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  • Elianni Gaio & Marselo Zampietro

How a Restrictive Diet Actually May Not Help Lose Weight - Part I

How a Restrictive Diet Actually Mayt Not Help Lose Weight

The number of calories that a person needs varies according to several factors, and monitoring caloric intake is an important challenge for maintaining individual health and well-being.

In reality, we all know the harmful health effects of excessive caloric consumption, but few people understand that by restricting our daily calories we’re harming our health.

So, it is crucial to understand that both extremes such as eating too many calories or excessively limiting the number of our daily caloric intake have its danger in our health and well-being.

The fact is that reducing our caloric intake may not help lose weight and can put us at risk of muscle loss among a series of other problems such as hormonal imbalances, blood sugar imbalances, cravings, sleep problems, mood, fatigue and lack of energy, weight gain, etc. (1, 2)

It is critical not just identify but also correct any nutrient imbalances (macronutrientes and micronutrients) in our diet. And the purpose of this article is to explain how to calculate an estimative of the number of calories needed to support our vital organs and metabolism.

So, let’s begin.

How do we know how many calories our body needs daily?

Basal Metabolic Rate (BMR)

The basal metabolic rate is the amount of energy or calories that our body needs to maintain our vital functions such as: our breathing, blood circulation, control body temperature, nerve functions, among others. In addition, our organs also consume energy to function, and the organs that consume most of our energy are the brain, the central nervous system and the liver. And even when we are at complete rest, or sleeping, our organs and metabolism need energy in order to function. (3)

The first step to correct nutrient imbalances is: How to calculate our Basal Metabolic Rate (BMR), which determines the minimum amount of energy or calories we daily need. And there are several formulas used to calculate our Basal Metabolic Rate (BMR). One of the most reliable is called the Mifflin -St Jeor equation that you see below:

Basal Metabolic Rate - This is the equation (different for men and women)

BMR (kcal / day) = 10 x weight (kg) + 6.25 x height (cm) - 5 x age (y) + s (kcal / day),

The letters you see at the end of the formula represents a variable between men and women:

  1. for men add 5 (s = +5)

  2. for women, reduce 161 (s = -161)

As example:Calculating BMR for females:

Ana Carolina

1. Height in centimeters –170 cm (if your height is in inches, convert it to centimeters multiplying by 2.54)

2. Weight in kilos - 60 kilos (if your weight is in pounds, convert it to kilograms by dividing by 2.2)

3. Age - 55 years

Applying the Basal Metabolic Rate equation:

BMR = (height in centimeters x 6.25) + (weight in kilograms x 9.99) - (age x 4.92) - 161

BMR = (170 x 6.25) + (60 kilos x 9.99) - (55 years x 4.92) - 161

BMR = (1,062) + (599) - (270) - 161

BMR = 1,230

In this case, Ana Carolina's basal metabolic rate is 1,230 calories daily

As example: Calculating BMR for males:


  1. Height in centimeters - 170

  2. Weight in kilos - 80

  3. Age - 56 years

Applying the Basal Metabolic Rate equation:

BMR = (height in centimeters x 6.25) + (weight in kilograms x 9.99) - (age x 4.92) + 5

BMR = (170 x 6.25) + (80 kilos x 9.99) - (56 years x 4.92) + 5

BMR = (1,062) + (799) - (275) + 5

BMR = 1,591

In this case, Ricardo's basal metabolic rate is 1,591 daily calories

It’s not so difficult. You can calculate by hand or simply use an online basal metabolic rate (BMR) calculator.

So, if you apply your personal information in this equation you will have as result your basal metabolic rate (BMR) or the number of calories your body daily need to support your basic and vital functions.

Remember that the one above is based on the Mifflin St Jeor equation which is the most accurate equation right now. But you can find BMR calculators online that use different equations such as Harris-Benedict, or the Katch-McArdle equation. However, all these online services are gradually shifting to the above equation.

Another quick and easy way to calculate an estimative of males or females BMR is the following:

  1. What is your current weight in pounds?

  2. What is your ideal weight in pounds? (Your ideal weight is the weight that you feel really good and energetic)

  3. If your current weight is different from your ideal weight, use your ideal weighIf you want

  4. to keep your current weight, multiply your current weight in pounds by 12

  5. If you want to lose weight, multiply your ideal weight by 10

For example: Ana Carolina (she wants to keep her current weight)

  1. Current weight: 132 pounds

  2. Ideal weight: 132 pounds

  3. Goal: to keep her weight for the long run

BMR = 132 x 12 = 1,584 daily calories, or:

Another example: Claudia (wants to lose 11 pounds of her current weight)

  1. Current weight: 132 pounds

  2. Ideal weight: 121 pounds

  3. Goal: to lose 11 pounds

BMR = 121 x 10 = 1,210 daily calories

* As soon as Claudia reaches her ideal weight (losing 11 pounds), she should go back to this formula and multiply her current weight, 121 pounds, by 12. This is because when she reaches her ideal weight, she shouldn’t restrict anymore her caloric consumption.

Calculate your basal metabolic rate (BMR) and memorize this number. Then, remember that your BMR indicates an estimative of theminimum number of calories that support your vital functions on a daily basis. Also, it is important to understand that our body has a defense mechanism that is activated when we restrict our daily calories intake to less calories than our BMR.

Conventional nutritional understanding tells us that eating less calories than we need will help us lose extra weight. However, it is not always true. And by restricting too much our caloric intake may not help at all lose extra weight. In fact, our body has a protective way to counteract the restriction of calories by reducing our metabolism. And as a side effect it stores fat in our body to guarantee our survival. (4)

With that in mind, if you are always dieting and controlling everything you eat in order to keep your weight perhaps when you estimate your BMR you will discover that you are eating less calories than you should be eating, andby adding calories back to your diet will assist you lose weight, be energetic and avoid the symptoms listed at the beginning of this article that are frequently caused by restrictive diets.

Without any question, being overweight or obese puts us at risk for a multitude of health conditions. But it is also clear that keeping us lean and thin by restricting our nutritional needs has a high price in our health and well-being too.

So, let's talk about the second step to correct nutrient imbalances. Are the calories from our BMR enough to guarantee us energy and well-being?

This question and more are going to be answered in my next articles.

See you soon and please, leave your comments or questions below..

Be Healthy to Fully Enjoy Your Life.

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