Is Eating Below Your BMR Harmful To Lose Weight?

The central theses

  1. Many people claim that fewer calories than your basal metabolic rate (BMR) “damage” your metabolism and make losing weight much more difficult.
  2. A low-calorie diet of any kind (above or below your BMR) can lower your metabolism slightly and increase your risk of muscle loss, but there is nothing inherently bad about eating below your BMR.
  3. Read on to learn what happens to your body when you eat below your BMR, why eating below your BMR doesn't affect your metabolism, and how fast you should try to lose weight.

The idea of ​​losing weight slowly is about as appealing to most people as slapping a wet fish in the face.

That said, most of the people want to lose weight as soon as possible.

Of course, if you want to achieve drastic weight loss, you also have to take more drastic measures when it comes to it Calorie restriction.

For example, many people in search of lickety-split weight loss adopt very low calorie diets, often eating only 1,000 to 1,500 calories a day.

And while this leads to rapid weight loss, some people say it is bad for your health as well. In particular, they claim that problems really start when you eat less than you do Basal metabolic rate (BMR).

Your BMR is a mathematical estimate of the total number Calories Your body burns every day to keep your organs alive.

That said, it's an estimate of the absolute minimum number of calories your body needs maintain Basic vital functions like heartbeat, breathing, hormone production, etc.

Eating less than your BMR, some people warn, and you will force your body into "starvation mode", fueling your metabolism, making your hunger soaring, and affecting your ability to lose weight (possibly permanently).

But is that true?

Will crossing this physiological tripwire really cause your hormones and metabolism to mess up?

Let's find out.

Why People Think Eating Less Than Your BMR Is Unhealthy

According to people in many weight loss circles (especially online forums), the following happens to your body when you eat fewer calories than your BMR:

  • Suddenly your body no longer has enough energy to support basic organ function.
  • To stop your impending death, your body goes into "starvation mode" – your metabolism drops, you become sluggish and sluggish, and weight loss slows to a creep or even stops.
  • Like the battle with quicksand, the more you restrict your calories, the deeper you sink into starvation mode. Keep this up long enough and you will permanently scar your metabolism, making it a lot harder to lose weight in the future.

There are plenty of anecdotes from people who claim this is why they tried and failed to lose weight, and as with Jacob Marley Admonitions to Ebenezer Scrooge in A Christmas song, warn others that the same thing can happen to them if they are not careful.

Contrary to Marley's admonitions, however, this is really nonsense.

The truth is, eating under your BMR is not inherently bad – it doesn't harm your metabolism, put your body into "starvation" mode, or make it difficult lose weight.

Let's take a look at why.

Summary: Despite what many people have said, eating below your BMR doesn't harm your metabolism, nor does it make losing weight difficult.

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The reason it is safe to eat below your BMR is simple: even though the BMR is roughly the minimum number of Calories Your body has to sustain life; you don't necessarily have to get these calories from food.

For example, let's say a man named Josh has a BMR of 1,600 calories (pretty normal for someone on average Body composition).

Every day he burns an additional 800 calories exercise, digest the food he eatsand various activities he does every day (known as Thermogenesis without physical activity or NEAT) like Walk into the office, typing on his computer and drumming his fingers on his desk.

Josh gets to the point Total daily energy consumption (TDEE) is 2,400 calories per day.

One day Josh decides to lose weight quickly and reduces his caloric intake to 1,400 calories a day – 200 calories below his BMR.

Source horreur!

According to many people, this is when the physiological claxons begin to boom and his body slips into starvation mode due to lack of energy.

The reality is much less dramatic.

What really happens is Josh's body is shedding a little more body fat to provide enough calories to support his BMR – just as it is shedding body fat to provide the calories it burns during exercise, NEAT, and so on.

That said, Josh's body (and your body) doesn't consider BMR to be some kind of biological rubicon that should never be crossed. If you eat fewer calories than your BMR, your body will make up the difference by “drawing” more calories from your body fat stores, and everything will keep going.

In fact, research shows that if you do lift weights If you have a lot of body fat to lose, you can eat well below your BMR while losing fat and not experiencing any metabolic slowdowns (at least for a few months).

For example a study carried out by scientists at West Virginia University found that untrained, obese people lift weights and eating 800 calories a day (with just 80 grams of protein), lost 32 pounds of fat in 12 weeks and maintained practically all of their muscles.

In addition, not only did they avoid “starvation mode”, but also their resting metabolic rates elevated throughout the study (probably thanks to their new training plan).

In other words, even though these people ate around half their BMR, they saw their metabolic rates spike.

Read: You should be using a protein that is quickly modified to lose weight?

It has to be reiterated that these people were very overweight and probably didn't want to stick to this diet long term, but the results suggest that eating below your BMR is affecting your metabolism.

Despite the spread of the myth that "eating below your BMR is bad for you", no studies have shown that eating below your BMR is uniquely bad for your metabolism.

Summary: When you eat fewer calories than your BMR, your body uses the energy stored in body fat to make up the difference. Hence, eating below your BMR isn't all bad for your metabolism.

Any weight loss (temporarily) slows down your metabolism

Effects of eating under bmr

Any amount of Weight loss usually causes a slight decrease in metabolic rate, although it is nowhere near as significant or long-lasting as many people believe.

This is true regardless of whether you are eating under your BMR or not.

An outstanding example of this is a study conducted by scientists from the Norwegian University of Science and Technology, in which 171 overweight women ate only 800 calories a day (about 400 to 600 less than their BMR) until they achieved healthy health Body mass index.

Did this "destroy" your metabolism?

No – the researchers found that participants' metabolic rates only dropped about 50 calories per day by the end of their diet, and had essentially fully recovered a year after losing weight.

These results are consistent with several other Studies who have shown that the metabolic decline associated with dieting, including long periods of very low calorie diets, ranges from less than 5% to about 15%.

Contrary to what many "experts" say, this change in metabolic rate has nothing to do with "metabolic damage".

Scientists have known for decades that dieting temporarily inhibits metabolism and that doing so can make weight loss difficult (but not impossible).

They don't call this effect metabolic damagealthough. Instead, it's called metabolism Adaptation.

If you want to understand how these terms differ and everything else you need to know about "Metabolic Damage" and "Starvation Mode", read this article:

"Metabolic Damage" and "Starvation Mode" exposed by science

While eating below your BMR isn't just harmful to your metabolism, any kind of calorie restriction will make it slightly smaller.

This is an important point to remember as many people feel as long as they are eating over Because of their BMR, they don't suffer from the ill effects of dieting, but this is also wrong.

You can still experience metabolic slowdown, Muscle loss, fluctuating hormone levels, increased hunger, Loss of libido, compromised immunity, Nutritional deficiency, and Menstrual irregularitiesas well as a variety of psychological pitfalls, including depression, lethargy, and irritability when eating above your BMR.

Take yours, for example TDEE is 3,000 calories per day and your BMR is approximately 1,800 calories per day.

If you are already relative lean (research shows that very overweight people are more resistant to metabolic waste and muscle wasting) and you start eating around 2,000 calories a day. You could still lose muscle mass and reduce your metabolism even though you are eating 200 more calories than your BMR.

Basically, cutting your calorie intake heavily has a price, but whether you are eating under BMR or not, it does. Eating under your BMR is no “more dangerous” than eating over it.

In fact, I would argue that the Hullabaloo above the meal, under your BMR, lulls people into a sense of false security.

Just limit your calories, don't eat below your BMR and you will get the body you want. is an engaging but simple attitude.

While reducing calories is important, if you don't, you will likely not be happy with the way your body looks lift weights, Follow a high protein diet, and eat a healthy diet. In addition, you can "get away" with restricting your calories (even below your BMR) using these other weight loss "tools".

Summary: Limiting your caloric intake usually results in a slight, temporary drop in your metabolic rate, whether you are eating above or below your BMR. Eating below your BMR is not inherently “more harmful” than eating above your BMR.

How fast to try to lose weight

what is bmr

Instead of using your BMR to determine how many calories to eat, look at yours TDEE.

As you will remember, TDEE stands for Total daily energy consumptionand it's a mathematical estimate of how many total calories you will burn during the day.

So if you eat over your TDEE, you will increaseIf you eat near your TDEE your weight will stay the same and if you eat below your TDEE you will stay the same lose weight.

As you now know, eating below your BMR isn't inherently bad, but eating significantly fewer calories than your TDEE can cause some negative side effects.

The biggest problem with low calorie diets is that they exist a border how much body fat you can burn per day before your body starts breaking down muscle tissue for energy. In particular, muscle loss in most people tends to raise their heads when they limit their calories to less than about 75% of their TDEE (about 25% calorie deficit).

Read: How Fast Can You Lose Fat Without Losing Muscle? (According to science)

Now, it's worth noting that this tends to be above most people's BMR. Hence, it is technically correct to say that in general you don't want to eat fewer calories than your BMR. However, this is not because something is inherently wrong when you eat below your BMR, but rather because you are on a very low-calorie diet overall.

The only exception to this rule would be people with quite a lot of fat to lose (men with 25 +% body fat and women with 35 +% body fat) as they can lose fat faster without encountering the same problems.

Read: The Complete Guide to Safe and Healthy Fast Weight Loss

As you recently learned, research shows that these people can eat well below their TDEE (even below their BMR) without losing muscle or lowering their metabolic rates.

Summary: If you want to lose fat quickly without losing muscle, craving cravings, or significantly reducing your metabolism, you should maintain a calorie deficit of around 20-25% (75-80% of your TDEE).

The bottom line when eating under your BMR

The idea that eating below your BMR is bad for your metabolism is well established in the fitness arena, but it's wrong.

In reality, your body reacts to food below your BMR the same way it reacts to any kind of calorie restriction – it simply breaks down more body fat to keep your organs energized.

Therefore, eating below your BMR is not inherently bad or unhealthy.

Even so, any type of severe, prolonged calorie restriction can cause problems, regardless of whether you're eating above or below your BMR. In particular, you generally want to eat no less than 20 to 25% less than your Total Daily Energy Expenditure (TDEE), as this can lead to muscle loss and worsen metabolic slowdowns.

So, ultimately, eating below your BMR isn't inherently bad, but you generally want to avoid any low-calorie diet of any kind.

If you want to lose weight without encountering metabolic hobgoblins, starvation, or muscle loss, try to keep a calorie deficit around 20-25% below your TDEE.

If you enjoyed this article, please share it on Facebook, Twitter or wherever you want to hang out online! 🙂

What do you think of eating under your BMR? Do you have anything else to share? Let me know in the comments below!

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