What is the military diet?

Currently riding high in the diet stakes, the military diet claims to help you lose weight and fast, with weight loss claims of up to 4.5kg (10 pounds) in just one week. The other big bonus is there is no financial outlay with no book, supplements or exercise programme to spend your hard-earned cash on.


Despite its name, the diet has no links with any military or government body and is, in fact, known by other names including the ‘three-day diet,’ the ‘navy diet’ and the ‘army diet’. Apparently, the name was chosen to reflect the discipline and resolve needed to achieve weight loss, much like that demanded by the military.

The diet involves dividing your week into three low-calorie days, followed by four healthy eating, non-diet days. For the first three days you follow a set low-calorie meal plan for breakfast, lunch and dinner with no snacking. Your calorie intake for these days will be 1400, 1200 and 1100 calories respectively, although men are advised to add an additional 100 calories per day, in the form of protein rather than carbs.

Caffeinated drinks are included as long as no extra calories are added in the form of milk, cream or sugar. Artificial sweetners (other than stevia) are discouraged and alcohol is not permitted during the low-calorie days.

On the remaining four days of the week you are encouraged to eat healthily but continue to keep calories on the lower side – a suggested 1500kcals per day. During these four days there are no food groups restricted and you can include a snack. For those needing some inspiration, a ‘four days off’ plan is provided from which to select your meal and snack choices. Suggestions are that the plan may be repeated weekly until you reach your goal weight.

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Nutritionist Kerry Torrens says...

The calories permitted by the plan are lower than the average adult’s recommended intake. Food variety during the low-calorie days is limited and there is no guidance given on the inclusion of wholegrains which means followers are unlikely to get enough fibre, vitamins and minerals.

The plan includes a high number of processed foods including hot dogs, ice cream and crackers, which means it is likely to be high in salt, sugar and saturated fat. A diet reliant on processed foods has been linked with disturbances in gut health, including disruption of the gut microbiota and associated links to inflammation, metabolic disturbances and an increase in body fat.

Although the initial three days sets out what to eat, substitutions are allowed as long as the calories remain the same. This allows the diet to be adapted for vegans, those who are lactose intolerant or who need to follow a gluten-free diet.

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The plan claims it is effective because of the combination of specific low-calorie foods and metabolic boosters which have been chosen to increase metabolic rate and encourage fat burning. However, there is no scientific support for this. Although caffeine may be useful for weight loss, some studies suggest this is more relevant for those who are not overweight. Furthermore, grapefruit, which is included at one meal on one day of the three-day plan, is said to be included to support fat-burning, although studies in this area have found limited support for this.

Is the military diet healthy?

The plan fails to promote healthier eating habits or long-lasting dietary changes; instead, it advocates the inclusion of portion-controlled processed foods, including hot dogs and ice cream. Eating these foods on a regular weekly basis has the potential to cause metabolic issues and disrupt gut health. The three-day low-calorie plan fails to meet the recommended five-a-day and encourages sweeter fruits rather than health-promoting vegetables. Fibre levels are likely to be inadequate and micronutrient intake low.

Is the military diet effective for weight loss?

There are no studies to support the claims and efficacy of the military diet, although most people are likely to experience some weight loss as a direct result of the reduction in calories. But this is likely to be temporary, based on the execution of short-term willpower rather than sustainable healthy eating habits.

If you start the diet with a lot of weight to lose then you may well achieve the cited 4.5kg loss in a week. However, the amount of weight lost will be dependent on your personal circumstances. Much of this weight will be due to water loss rather than fat. This is because our bodies lose water when our glycogen stores start to decline, which typically happens when we restrict carbs and calories. Once normal eating patterns resume, you are likely to regain the weight you have lost.

Is the military diet safe to follow in the long-term?

For the average healthy person and for a short time only, the military diet is unlikely to do harm. However, if you were to follow the diet for any length of time, the limited selection of foods, low levels of vegetables and the lack of five-a-day is likely to put you at risk of nutrient deficiencies and the associated health implications.

Who shouldn’t try the military diet?

It is advisable to refer to your GP or healthcare professional before starting any new dietary regime especially if you are under 18 years old, elderly, have a pre-existing medical condition or are on medication.

If you are considering attempting any form of diet, please consult your GP to ensure you can do so without risk to health.

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This article was published 1 July 2020.

Kerry Torrens BSc. (Hons) PgCert MBANT is a Registered Nutritionist with a post graduate diploma in Personalised Nutrition & Nutritional Therapy. She is a member of the British Association for Nutrition and Lifestyle Medicine (BANT) and a member of the Guild of Food Writers. Over the last 15 years she has been a contributing author to a number of nutritional and cookery publications including BBC Good Food.


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