Slim Female with perfect healthy fitness body, measuring her thin waist with a tape measure

Diet and Fitness: The 3 Week Diet Review

The road to achieving your dream physique can be stressful. With a surplus of online information related to dieting, weight loss, and sports nutrition programs, it can be hard to distinguish the actual facts from the myths.

Multiple diet plans are constantly being introduced by fitness gurus throughout the years. A specific example is The 3 Week Diet, a weight-loss program designed by Brian Flatt, a personal trainer, and nutrition coach.

Granted, the first question that everyone asks about every diet plan is: ‘Does it really work?’ Below, we’ll provide a review of The 3 Week Diet and give a concluding verdict.

What is this ‘3 Week Diet’ Program?

The 3 Week Diet is focused on increasing the intake of essential nutrients to promote proper functioning and optimal health. Anything nutritionally unnecessary is eliminated as they appear to slow or even stop the fat-burning process. The diet program also aims to address hormone imbalances that lead to weight gain or prevent weight loss.


According to online journalist Korin Miller of the Women’s Health Magazine, the 3 Week Diet works through a combination of a caloric deficit with intermittent fasting, a limited daily carb intake, exercise regimen, and supplementation.

Four Phases

There are four phases in The 3 Week Diet, and each one focuses on different factors. For instance, Phase 1 is for liver detoxification, Phase 2 requires 24-hour fasting, Phase 3 aims for fat fast, and Phase 4 involves your basal metabolic rate (BMR).

  • Phase 1: This is a seven-day period that focuses on cleansing the liver — the body’s main fat pumping organ. The 3 Week Diet recommends several vitamin pills or supplements to help with cleansing. In this phase, your diet will focus on vegetables and protein-rich foods.
  • Phase 2: The second phase requires you to fast for 24 hours. This fasting period begins from your last meal on the seventh day until the eighth day of the program. For your dinner on the eighth day, you’re allowed to eat whatever you want, but you still have to limit carb consumption through portion control.
  • Phase 3:  The third phase is called the ‘fat fast’ technique and starts from the ninth to the 11th day. It focuses on melting stubborn excess body fat, targeting the mid-section and hip region. During the fat fast period, your liver will be converting fat into fuel for your daily bodily functions.
  • Phase 4: The last phase begins on Day 12 and ends at Day 21 — a total of nine days. Your caloric intake will be based on an equation involving your Basal Metabolic Rate and weight loss goals.


Julie Upton, a registered dietician states that the website ( doesn’t offer adequate information in its promotion of The 3 Week Diet. In fact, you’ll have to pay first before you receive a detailed explanation of how the diet works.

Upton asserts that this fact makes The 3 Week Diet inadvisable for purchase. Moreover, she explains that losing a significant amount of body weight in three weeks will require a drastically low-calorie intake and necessitate an intense exercise routine.

Experts agree that a healthy weight-loss rate is one to two pounds a week, and losing more than this is unsafe and too rapid.

Key Takeaway

Fruits and juice with measuring tape

Any observed results triggered by The 3 Week Diet are most likely temporary. The diet plan is also generally unsustainable in the long run and may pose some health risks. You also have to take into consideration your individual daily calorie requirement, especially since The 3 Week Diet works primarily on caloric deficits.

If you have health concerns, it’s even more important that you consult a medical professional before starting any kind of diet plan.


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