Do You Lose Weight in a Coma? (How BMR Plays a Role)


You might have wondered, do individuals in a coma lose weight? How is this even possible?

Yes, you do lose weight in a coma, because you are likely consuming less calories than you are burning, and will likely be fed by an artificial route with formula that is calculated for you by a dietician.

The purpose of this article is to show the impact that the body’s basal metabolic rate can have on losing weight, and why it is so important.

Let’s get into it.

Do You Lose Weight in a Coma?

Yes, a person in a coma does lose weight, this is due to the fact that a comatose patient in a prolonged comatose state will need to be fed artificially with a formula that is calculated specifically for them containing vital nutrients.

A coma is simply defined as a state of prolonged unconsciousness.

A comatose state can be caused by traumatic brain injury, brain tumors, stroke, or even drug overdose. A coma can also be medically induced as a means to protect the brain and allow for healing.

When a person is in a coma, they obviously do not have the ability to consume food on their own. However, they still have the ability to digest food. Bodily processes are intact and functioning.

Digestion in a Coma

In a comatose state, brain activity is decreased and the person might even require mechanical ventilation to help them breathe. While reflexes like coughing and swallowing may be reduced, the digestive system is still working.

If the person is in a comatose state for a prolonged period of time, this patient will need to be fed in an alternative manner. This will consist of being fed through a gastric tube or receiving nutrients through a vein (Total Parenteral Nutrition or TPN).

When dieticians in a hospital setting are calculating the formulas for feeding these types of patients, they usually do not calculate the calorie and nutritional requirements to maintain obesity or gain even more body fat.

These formulas will be calculated to allow for a slow and steady weight loss of about a few pounds a month, if the person is obese. This ensures that the person will not lose too much weight and prevent proper healing and recovery.

These formulas will also contain vital nutrients inside to prevent malnutrition and also make sure blood sugar is within normal range.

The Science Behind Losing Weight in a Coma

When someone who is overweight is in a coma, they are going to be consuming far less calories than they usually do in their daily routine.

The comatose person is not able to eat, move, talk, or do anything really at this point. This person will essentially be relying on their basal metabolic rate alone because they are not actively moving.

For someone who is obese, they are obese because they are routinely consuming calories ABOVE their maintenance calories, or basal metabolic rate. A person in a coma cannot do this.

When someone consumes an amount of calories that exceeds the amount of calories their body burns on a daily basis, they will gain body fat.

Once the person is at this obese weight by overeating, their BMR will actually increase because it requires more calories to sustain the body’s processes at this increased weight. There is increased body mass, which requires more energy on the body’s part to maintain vital functions.

This means that this person will need to be eating this higher amount of calories every day just to maintain this higher weight, if they eat more than this amount, they will continue to gain more and more.

This is why obesity can be a vicious cycle and once someone starts overeating, it is easy to keep gaining and gaining.

How Many Calories Does a Comatose Patient Need?

Calories required for a coma patient varies, based on their current weight, gender, and general medical conditions.

The calorie content and the amount of calories set as intake for these patient are set by hospital staff including medical doctors and dieticians specialized in patient care.

There are many factors at play and setting the calorie amount of formula as well as nutrient contents needs to be done by a specialized individual such as a dietician to make sure healing is not effected.

If the patient loses too much weight during the course of the illness causing them to be comatose, proper healing can be effected.

There also many other health history factors at play too. For example, a person with diabetes will not be fed the same way as a person with no medical history.

A person with renal disease would also need a different diet than a person without renal disease.

The Impact of Coma on the Metabolic Rate

A individual who is in a coma will have a decreased metabolic rate.

Let’s take a look at this study amongst general critical care patients and patients put into a barbiturate coma, which is a medically induced coma.

The medically induced barbiturate coma group had a lower resting metabolic rate than the control group that remained lower even after adjustment for predicted healthy metabolic rate and maximum body temperature.

So you may ask, if the metabolism amongst coma patients is slowing down, how are they losing weight?

This just shows the importance of calories in vs. calories out.

When we decrease the amount of calories consumed, our body will lose weight, even if we do not have a super fast metabolism.

While it may be a slower weight loss than someone with a fast metabolism, it is still weight lost.

Yes, having a fast metabolism is great, but this does not mean you can’t lose weight and burn body fat with a slower metabolism.

If someone was consuming 3,000 calories per day through their diet but are now in a coma, they are no longer going to be consuming this amount of calories, because their calorie intake will be monitored and calculated for them.

Their slower metabolism in this case is not changing the fact that they are burning more calories than they are consuming.

Just because they are in a comatose state, does not mean they are not still burning calories. They are burning calories every single minute of the day because the body uses energy to keep itself alive, even though they are unconscious.

Coma and Basal Metabolic Rate

Comatose patients have a functioning basal metabolic rate just like a person who is awake and functioning.

Just because the person is comatose, their body is still maintaining processes like pumping blood to vital organs, oxygen exchange, kidney function, etc.

Using this example of a comatose patient having the ability to burn calories and lose weight while not even moving is a way to show you that BMR and TDEE matter, and it is important to base your calorie deficit around the BMR or TDEE.

In fact, 60-75% of the calories you burn every day come from your BMR alone, not from exercise.


So while exercising can promote cardiovascular health and muscle building, it is possible to lose weight simply by consuming a daily amount of calories that is 300-500 calories below your BMR.

Your TDEE is made up of your BMR PLUS the exercise you perform. If you are not a person that does much exercising, you can choose to simply focus on your BMR.

Here is a helpful calculator to calculate your BMR and here is one for calculating TDEE.

How Much Muscle do you Lose in a Coma?

There is no way to determine how much muscle someone in a coma will lose exactly, but it is common to lose muscle mass in a comatose state because the muscles usually used are not being utilized, which will cause atrophy.

When a person is in a coma, the healthcare providers will assist to do passive range of motion exercises to try to prevent this, but some muscle loss is unavoidable.

This is very important to mention, because while a person who is in a coma will lose weight, it may not be all fat. They could be losing muscle as well.

It is also important to mention that when losing body fat, we want to avoid losing muscle at all costs. Muscle mass is important and we want to keep the mass we do have.

A more muscular body will burn more calories at rest than a body with no muscle. This is because muscle tissue is more metabolically active than fat.

For example, 20 pounds of muscle would burn 60-100 calories in a day spent at rest, while 20 pounds of fat would only burn 20-30 calories.


Comatose patients often lose weight because they are consuming less calories than their body is burning over time.

It is also unfortunate that they may have some muscle loss as well by route of muscle atrophy, which will decrease their overall weight.

I am not saying you should EVER try to become a comatose patient, I am just using this example to show that the BMR and calories in vs. out are two powerful tools, and they are all that is required for decreasing body fat.

Even in a comatose patient, the basal metabolic rate is still at work burning calories, this is why it is important that the patient’s nutritional and caloric intake is highly monitored.

Because of these tools, you can lose weight through a healthy diet with a calorie deficit alone. You do not need to do cardio to see results.

However, if you do decide to get some extra movement in or some strength training, it will only boost your progress. You should do what you feel comfortable with.

If you want to lose weight in a healthy way, just create a healthy calorie deficit and you will see results.

If you need help creating your own calorie deficit, please check out the post below.

Related Post: Eat Whatever You Want in a Calorie Deficit