposed to eat until you are not hungry on her diet. You are supposed to snack even if you do not feel hungry. You are supposed to not let yourself stay hungry. Did you even read the whole diet plan?

      • I’ve been doing this diet for 4 days and I gotta say this is entirely untrue. I’ve been so full all day every day on this diet, even in phase 2 which people have said is supposed to be the hardest. I haven’t checked my weight loss yet (waiting till the whole week is over to see how it went), but making the change to eating whole foods and lots of veggies has had me feeling fantastic. IMO this is far from a “starvation” diet. This is the way human beings were meant to eat.

  7. I’m not sure where your calorie amounts are coming from , but according to the food sources and quantities allowed, my count is 1422 for Phase 1, 793 Phase 2 and 1441 in Phase 3.

    Just 2 cups of cooked brown rice ( required in Phase 1) comes in at 432 calories
    Add 4 pears or apples and there’s another 400 calories.

  8. Hi Haylie!! I see you are calling yourself Edie now and responding to those who criticize your b.s. I suggest everyone try the South Beach diet, which you obviously emulated but did your own spin. Those of you who don’t believe me, try both and you will see which one truly works. Of course you will lose weight if you only eat 800 calories a day. Anyone who tries this joke diet will absolutely end up starving. Wow this diet is a joke.

    • Lots of diets are based on styles of each other but I agree, there isn’t a big difference between the Fast Metabolism Diet and other low calorie ones. I didn’t know about that name change though.

  9. Of course, every one has to choose the weight-loss regimen that they feel works for them. For me, the Fast Metabolism Diet (FMD) has been an amazing and great experience. The FMD is NOT a diet based on calorie- or carbohydrate-counting. It is a diet based on (1) repairing our beleaguered metabolisms, and then (2) learning how to eat in a healthy way.

    I’ve lost 11 pounds on the FMD In a little over a month. I’ve never eaten so much in my life, and have never had so much success with a diet. The FMD is “restrictive” in that we are asked to give up caffeine, corn, wheat, and sugar. I can honestly say, coffee fiend though I was, that after the first week I have not missed my morning 4 cups of coffee. Nor have I missed the sugar, wheat, or corn, given the success I’ve had with the regimen.

    Most of all, I’m thrilled that I can use the tools I’ve learned from the FMD about how to eat well and in a healthy way to maintain my weight loss.

    • Well I agree with Edie. I was shocked to read here 800 calories per day.
      I stayed within the parameters except for one cup of black coffee per day, which I will not give up.
      I lost 11 pounds and ate great. I will say I do not enjoy phase 2. I’m not a big meat eater and I like my sprouted bread for breakfast. So phase 2 is like turkey salad turkey salad, blah blah. But phase 3 is so worth the wait!


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