How The 3 Week Diet Will Make You Lose 23 Pounds of Fat in 21 Days.

By | November 23, 2014


Website URL:
Ease of Use: Very easy-moderate
Guarantee: 60 days.
Cost: $47.
Average Weight Loss: 15-23 pounds in 21 days.
Overall Effectiveness: 4 out of 5 stars (Excellent).

A perfect diet does not exist, but the 3 week diet comes very close to it, not because of how much serious weight you can lose, but because it has a very manageable and flexible plan after you do the diet that can make sure you never have to diet again and anyone can follow it and it’s yo-yo proof.

The 3 weeks on this diet can help you literally lose 23 pounds of fat. The diet itself is not very easy at first, but it’s MUCH easier than most of the others out there and it’s short and works across the board.

The claims of the 3 Week Diet that are actually true:

The actual weight loss promise: 23 pounds in 21 days. Is it true? Yes it is. 

Very little exercise needed. Somewhat true. 20-30 minutes about 3 times a week or everyday if you can do it.

You can lose in 3 weeks what people lose in 3-4 months. True. A majority of the diet focuses on releasing and getting rid of fat storage in the body which will contribute to most of the weight loss results.

You can eat anything you want, anytime you want. After the diet is done, yes, but as long as you follow a specific rule regarding BMR which will be explained.

You’ll actually eat fat to lose weight. This is also true. One of the parts of the diet is based on that and it makes the diet more interesting to do.

Some of the claims are quite out there, I’ll admit, but I just finished reading the entire booklet on this diet plan, written by Brian Flatt who is a personal trainer and there is solid evidence and proof to back up the strategy and power of this diet. 

How the 3 week diet works (Brian’s genius plan):

There are 4 phases to this plan, all of which span for a total of 21 days. The way this diet works is that it combines a number of dieting methods into one powerful plan. The truth is that it’s optional to go for all 4 phases, but for the best results, it is recommended to follow it all the way through until the end of phase 4. 

The main idea behind this diet that all that weight (the 23 pounds in 21 days) come from burning up fat where the bulk of weight issues (and health issues) come from. This diet aims to get rid of that through each phase as well as an exercise plan.


Brian makes a few things very clear early on:

1. If you eat less calories than your BMR, you will lose weight consistently, regardless if you follow the diet or not. So even if you stumble somewhere, stick to eating less per day than your BMR and you’ll lose weight gradually as it will help fat get rid of fat storage’s in your body. BMR calculators can be found online (they’re free). 

The only problem with following this is that results will be pretty slow, but steady. Brian cites that we need to burn more than 3,000 calories to get rid of a pound of fat so even if we eat under our BMR but even a few 100 calories, it’s still going to take weeks-months to burn off substantial weight and if you’re 10, 20 or more pounds overweight, it will be even longer than that.

If you want much faster results however, this is where the 3 week diet will come into play. It aims to get rid of any and all fat deposits in your body through it’s approach and the rest is going to be all about eating under your BMR.

2. This diet is meant for very fast results. In addition to eating less than your BMR, the other phases aim to put results into overdrive. Brian understands people want very fast results so he’s taken the best of several diets proven to work, put them together for a much more powerful effect. Alone the diets work to a point, but together, there’s a much bigger result.

3. Brian explains that the body can either be in a state of being fed or fasting. Fed means you supply it with food so it will burn the calories from that and fast means it will have to burn fat from within your body when there’s not much food or sources of carbs to burn. This will cause weight loss. One of the goals of this diet is to help the body feel it’s in a fasting state.

This doesn’t mean you’ll be starving yourself. It means you’ll be eating foods that the body will burn easily, but because there will be less carbs involved, it will use energy from your fat deposits and burn that, leading to weight loss.

Get started with the 3 week diet.

If there were a few diet styles I could explain that make up the 3 week diet, it would be:

  • Intermittent fasting.
  • High fat/low carb diet.
  • General low carb diet and a lot of protein.
  • Interval training (exercise).

Why you will lose so much weight: The 4 powerful phases of the diet :

Phase 1: Lasts for 7 days.

This part of the plan is meant to detoxify the body and help you lose weight like it’s needed “yesterday” as Brian says. 5-10 pounds is what the expectation is here. 

The first day you’ll be eating 4 meals, 3-4 hours apart and they are only going to be vegetables. It’s tough, but it’s only going to be for one day. 

The next 3 days you’ll add protein foods into the diet and alternate them, eating 2 meals out of the 4 with protein and the other 2 will be just vegetable. 

The last 3 days of the diet will involve adding proteins to all 4 meals which means no more alternating. Every meal you eat will be mixed.

Sample foods:

Vegetables: Beets, carrots, broccoli, tomato, spinach, onions, peppers, mushrooms, kale, cabbage, aritchoke and more.

These vegetables can be steamed, broiled or microwaved. 

Proteins: Chicken, beef, eggs, fish and other related foods which have protein (list is provided inside diet plan)

You can ONLY drink water during these 7 days.

Phase 2: Lasts only 1 day

You’re going to be fasting on day 8. To make this easier to deal with, Brian recommends having your last meal at night, so you can sleep through a large portion of the fast and eat the next night. 

Phase 3: Lasts 3 days

This phase is the one which interested me most. You’re going to be eating a high fat/low calorie/low carb diet and ironically with what Brian explains and the studies he cites, you are actually going to lose a lot of weight. 

You are told to eat anywhere from 1,200 calories (women) and 1,500 (men) a day in which 80% of it consists of fat. You are allowed to add anything to your food that adds fat. Mayonnaise, avacado, bacon, eggs. This is all allowed.

Will this make you fat? Not even close. In fact, you will lose a lot of it. Brian makes it clear the only fat you should fear is trans fat and this is what you have to stay away from. 

One study explained in this section talks about 4 groups of people who were on a 1,000 calorie diet. One group only ate proteins, one only ate fats, one only carbs and the last one was a regular diet. 

The irony is that the group which was on the high fat diet lost the most weight. And remember, we’re talking 1,000 calories each.

The key is to keep carbs to a minimal. You are allowed up to 30 grams of carbs per day if you can’t hold on. There are also health benefits of a high fat diet.

Phase 4: Lasts until day 21 (9 days)

This is the easiest part of the diet. All it really focuses on is just eating under your BMR on a daily basis. There are different “aggression levels” during this phase with aggression being how much weight you want to lose.

Depending on how much weight you want to keep losing, you’ll eat under your BMR anywhere from 15%-30% meaning if your BMR was 2,000 calories a day, 15% would mean you could eat only 1,700/day. 

Experience the weight loss power of the 3 week diet.

Finishing the diet and eating anything you want:

Once you complete phase 4, you really can do what you like as long as you maintain the BMR rule. You can eat pizzas, burgers and anything you want. This can continue for as long as you want.

The 3 pound rule:

One thing that is mentioned is the “3 pound rule” which says if you gain 3 pounds back or more after the diet, go back and do one of the phases to get back on track. 

Other things about the diet:

The book itself is 96 pages long. The first 44 pages are Brian explaining many of the theories behind the plan. By page 45, you’ll actually get into the diet.

There is an optional step to the entire diet and that is intermittent fasting. For 24 hours every week, if you can avoid eating for just 1 day, you’ll speed things along. Brian says he does it 2 times a week.

For people who are really new to this and have never tried it, 18 hour fasts are also recommend and again if you start the fast after your last meal at night, it will be easier.

There are also 3 additional offers after you purchase the diet book itself, one is a recipe book, another is a support connection and the other is known as the “Final Chapter” which is supposed to help you plan long term after your diet is done.

These things are optional and I personally didn’t try them. I feel that the book is more than enough. Get your hands on the book right here.

The workout plan:

There’s a lot of chapters within this section, but some of the points mentioned is that you’ll be doing interval training workouts and a lot of the focus on the workouts is several things:

1. You will be exercising for about 20-30 minutes while you’re on the diet.

2. The focus of the workous is to keep burning off fat even while you’re dieting. Fat reduction is key.

3. You should aim to walk every single day.

4. The workouts don’t just burn fat, but are also aimed to sculpt the body and give you 6 pack abs.


  • Very fast weight loss results. Up to 30 pounds are possible.
  • Targets fat storage areas in the body.
  • You can eat anything you like after the diet is done (so long as you keep to the rule).
  • Not much exercise required.
  • The phases give you the best results, but you can stick to one of them if you like so there’s flexibility.
  • Only 21 days long.


  • Intermittent fasting can be tough for some people.
  • Working out, though short can also be tougher due to low carb eating/fasting.

3 Week Diet Score: 4 out of 5 stars.

4 stars

Excellent diet for fast results. There can be difficulties along the way, but it will get easier as you progress through each phase. Very powerful diet. Check it out!


Start losing stubborn fat quickly with the 3 week diet.

Conclusions on the 3 week diet:

Overall, this diet is very powerful, no question about it. But is it for everyone?

Well if you’re looking for fast results and you have no problems with fasting just once (at least) or once a week (at most), then you should be fine with this. If you are, you can skip the fasting part and focus on the other areas of the diet.

Remember, it gets easier. Brian has really cut it down into sections so the most difficult parts are handled quickly. This is what I really liked plus with the intermittent eating (which is technically optional), about half of you will sleep off making the process easier. Intermittent eating and fasting by the way isn’t all that difficult and it gets much easier the more often you do it. It will speed things up.

I say do this diet if you’re OK with intermittent fasting and really need fast weight loss results. Normally diets which aim to get fast results also have a high chance of the yo-yo effect happening. With this diet, that’s taken into consideration. The yo-yo effect will not happen if you follow this diet’s rules.

Get started here.

This means you can and will lose weight very fast and make sure it stays off. That’s a good diet. 

34 thoughts on “How The 3 Week Diet Will Make You Lose 23 Pounds of Fat in 21 Days.

  1. PRIA

    In Phase 2, Fasting, does it mean no water?
    I can stay without food but without water will be difficult.

    1. Vitaliy Post author

      No matter what kind of fast you do, you can always drink water Pria!

    1. Vitaliy Post author

      You should keep taking any medication while on the 3 week diet Joan. But with diabetes, you will need to ask your doctor about this diet first.

  2. Jessica

    Do you know if veggies are still ok during phase three? I am a bit confused by this phase. I know we are supposed to eat mainly fat, but I need fiber! Lol

    1. Vitaliy Post author

      Vegetables are not part of the third phase Jessica, but this period is very short and after this phase, you can go back to eating any vegetable you want.

  3. Katya

    What if a person has already a very low bmr for example 1300 kcals..

    1. Vitaliy Post author

      If it’s that low, you probably don’t even have to diet Katya. You should speak with a doctor to see if this is normal for you or if you need a supplement.

  4. Christine Abresch

    I have to lose 20 pounds and eat a heart healthy diet, I am taking blood thinners and anti clot meds along with statins to reduce blood cholesterol…..can I follow this plan?

    1. Vitaliy Post author

      Hi Christine, your problem appears to be more about health, not weight but there is a diet known as the DASH Diet which is considered heart healthy I think would suite you better, but of course, talk to a doctor!

  5. Linda

    This is a diet that I want to try, but dread the thought of not having any coffee for a week, since that is what kickstarts my day! Three weeks is not a long time to try out a diet, and from the looks of it so far it could be something I could actually live with, I like most of the foods listed, now I’m trying to see if I can get any results, thank you for the very detailed information.

  6. Madz

    Are there any specific foods that needs to be/ cant be eaten in phase 4?

    1. Vitaliy Post author

      There wasn’t a list for Phase 4, only that you eat less than your calculated BMR.

  7. Rebecca

    I’m on day 1 and was wondering whether I could take Hydroxycut Hardcore Elite in Phase #1 (as that contains caffeine and Yohimbe) and should I have the Whey Protein with with my meals when it demands protein? Or should these wait until Phase #3?


    1. Vitaliy Post author

      I would wait until phase 3 Recebba or even 4 when you won’t have to wonder if this or that food is allowed.

  8. TD

    I’m about to begin this diet, but I have a question. For the first week, you can have NO tea or coffee at all?

    1. Vitaliy Post author

      Hi TD, that is correct, no coffee is allowed for the first week.

  9. Holly

    Thank you for this post. Can you use the whey protein in the first phase for an acceptable protein? I’m in my car a lot for work and it would make life so much easier:)

    1. Vitaliy Post author

      Hi Holly, in phase 1, it is better to use proteins at their source (no powder), so I would not recommend any whey. Try to use hard boiled eggs or chopped pieces of chicken as protein substitutes for this part of the plan.

  10. Nina

    Thanks for this post. I have bought the book and I am on my day 5 (already lost 2kg). I am loving it! I love that it explains the science behind it. It is easy if you drink at least 3 liters of water every day. First week without a coffee is hard but still possible. Every time you have cravings, DRINK A LOT OF WATER, it helps a lot! Fasting i find easy if you do 12 am / 8pm 8 hours of window. Will update you on results.

  11. Laura

    The first day, are mushrooms the only vegy a person can have? I cannot stand mushrooms of any kind. Thanks

    1. Vitaliy Post author

      Hi Laura, there are many more choices than just mushrooms. You can eat from a wide variety (most vegetables).

  12. Keran Elizabeth Fynn

    Hi. Thanks for this. Really cleared up the little bits of confusion I had. Starting this in February. I know we have to use Fish Oil supplements but do you know where the Whey Protein comes in?

    I don’t want to have to spend so much money on something and not end up using it. Thank You

    1. Vitaliy Post author

      Hi Keran, there is no fish oil or whey required in this diet. Those are only things you may want to use if you’re either trying to build muscle or have joint problems. You can use them in the 3 week diet however. If you exercise a lot, take them before or after your workout.

      You also asked about phase 4 and eating breaking, yes it’s ok to do it as long as throughout the day, including breakfast as long as you remain under your BMR.

    1. Vitaliy Post author

      Hi Monica, you can use any of the sample foods in the phase 3 menu. For breakfast, maybe a few eggs and avocado, for dinner, you can also eat that and add some bacon. Chicken high in fat can also be used and if you fry something, use coconut oil, it is high in fat too.

      Phase 4 is easy, figure out your BMR, then eat under the recommended percentage. After phase 4 is complete, just continue that way.

  13. Peter

    Hi Vitality,
    I like the idea of a diet that has an after plan to stop you putting back on the weight you have lost. Phase 3 is interesting where you eat 80% of fats, I recently saw something on TV about this subject. Apparently eating lots of calories from fats will send a signal to your liver to burn off some of your body fat or energy reserves.
    Apart from the fasting this doesn’t seem to be too difficult and I am sure many people could be successful with this diet. It’s good to see the workouts are an integral part of the diet and not too demanding but necessary.

    1. Vitaliy Post author

      Thanks Peter, indeed every phase after the first one is easy to ease into.

  14. ike

    Hi Vitaliy. Phase 3 is the one which interested me most. You’re going to be eating a high fat/low calorie/low carb diet and ironically with what Brian explains and the studies he cites, I guess we can lose weight right now since its the only way to live long.This means you can and will lose weight very fast and make sure it stays off. That’s a good diet.

    1. Vitaliy Post author

      Most people become interested in the high fat section of the diet Ike and that’s because it just sounds way different than anything we’re used to hearing about diets, but you can look up the evidence and see that it’s real!

  15. Ben

    I don’t know about eating only vegetables, fasting, LOL! I guess it’s worth it, considering it’s only one day. Pain makes gain, and not weight gain!


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