The 3-Day Diet – Does It Work? 8 Myths you need to know


Are you looking to lose up to 10 pounds in 3 days? Maybe lose upwards to 30 pounds in a month? Well if you believe all the hype of the 3-Day Diet, you can try your luck for quick weight loss.

The 3-Day Diet, also known as the Military Diet, is taking the web by storm right now because of its convenience and low cost. It goes by a number of different names like the Birmingham Cardiac Diet and American Heart Association Diet, but rest assure there is no company or group affiliation with this diet. But one thing is for certain, this high risk caloric restriction plan is one no nutritionist or dietician supports.

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Any diet plan that restricts or cuts out entire sources of vitamins, minerals, and nutrients are considered crash diets because of the malnutrition. Crash diets like this are fads and here’s a little outline of what each day of the diet consists of:

Day 1: 1400 Calories

Breakfast: One slice of toast with 2 tablespoons of peanut butter, half a grapefruit, black coffee or tea.

Lunch: One slice of bread or toast, 1/2 cup of tuna, black coffee or tea

Dinner: Three ounces of meat, one cup of green beans, half banana, one cup of vanilla ice cream

Day 2: 1200 Calories

Breakfast: One slice of toast, half banana, one cooked egg

Lunch: One cup cottage cheese, one hard boiled egg, five saltine crackers

Dinner: two bun-less hot dogs, one cup broccoli, half banana, 1/2 cup vanilla ice cream

Day 3: 1100 Calories

Breakfast: One slice of cheddar cheese, one small apple, five saltine crackers

Lunch: Once slice of break or toast, once cooked egg

Dinner: Once cup tuna, half banana, one cup vanilla ice cream

After the 3 days of the strict meal plan, the experts recommend for the next 4 days to consume a diet of 1500 calories of whole foods, that are low in carb and high in protein. Then at the start of the next week begin the 3-Day Diet again.[1]

This diet has the option to be a quick fix, or if someone is committed to calorie restriction it can be applied for longer stretches of time. But women are recommended to consume a minimum of 1200 calories a day and men at 1800, and this diet neglects those basic nutritional foundations. That’s one myth that is founded on fact, but don’t worry there’s 8 myths about the 3-Day Diet we’re going to explore and shine some light upon.

The 3-Day Diet makes a lot of claims to why it’s successful. And with this kind of calorie restriction, there will be movement on the scale. People who have participated in this diet and performed the three days accordingly did lose weight. But not because of fat burning properties the diet promotes. In fact, if there is increased metabolic rate as it claims to have, why do 80% of those who participate in extreme crash diets fail to sustain weight loss? Research has showed there’s a greater chance of binge eating and regaining nearly 150% of the weight back.[2]

8 Myths about the 3-Day Diet

1) Multiply your weight by 12 and that’s how many calories you burn in a day

I nearly spit my morning coffee out when I read this on the website. You don’t even have to be a registered dietician to know this claim is false.

Let’s put this logic to the test:

A marathon runner of 135lbs will burn 1,620 calories a day, whereas someone who lives a sedentary lifestyle and weights 300lbs will burn 3,600 calories a day.

Um, what?

For those who have greater lean muscle mass to fat ratio will burn more calories than someone who has more fat than muscle. It’s the foundation human physiology that muscle burns more calories. Body composition, anatomy, and endocrine system all play critical roles in how our body utilizes calories. Here’s an example, men typically burn more calories than women. That’s how anatomy plays a role in caloric expenditure.

2) Grapefruits promote fat burning

There is some truth to this myth. But the way that grapefruits are utilized in the 3-Day Diet do not harness the fat burning powers of the grapefruit. There’s a flavonoid in grapefruits, naringin, which helps with cellular breakdown of hyperlipidemia and plaque build up in the arteries. In a not so roundabout way, if you are obese grapefruits will shine it’s fat burning properties quickly. [3]

Grapefruits are low on the glycemic index, so they don’t negatively effect the blood sugar levels so for diabetics it’s a good fruit to incorporate into the diet. But eating 1/2 a grapefruit once a week on the 3-Day Diet does not promote the liver to kick into gear to engage in fat-burning mode.

To debunk that myth of the 3-Day Diet, a 2006 study from the Journal of Medicinal Food explored those who drank 8 oz of grapefruit juice or ate 1/2 a grapefruit before each meal lost an average of 3.5 pounds over the course of 12 weeks. [4]

3) 3-Day Diet will speed up your metabolism

The coffee in the 3-Day Diet will promote thermogenesis which does positively impact your metabolism.[5] But that’s about where the increased metabolism claim should end in this myth on the 3-Day Diet. Metabolism is a chemical process where the body needs to maintain, produce or breakdown substances to make energy available for cellular function.

The extreme caloric restriction of this diet will have a negative impact your metabolism. Well it’s simple, if you are restricting the consumption of calories, which are units of energy, your metabolism cannot work efficiently. Plus this diet doesn’t encourage exercising, and exercising is the best way to improve your metabolic rate. [6]

4) 3-Day Diet promotes high protein consumption to burn more calories

This myth on the 3-Day Diet has a little bit of truth. It does take more energy to break down proteins. If you eat a protein that is 100 calories, approximately 20-30 calories will be used in the digestion process. Proteins are made up of amino acids held together with peptide bonds and to break down the bonds the stomach has to work doubly hard compared to breaking down fats and carbs. [7]

The issue with the 3-Day Diet is the proteins within the diet plan: canned tuna, hot dogs, cottage cheese, etc. are processed. There’s also no guidance or options on what type to purchase. Like with the canned tuna, do you purchase white tuna in water or albacore in oil? Do you buy cage free eggs? Do you buy nitrate free hot dogs? And it appears that much of the information about the food combinations do not have any facts to back up the fat-burning properties.

If you tell me that a can of tuna, a banana and then a scoop of vanilla ice cream will be nutritious and increase my metabolism, I would scoff at you.

5) Your body will not go into starvation mode on the 3-Day Diet

The information circulating around about the 3-Day Diet has mixed responses about whether or not the body will enter into starvation mode. Starvation mode is when the body slows down metabolism because of the lack of calories, nutrients, vitamins entering the body. Bloating tends to be a common side effect of the body entering into starvation mode. [8]

When you deplete your body of what it needs to operate and function it quickly begins to break down proteins within the muscle. Which is called catabolism. So as you are losing weight, you’re losing muscle along with fat. Here’s how you will end up regaining the weight back:

-Muscles play a crucial role in the rate of burning calories and maintaining your metabolism.

-As you lose muscle, your metabolism will decline

-Less muscle means lower your metabolic rate

-Lower metabolic rate leads to increased weight gain once you’re off the diet. [9]

6) It’s one of the best natural diets

This myth has nutritionist and experts scratching their heads about the 3-Day Diet. If there is a natural spring of vanilla ice cream on this planet, I’m shocked there isn’t a full civilization built around it reaping the natural wonders of it.

There’s many option to consume healthy low-cal nutrient dense foods that do not consist of saltines, and hot dogs. This diet consists of a lot of refined carbohydrates and processed meats. Though, the website does provide “substitutions” for the foods highlighted on the meal plan.

The big component the creators of the website detail is replacing a food that is of equal caloric value. [10] What this diet consists of is reducing caloric intake and depleting the body of essential nutrients, which does not seem to emphasize it’s claims to “the best natural diet.”

7) Dieting makes you lose fat not water

It’s not uncommon to see lower numbers on the scale when you first start a diet. But this is not because of the instant fat burning properties diets promise. The instant fat-burning myth of the 3-Day Diet gets trampled when you look at the scientific evidence provided by the Mayo Clinic:

“During the first few weeks of losing weight, a rapid drop is normal. In part, this is because when you cut calories, the body gets needed energy initially by releasing its stores of glycogen, a type of carbohydrate found in the muscles and liver. Glycogen is partly made of water, so when glycogen is burned for energy, it releases water, resulting in weight loss that’s mostly water. This effect is temporary, however.” [11]

Once the glycogen storages are used and burned up by the body due to caloric and energy restriction, you begin to see side effects like dizziness, fatigue and irritability.

8) This is a three day diet

This is the biggest myth of them all. This is not just a 3-Day Diet. This is actually a diet that’s broken down into two parts. The first part is extreme calorie restriction for 3 days. To follow a diet that encourages the consumption of “natural foods” that promote “a fat-burning metabolic increase.”

The second part of this diet is the 4 additional days of only consuming 1500 calories of whole food, high in protein. This diet is to be rinsed and repeated for as many weeks it takes for an individual to reach their goal weight.

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[1] The Military Diet:
[2] UCLA Newsroom:
[3] Advances in Nutrition:
[5] National Center of Biotechnology Information:
[6] Muscle for Life:
[7] University of Wisconsin:
[8] Research & Reviews:
[9] The Mayo Clinic:
[10] The Military Diet
[11] The Mayo Clinic


About the Author Amanda Roberts

Amanda is a gym instructor and a diet and nutrition fanatic that has reviewed 100s of supplements for the benefit of consumers. She struggled with obesity 7 years ago and after losing more than 30lbs, dedicates most of her time in helping others achieve similar results and transform their lives. You can contact her via the "About Us" page.

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