What is the 3 day diet program?

October 9, 2025 •

4 min read

According to nutrition experts, a healthy rate of weight loss is typically 1–2 pounds per week, making the promise of losing up to 10 pounds in a week on the 3 day diet program highly questionable. This restrictive plan, also known as the Military Diet, is a fad diet that involves three days of very low-calorie eating followed by four days of less strict, but still calorie-controlled, eating.

Quick Summary

The 3 day diet program is a rigid, low-calorie plan designed for rapid weight loss, which is mostly water weight rather than fat. It follows a specific menu for three days, followed by four days of more moderate eating. The plan lacks robust scientific support and carries risks of nutritional deficiencies and metabolic disruption.

Key Points

Fad Diet, Not Military: The 3 day diet program, also known as the Military Diet, is a fad diet with no official connection to the armed forces.
Promises Rapid but Temporary Weight Loss: The diet claims rapid weight loss (up to 10 lbs in a week), but most of this is temporary water weight, not fat.
Based on Severe Calorie Restriction: The diet's effectiveness comes solely from its extremely low calorie intake (around 1,100–1,400 daily), not from any specific metabolic food combinations.
Associated with Significant Health Risks: Concerns include nutrient deficiencies, metabolic slowdown, fatigue, and a high risk of rebounding weight gain.
Unsustainable Long-Term: Its rigid and restrictive nature makes it unsustainable and prone to triggering yo-yo dieting cycles and unhealthy eating habits.
Healthier Alternatives Exist: Sustainable and healthier alternatives for weight loss involve a balanced diet, consistent exercise, and creating a modest calorie deficit.

Origins and Purpose of the 3-Day Diet

Despite its alternative name, the Military Diet, this program has no official connection to any military branch and is widely regarded as a fad diet. The name was likely adopted to imply the discipline and willpower required to complete it. Its primary purpose is to induce rapid, short-term weight loss by drastically cutting daily caloric intake. The diet first gained prominence in the 1980s, claiming quick weight loss and metabolic boosts. Any weight loss that occurs is primarily due to the severe calorie deficit, causing the body to shed water weight and glycogen stores, not significant body fat.

A Detailed Look at the 3-Day Meal Plan

For the first three days, the diet prescribes a very strict and low-calorie menu with no snacking allowed. A typical plan includes specific food items and portion sizes for breakfast, lunch, and dinner. Users can find detailed menu examples in the referenced documents. For the remaining four days of the week, dieters are advised to consume about 1,500 calories per day, focusing on lean proteins, whole grains, and vegetables to maintain their weight loss.

Scientific Analysis and Major Health Risks

There is no scientific evidence to support the diet's claims that specific food combinations boost metabolism. Nutrition experts highlight that the diet's effectiveness for short-term weight loss comes purely from its severe calorie restriction, which is unsustainable and potentially unhealthy.

Some of the most notable health risks include:

Limited Nutrient Intake: The restrictive nature of the diet can lead to deficiencies in essential vitamins, minerals, and fiber.
Yo-Yo Dieting: The low-calorie phase can trigger a cycle of over-restricting followed by binge eating, leading to rapid weight regain once the diet is stopped. This can create an unhealthy relationship with food.
Water and Muscle Loss: The quick weight reduction is primarily a loss of water weight and stored glycogen rather than body fat. This weight returns quickly when normal eating resumes.
Slowed Metabolism: Consuming fewer than 1,000 calories per day for an extended period can slow down the body's metabolism, making future weight loss more difficult.
Side Effects: Common side effects include fatigue, dizziness, headaches, and irritability due to low energy and nutrient deprivation.

Comparing the 3-Day Diet with Sustainable Weight Loss Methods


Feature	3-Day Diet (Military Diet)	Sustainable Weight Loss (e.g., Mediterranean Diet)
Pace of Weight Loss	Rapid, but mostly water weight; results are temporary.	Slow and steady (1-2 pounds per week); focuses on long-term fat loss.
Calorie Intake	Severely restricted for three days (~1,100–1,400 calories), followed by four moderate days (~1,500).	Moderately reduced, with a focus on a balanced, nutritious diet.
Nutritional Quality	Lacks variety and often includes processed foods like hot dogs and ice cream; risks nutrient deficiencies.	Emphasizes whole foods, including fruits, vegetables, whole grains, lean proteins, and healthy fats.
Effect on Metabolism	Can slow metabolism due to very low-calorie intake.	Supports healthy metabolism through a balanced, consistent diet and regular physical activity.
Long-Term Success	Unsustainable; high risk of weight regain (yo-yo effect).	Promotes healthy habits for lasting weight management and overall health.
Physical Activity	Discouraged during the restrictive phase due to low energy levels.	Encouraged as an integral part of a healthy lifestyle.

Conclusion: Is the 3-Day Diet Right for You?

While the prospect of losing a significant amount of weight in a short period can be tempting, the 3 day diet program's extreme calorie restriction and lack of nutritional balance make it an unhealthy and unsustainable option for most people. Any rapid weight loss is likely to be temporary water weight, with a high probability of regaining the weight once normal eating patterns resume. For sustainable, healthy weight loss and long-term well-being, adopting a balanced diet with regular physical activity, and consulting a healthcare professional is a far safer and more effective strategy. Focus on creating permanent, positive dietary changes rather than relying on a quick-fix crash diet.

For more information on balanced nutrition and sustainable weight management, consult resources like the Academy of Nutrition and Dietetics or talk to a registered dietitian.

How to Safely Lose Weight Instead

For those seeking long-term success, prioritizing balanced nutrition and consistent exercise is key. Instead of a restrictive three-day plan, focus on creating a modest daily calorie deficit, incorporating a variety of nutrient-dense foods, and building regular physical activity into your routine. This approach promotes fat loss while preserving muscle mass and supporting overall health. Developing healthy eating habits and addressing the root causes of weight gain are more likely to lead to lasting results than resorting to a short-term fad.

Frequently Asked Questions

The 3 day diet program, also known as the Military Diet, is a fad diet that involves three days of very low-calorie eating based on a specific, rigid menu, followed by four days of less restrictive eating.

The diet causes weight loss by dramatically reducing caloric intake over three days. The initial weight loss is primarily a result of losing water weight and glycogen stores, not actual body fat, which is often quickly regained.

No, the weight loss from this diet is typically temporary. The rapid weight loss is mostly water, and the restrictive nature of the diet often leads to regaining the weight, or more, once normal eating patterns resume.

This diet is not safe for everyone. People with health conditions like diabetes, heart disease, or a history of eating disorders, as well as pregnant or nursing women, should avoid it. It is always recommended to consult a doctor before starting any restrictive diet.

There is no scientific evidence that the 3 day diet improves heart health. Although it may limit some processed foods, the diet can be high in saturated fat and salt and lacks many heart-healthy nutrients.

Common side effects include fatigue, headaches, dizziness, and irritability, which are caused by the severe restriction of calories and nutrients.

No, despite its name, the diet has no affiliation with the U.S. military or any other military branch. The name is believed to imply the discipline needed to complete the strict plan.