What’s the deal with the military diet?

Fans claim the unusual food pairings of the military diet can help you lose 4.5kg in 7 days. Nutrition experts weigh in on the supposed science behind this fad.
Published 4 March 2021 | Updated 6 June 2024

Crash diets have always been rooted in a sense of extreme discipline. These super-restrictive weight-loss plans generally require you to slash calories (a.ka. kilojoules) and follow a regimented menu to get the promised results. One crash diet really leans into that spirit: The so-called military diet, which promises 4.5kg of weight loss in a week.

Does this rapid weight-loss plan work—and is it safe? Here’s everything you need to know before trying the military diet.

What is the military diet?

The military diet is a week-long eating plan that restricts your daily calorie intake to 1,000 to 1,500 calories, using a limited list of “approved” foods. It claims to produce rapid weight loss. Despite its name, the military diet was neither developed by the military nor used in basic training.

Nutrition experts, including registered dietitian Beth Kitchin, PhD, have pointed out that the origins of the military diet are unclear, with no specific person or institution claiming responsibility for its creation. This diet is similar to other fad diets that have gained popularity online in recent years, such as the three-day cardiac diet (which is different from a heart-healthy lifestyle).

How does the military diet work?

The military diet comprises of two phases. For the first three days, people follow a strict daily menu plan of roughly 1,000 calories. Some of the required food combos might strike you as odd—think ribeye steak with banana, and hot dogs with vanilla ice-cream. The pairings supposedly reflect foods that are “chemically compatible,” meaning they contain nutrients and/or compounds that benefit metabolism and blood sugar levels when eaten simultaneously. Problem is, the notion of “chemical compatibility” isn’t backed by real evidence. “The term is used to make this approach appear novel, but there’s little basis in science,” says registered dietitian Amy Gannon.

The second phase of the military diet, lasting four days, drops the prescribed meal plan—you can eat any foods you like—but you must stay at or below a 1500-calorie daily limit. The military diet allows for unlimited water and herbal tea, as well as two caffeinated, black beverages per day.

The diet concludes after seven days, though many followers do repeat cycles in hopes of continued weight loss.

The military diet meal plan

Like many crash diets, this plan prescribes small servings of very specific foods. The meals below aren’t merely suggestions—people are instructed to eat these items exactly. Here’s what’s on the menu:

Day 1

  • Breakfast: ½ grapefruit, 1 slice toast, 2 tbs peanut butter
  • Lunch: ½ cup canned tuna, 1 slice toast
  • Dinner: 85 grams grilled ribeye steak, 1 cup green beans, ½ medium banana, 1 small apple, 1 cup vanilla ice cream

Day 2

  • Breakfast: 1 egg, 1 slice toast, ½ medium banana
  • Lunch: 1 cup cottage cheese, 1 hard-boiled egg, 5 crackers
  • Dinner: 2 hot dogs (no bun), 1 cup broccoli, ½ cup of carrots, ½ medium banana, ½ cup vanilla ice cream

Day 3

  • Breakfast: 5 crackers, 30 grams cheddar cheese, 1 small apple
  • Lunch: 1 fried egg, 1 slice toast
  • Dinner: 1 cup canned tuna, ½ medium banana, 1 cup vanilla ice cream

Days 4 through 7

During these four days of the military diet, you can eat and drink whatever you like, as long as you consume no more than 1500 calories each day.

Military diet substitutions

Some online postings about the plan suggest replacement foods for people who are lactose-intolerant or who are following a vegan, vegetarian or gluten-free diet. For example, people following a vegan diet are commonly advised to substitute a couple of tablespoons of hummus and half an avocado for tuna and meat.

In theory, swaps should contain roughly the same number of calories as the eliminated food, but Gannon notes that recommendations don’t always match up. Half an avocado can have three times as many calories as a cup of canned tuna. Even if you overlook the confusing swaps for special dietary considerations, the military diet is rigid and restrictive, which can make the plan challenging to follow, Gannon says.

Military diet benefits: Fact or fiction?

Supporters of the military diet swear by its results, but the scientific evidence doesn’t exactly stack up. Here’s a closer look.

Claim 1: Promotes rapid weight loss

Sure, lots of people might notice a difference on the scale when they complete a cycle of the military diet. That being said, “there’s no magic here,” Dr. Kitchin notes. Any extreme, restricted-calorie diet can lead to weight loss. The initial kilos people shed on crash diets—this one included—often reflect the loss of water weight, Dr. Kitchin explains. When the body runs out of fuel from food, it taps into glycogen stores in the muscles and liver for energy. Since glycogen is bound with water in the body’s tissues (about 3g of water for every 1g of glycogen), people lose water weight as they go through that supply. Generally, water weight returns when normal eating patterns resume.

Claim 2: Won’t slow metabolism like other diets

Good-quality studies of the military diet don’t exist, but there’s nothing in the available evidence to suggest the plan sustains an extra-speedy calorie burn, Gannon says. Your metabolism—a collective term for the many processes that convert food and nutrients into energy and building blocks the body needs—largely contributes to basic functions like breathing and blood flow. All other things being equal, smaller bodies require less energy to operate, so a person’s daily rate of calorie burn actually tends to dip when their weight goes down. This promotes the importance of having a solid maintenance plan in place after reaching a weight loss goal, which the military diet doesn’t offer.

Claim 3: Burns fat

There is zero scientific evidence for this one to date. “There is nothing specifically about the military diet that would help you burn fat more than other diets,” Gannon says. After the initial loss of water weight, any diet that causes you to lose weight will inevitably burn fat—along with some muscle—for energy.

Claim 4: Controls blood sugar swings

Some fans of the military diet contend that the plan’s food pairings—like toast with peanut butter—can prevent harmful “spikes” in blood sugar. The thinking behind this claim is that when you eat carbohydrates with some mix of fats, fibre, and/or protein, the carbs are less likely to cause a spike in your blood sugar. But here’s the thing, blood sugar swings aren’t a concern for most healthy adults to begin with, Gannon says. Although getting a balanced mix of macronutrients can help make meals more satisfying, there’s no research to suggest the military diet delivers special protective benefits concerning blood sugar regulation.

Claim 5: Melts 15kg in one month

Beware of blanket promises about the kilos you’ll lose. The amount of weight a person loses while following any given eating plan depends on personal factors such as age, activity level and starting weight. Moreover, health experts generally agree that trying to lose 0.5kg a day isn’t safe or sustainable. “If you make dramatic changes and then go back to your old habits, the weight will come back on,” says Amy Jamieson-Petonic, a registered dietitian and nutritionist. WW’s general guidelines, recommends setting a weight-loss goal of 0.5 - 1kg per week (not per day!).

Is the military diet safe?

Severely restricting calorie intake and shedding weight rapidly can negatively affect mood and mindset—and over time, may impact overall wellbeing. “I would be very concerned with long-term health,” Gannon says, of people who follow the military diet for prolonged periods. Potential risks may include:

  • Inadequate nutrient intake: The first three days of the military diet are low in wholegrains, fruits, vegetables and heart-healthy fats. Repeat for multiple cycles over time, and you may end up falling short on key nutrients. “A healthy eating pattern includes all of these foods,” Jamieson-Petonic says. “Long-term restriction may lead to deficiencies in vitamins A, B, C, D, E and K.”
  • Major hunger and fatigue: Dr. Kitchin has a warning for people who decide to take the plunge with this plan, “be prepared to feel starved and weak.” The military diet is very low in calories, which can leave the body low on fuel and bring on complaints such as fatigue, sweating, irritability, light-headedness and headaches.
  • Constipation: The military diet skimps on high-fibre foods such as wholegrains, fruits, and veggies, which are important for adding bulk to stool and keeping you regular. “Inadequate fibre intake can lead to constipation,” Jamieson-Petonic says.
  • Weight cycling: While you may initially lose weight on the military diet, you’re likely to put it back on once you resume your normal eating regimen. Alternating between periods of weight loss and gain increases the likelihood of future weight gain and may increase the risk of heart disease, stroke and heart attack, according to multiple studies.

The upshot: Should you try the military diet?

Most claims behind the military diet are not supported by scientific evidence. While it’s possible for a person to lose weight on this week-long eating plan, any weight loss is likely the result of extreme calorie restriction—and not some special synergy in the diet itself, nutrition experts say. What’s more, following a restrictive eating plan for an extended period of time is not sustainable for most people and may raise the risk of certain health concerns. Lasting weight loss generally happens through developing and maintaining healthy eating habits and lifestyle choices over time. This seven-day crash diet just doesn’t deliver.