Is it safe to eat 800 calories a day? (risks and benefits)

In this article, we will discuss the safety of eating 800 calories a day, what are the benefits and drawbacks of eating 800 calories a day and who can eat 800 calories a day.

The number of calories ingested by a person may vary depending on many factors, however, a minimum caloric and nutritional input is necessary to maintain health. Very low-calorie diets have benefits and side effects.

Is it safe to eat 800 calories a day?

Yes, it is safe to eat 800 calories a day, if the diet is being monitored by a dietitian or a medical assistant (1, 2). The diet should be preferentially prescribed by professional healthcare.

Monitoring of the patient is necessary during the entire treatment, especially at the beginning of the treatment and even in the period of body weight maintenance which follows the period of weight loss (1, 2).

Following a diet without proper supervision can lead to malnutrition, muscle loss and diseases, because to keep the body healthy, not only calories are necessary, but also specific nutrients, vitamins and minerals (3). 

When eating 800 calories a day is not safe?

Eating 800 calories a day is not safe for individuals with a normal body mass index (BMI), that is, for non-obese individuals (1). Normal individuals need an adequate amount of energy.

Inadequate energy intake can lead to undernutrition and malnutrition, loss of muscles and bone mass, the development of diseases, such as anaemia, skin problems and increased risks of infections (3, 5).

What are the benefits of eating 800 calories a day?

The benefits of eating 800 calories a day are the effective and rapid loss of body weight, a significant reduction of body fat, the reduction of blood pressure and the improvement of sugar levels in the case of diabetic patients (1, 2).

Obese patients can lose about 6 to 8 kg per month by following a low-calorie diet and the diet can be used for a short period of 24 weeks or longer periods of over 100 weeks (1, 2).

Losing weight is important especially in the case of obese individuals, as obesity leads to other diseases, such as diabetes, high blood pressure and higher risks of certain diseases, including heart and kidney diseases, and post-menopausal breast cancer (4).

What are the risks of eating 800 calories a day?

The risks of eating 800 calories a day are the side effects related to this low-calorie diet, which include fatigue, constipation, dry mouth, hypotension, hair loss, dizziness and headache, especially in the first weeks of the treatment (1, 2).

Another risk of eating 800 calories a day is the loss of motivation after a certain period, which leads to the regain of weight. Menstrual disorders and psychological side effects have been also reported as a risk of a low-calorie diet.

The risk of malnutrition occurs when the diet is made without medical assistance. The body needs minerals, vitamins and proteins (3). A minimum intake of carbohydrates is necessary to avoid loss of muscle lean mass during a diet (1, 2).

Who can eat 800 calories a day?

Individuals who need to lose weight, that is, obese and overweight individuals can eat 800 calories a day. This is because their body contains energy storage in the form of fat.

To lose weight, the energy intake must be lower than the energy consumption. By ingesting a lower amount of calories than your body needs in a day to maintain the daily activities, the body will need to consume the energy stores and burn fat.

The low-calorie diet is recommended for individuals with a body mass index (BMI) of above or equal to 30 and are at risk of cardiovascular mortality (1).


In this article, we discussed the safety of eating 800 calories a day, the benefits and risks of following a low-calorie diet and in which cases this diet is recommended.

If you intend to lose weight, look for medical assistance to reduce the risks and improve the results, as losing weight rapidly can have many side effects.

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