You've been dieting for years, but you can't lose weight.
You're losing your mind trying to calculate how many calories you should consume.
Maybe it's because you're not taking your basal metabolic rate into account.
What is the basal metabolic rate?
The Basal Metabolic Rate (BMR) is the minimum amount of energy the body needs to maintain its vital functions at rest.
This energy is used for essential processes such as breathing, heart rate, digestion, body temperature regulation, and cell repair, even while we sleep or are completely inactive.
BMR is measured in calories and varies from person to person, as it depends on individual factors such as age, sex, body composition, weight, height, and genetics.
For example, a person with more muscle mass will burn more calories at rest than someone with a higher body fat percentage, since muscle tissue requires more energy to maintain.
How is the basal metabolic rate calculated?
There are different formulas that allow you to estimate BMR.
The two most common are:
Harris-Benedict Formula
Developed in 1919, the Harris-Benedict formula offers a reasonable estimate of basal caloric expenditure. You need to enter data such as weight, height, and age:
- BMR for women = 655.1 + (9.563 × weight in kg) + (1.85 × height in cm) − (4.676 × age)
- BMR for men = 66.47 + (13.75 × weight in kg) + (5.003 × height in cm) − (6.755 × age)
For example, a 32-year-old woman who weighs 70 kg and is 180 cm tall:
655.1 + (9.563 × 70) + (1.85 × 180) − (4.676 × 32) = 1507.88 calories
Mifflin-St Jeor Formula
The Mifflin-St Jeor formula is from 1990 and is therefore more up-to-date and also widely accepted by health professionals:
- BMR for women = (10 × weight in kg) + (6.25 × height in cm) − (5 × age) − 161
- BMR for men = (10 × weight in kg) + (6.25 × height in cm) − (5 × age) + 5
For example, the same woman from the previous example who is 32 years old, weighs 70 kg, and is 180 cm tall:
(10 × 70) + (6.25 × 180) − (5 × 32) − 161 = 1504 calories
Both formulas offer similar results.
You can also use online calculators that estimate your BMR by entering your personal data.
What does a BMR value mean?
BMR represents the minimum calories your body requires per day to survive at total rest.
For example, if your BMR is 1500, you need to consume at least 1500 calories daily to maintain your basic bodily functions.
This will help you calculate the amount of calories you should consume if you are in a calorie deficit, maintenance, or surplus.
This number does not include the energy spent doing activities such as walking, talking, or exercising.
How to use BMR to lose weight?
Knowing your BMR is crucial for establishing your daily caloric needs, especially if you are looking to control your weight.
Although BMR alone is not a diet plan, knowing it allows you to avoid reducing your caloric intake too much and thus preserve your energy levels and muscle mass while protecting your health.
3 steps to lose weight using your BMR
- Calculate your BMR. This will be the minimum number of calories your body needs daily.
- Calculate your total daily caloric expenditure. This includes the energy you consume in daily activities, work, and exercise.
- Create a calorie deficit. Subtract calories from the daily total to cause weight loss, always making sure you do not go below your BMR.
As a general reference, an average man needs about 2,500 calories a day and a woman, 2,000.
However, the most accurate thing to do is to make calculations according to your personal characteristics and your level of physical activity.
Importance of a moderate calorie deficit
A deficit of between 500-600 calories daily is usually effective and safe, allowing you to lose between 0.5 and 1 kg per week. This strategy respects the natural functioning of your body and is more sustainable than extreme diets.
It is not recommended to follow very restrictive diets (below your BMR) since they can affect basic functions such as brain metabolism, blood pressure, and heart rate.
What is considered a "good" BMR?
Honestly, there is no "good" or ideal BMR.
Your BMR is unique, determined by your genetics and your physiology. However, certain factors can influence its value:
- Muscle mass: the more muscle, the higher the BMR.
- Age: BMR tends to decrease with age.
- Sex: men usually have a higher BMR than women due to greater muscle mass.
- Body size: a larger person burns more energy at rest than a smaller one.
- External factors: illnesses, medications, nicotine, stress, and others can alter BMR.
Average BMR in men and women
In general terms:
- Men: between 1600 and 1800 calories daily
- Women: around 1550 calories daily
These figures are estimates. It is recommended to calculate your BMR in a personalized way.
How does age affect BMR?
Over time, BMR progressively decreases.
This is largely due to the loss of muscle mass associated with aging. Unless an adequate exercise routine is maintained, this decrease can cause weight gain if caloric intake is not adjusted.
It is common for body fat to accumulate with age, especially in the abdominal area.
BMR Summary
BMR indicates how much energy your body needs at rest to maintain vital functions such as breathing and digestion.
It is affected by factors such as age, sex, weight, height, body mass, and lifestyle.
Calculating your BMR helps you create a healthy and sustainable eating plan, adjusting your caloric intake without falling into excessively restrictive diets.
Consuming fewer calories than your BMR can have negative effects on your health and well-being.
Understanding your Basal Metabolic Rate is the first step toward smarter nutrition, effective weight control, and a healthy long-term lifestyle.
