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3 Week Diet Review - 13 Things You Need to Know

Brian Flatt’s 3 Week Diet is a weight loss system based on various manuals. It says it can help you lose up to 33 pounds in just 21 days — so we had to know what the catch is. Some people reported results, but low-calorie diets like this one can often be too much for some.

Many 3 Week Diet users experienced low energy levels and intense discomfort, as well as other side effects. Our research team focused on the science and user reviews to get the full picture, then compacted all the facts for you.

3 Week Diet can be purchased through their Official Site.

3 Week Diet Readers: Noom is offering our readers a free trial, for a limited time. Click here for this special offer!

What is the 3 Week Diet?

The 3 Week Diet Program is a manual-based system created by Brain Flatt which is designed to help consumers lose body weight and body fat in twenty-one days.

It is a diet system with specific manuals focusing on certain aspects of weight loss. The program consists of four instruction-based manuals, including the:

  • Introduction Manual
  • Diet Manual
  • Workout Manual
  • Mindset & Motivation Manual

Consumers can purchase the entire set, which is also available as a digital download, and start working on their weight loss with an accurately-designed meal plan.

How Did 3 Week Diet Start?

Brain Flatt, a certified personal trainer and sports nutritionist, created the 3-Week Diet.

According to him, other weight loss programs or diet plans are more targeted towards a slow approach to weight loss and do not help the user in shedding stubborn stored fat.

Those fatty acids from the stored fat combine with glycerol molecules and form a triglyceride. Thus, the 3-week diet plan is specially designed to work on those triglycerides, which normal diet plans are not able to target.

3 Week Diet Customer Testimonials

3 Week Diet Claims

The 3 Week Diet claims that the user will be able to accomplish the following in twenty-one days, as compared to what other diet plan programs do in two to three months:

  • Lose 12-23 pounds of pure body fat
  • Lose 2-4 inches from the waistline
  • Drop 2-3 dress sizes
  • Increased muscle tone
  • Decreased cellulite
  • Improve metabolism
  • Get healthy skin and hair
  • Improve your cholesterol levels

What is Included in the 3 Week Diet Program?

The 3-week diet system consists of four books with a specific aim. There is an Instruction Manual book which focuses on science and techniques behind weight loss.

It provides details about nutrients which will be required and worked upon during this program.

The second book is the Diet Manual, which provides comprehensive details and provides a list of food to eat every day, the specific quantity of food to eat, and the timing to follow regarding the meals.

It’s a specially-customized weight loss plan targeted through a thorough meal plan.

The third book in 3 Week Diet plan consists of a workout manual which has special small exercises and workout plans which can be done in a gym or at home.

It also claims to have a unique Midsection Miracle Workout which has two special abs exercises to get six-pack abs.

The last book in the 3 Week Diet program is a Mindset & Motivational Manual, which includes a lot of motivational tips, tricks and secrets.

How Does the 3 Week Diet Work?

According to the 3 Week Diet Plan Program, there are four stages in this plan. The first stage contains a detailed explanation of what type of food users are supposed to eat.

It lasts for seven days and it specializes in eliminating toxins and clearing waste from the body. Certain foods which users can eat are as follows:

  • Chicken
  • Broccoli
  • Eggs
  • Spinach
  • Tomatoes
  • Turkey
  • Cabbage
  • Beef

The second stage makes the users do ‘The 24 Hour Fast,’ in which you are supposed to skip meals for one day. Certainly, this might be difficult for users who are doing this for the first time.

In the third stage, which lasts for two days, users are supposed to eat food with more calories and which might contain more than 70% fat.


This might sound contradictory to the claim of this product, though research proves that High Fat, Low-Carb diets help in losing weight.

The last stage is about adding more food to your daily intake schedule but with a precise calorie consumption chart.

The 3 Week Diet Plan also asserts that the users need not worry about gaining weight once again after losing it, as they can easily repeat Stage 1 and Stage 2 and can reduce their weight swiftly.

Does it Work

Does the 3 Week Diet Workout Plan Work?

In one of the reports by Times, nine weight loss and obesity expert doctors were asked about giving their advice on losing weight. All of them provided insights into what to eat, how not to focus on calories, the importance of commitment, etc.

The reviews and testimonials provided on the website to make it sound like a unique product (according to the users) which helped them achieve desired results. Plus, it helps that the 3 Week Diet instructions suggest exercising a minimum of 20 minutes, three to four days a week.


3 Week Diet Results

3 Week Diet Plan results have been mostly positive, according to their website.

Nevertheless, there is no direct scientific analysis available for this product.

Users have mentioned the importance of this being a ‘do it yourself’ sort of program.

It has helped consumers lose around seventeen to twenty-three pounds and includes food intake instructions, exercises, a calorie maintenance guide and necessary inspirational insights into weight loss.

However, users have also complained that there are no videos with these instructions and that a detailed video guide would have been beneficiary.


3 Week Diet Benefits

The 3 Week Diet program has exclusive money back guarantee. According to Brain Flatt, who is the creator of the 3 Week Diet Plan, if within sixty days users are unable to lose weight or are not satisfied with the system, then a ‘no questions asked’ refund will be issued.

Consumers can also get a glimpse of what exactly will be in the manual with a sample diet plan provided on the website.

Apart from that, the diet plan laid out in the 3 Week Diet System does not lay special emphasis on detox juices, teas or weight loss shakes. Instead, it includes a healthy and wholesome food.

Science also backed a whole foods diet. According to The Permanente Journal, “a whole-foods, plant-based diet is a powerful prescription for optimal health and the answer to health, health care, and physician wellness.”

Healthy organic food on a wooden board. Foods include cheese, tomato, bread, egg, salmon, radish, ham, and red peppers

All four manuals of the entire program are available as digital download pdf’s which can be read on computers, tablets, and cell phones.

Therefore, users don’t have to wait for the delivery of any product and can start right away with the plan as provided in the manuals.

Side Effects

Potential 3 Week Diet Side Effects

Immediate changes in food habits and diet plan can cause serious interference in body and mind mechanisms. According to a few reports, with sudden changes in dietary intake, the body may be severely affected.

Sudden modulation in diet intake may result in fatigue and constipation.

3 Week Diet Alternatives

The 3 Week Diet Program guarantees a weight loss of around twenty-three pounds within twenty-one days.

Nevertheless, certain instructions in the plan, such as the intake of caffeine, and a rigorous diet and exercising schedule, a one day fast, skipping breakfast and many other such specifications, may affect the user and might not provide them with a smooth weight loss program.

Therefore, we have also come up with alternatives related to the 3 Week Diet which overcomes the shortcomings of the 3 Week Diet Plan.

Eat Stop Eat

Eat Stop Eat is a 24 hour/7 days strategy-based diet plan which helps in weight loss. According to the creator, it increases fat burning hormones drastically.

Eat Stop Eat makes the user fast once or twice during the week. Users are not supposed to eat for 24 hours, but after that, they can resume their normal diet plan. During the fasting days, users can only have tea, coffee, water or diet soda.

ketosis and fasting

This practice is similar to intermittent fasting, though BioMed Central notes that more research is needed to determine its effects.

Weight Watchers Diet

The Weight Watchers Diet is a science-based point system guide. Users receive points based on the food they eat.

The guide supplies details to the users so that they eat more fruits and vegetables and eventually lose their weight. It also helps decrease their food intake, which previously consisted of food with ample amount of fatty acids.

It provides gentle guidance to the users so that their fruits, vegetables, and healthy food intake increases. With constant reminders and healthy food intake, consumers will surely lose weight in a specific time.

According to the research of U.S. News and World Report Weight Watchers has been on the top for eight years as the Best Commercial Diet Plan.

Also, the company offers weekly gatherings with weight loss experts to help monitor your food habits and weight loss.

Although no side effects have been discovered, the program is not available for children younger than thirteen years. Also, people with specific dietary requirements and supplements may not be able to participate in this program.

Trim Down Club

The Trim Down Club offers a detailed package which includes apps, recipes, resources, materials and relevant weight-loss tools.

The Trim Down Club provides a menu planner in which users choose their favorite food items. Based on the food items selected, the planner will furnish weekly, customized menu plans with precise proteins and carbs that will help them lose weight.

The Trim Down Club has amazing positive reviews on their website. According to them, the testimonials on their website have been written by genuine and actual users. They do mention to consult a physician before embarking on any diet change program.

The monthly subscription price might be an issue for some users. Also, the website does not claim to have any scientific proof of the results that the products offer.

Pros and Cons

3 Week Diet Pros and Cons


  • Detailed instructions
  • Money-back guarantee
  • You can eat normal foods
  • Offer tips on how to keep the weight off


  • Low energy levels with reduced caloric intake
  • Very restrictive for carbs and calories
  • Fasting can be physically uncomfortable
What Users Are Saying

What Users Are Saying

“Love it! Totally doable diet! Here goes losing at least 10 pounds and feeling better after I eat! So excited.”

“I don’t lose as fast as I want to. However, I have lost a lot of weight.”

“Editor!!!! This book is somewhat repetitive and not too well written. The advice was OK but no revelation or insights that aren’t in hundreds of other diet books.”

Bottom Line

The Bottom Line on the 3 Week Diet

Now the moment you’ve been waiting for: our bottom line on The 3 Week Diet. First off, we like that this diet is backed by a 60-day satisfaction guarantee and there are some dieter testimonials posted on the official website. However, we have some reservations about it because it’s not backed by any actual science. Also, we’re concerned about the unrealistic weight-loss claims, as well as the customer complaints we found posted on the web.

If you’d like to drop more weight, then we advise you to go with a diet plan that is backed by solid science, gives you plenty of bang for your buck and does not make unrealistic weight-loss claims.

Among the best weight-loss programs we’ve seen this year is one called Noom. Some of the amazing things this diet program offers include customized meal plans, 1:1 coaching, interactive support groups, extensive food logging, and more.

The makers of Noom are so certain of their weight-loss program that they’re offering a free trial, which is great!

Learn More About Noom »
3 Week Diet Review
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What are the side effects of the 3 Week Diet?

Some of the potential side effects of the 3 Week Diet include dehydration, muscle cramps, upset stomach, nausea and vomiting, as claimed by some followers.

What are the ingredients in the 3 Week Diet?

3 Week Diet ingredients include a four-phase diet plan, including the introduction, diet, exercise, will power, mindset and motivational manuals.

Does the 3 Week Diet work?

There’s information stating the program is scientifically proven, but we couldn’t locate one study showing the meal plan will help you lose weight.

How much does the 3 Week Diet cost?

The 3 Week Diet costs $47.

How should I take the 3 Week Diet?

You should take the 3 Week Diet in four phases. The first lasting six days. The second part starts on the seventh and runs to the eighth. Phase three starts on the ninth and ends on the eleventh. The final part begins on the 12.

Where can I buy 3 Week Diet?

3 Week Diet can be purchased using their Official Site.

Is the 3 Week Diet a liquid diet?

No, the 3 Week Diet isn’t a liquid diet. The program consists of eating whole foods.

Do I have to buy additional supplements on the 3 Week Diet?

No, you don’t need to buy additional supplements on the 3 Week Diet. The recommended products are not essential to the program.

Does the 3 Week Diet come with a guarantee?

The 3 Week Diet comes with a guarantee. If you aren’t satisfied with the product, you can return it within 60 days for a full refund.

3 Week Diet Reviews