Published on January 28th, 2013 | by George Conte0
How to calculate Basal and Resting Metabolic Rate for weight loss and muscle growth
People interested in starting a diet to lose fat or an exercise program to gain muscle usually ask me about the same questions when they start. One of the first things they need to figure out right from the start is how many calories their body needs to burn to sustain itself (metabolism). This is a necessity for everyone to know before starting any nutrition plan because he must be able to calculate the ratios and quantities of macronutrient calories required in their diet, to achieve the desired, each time goal.
This article refers to healthy people who do not take any medication or have no medical restrictions on foods or quantities. In any such case, you should first consult your doctor, and his instructions and then create your personal diet plan.
I need to emphasize that the methods that will be discussed below, are not absolute, nor accurate, but are used as a starting point. Towards their goal, everyone should make the appropriate changes in diet, depending on his body.
The purpose of a nutritional plan is to help and to guide our body to achieve a particular result. This means we should provide a continuous flow of adequate amounts of nutrients throughout the day. A good way is by frequent and small meals. On a daily basis, five meals (three medium sized ones and two snacks).
First we need to calculate the calories that our body uses or the Basal Metabolic Rate (BMR). This is done by various equations. Here we cite the most known and widely used. You can use any of the three methods mentioned here. Remember that these methods are not accurate. The only way to accurately calculate BMR is by advanced and expensive technology like DEXA. These equations are the second best method and they are used as the foundation that you can later improve.
Basal Metabolic Rate (BMR)
Equation 1: Harris-Benedict:
|Men: BMR = 66 + (13.7x Weight (kg)) + (5 x Height (cm)) – (6.8 x Age (years))Women: BMR = 655,1 + (9.6x Weight (kg)) + (1.8xHeight (cm)) – (4.7x Age (years))|
Equation 2: Mifflin-St Jeor:
|Men: BMR = [9.99 x Weight (kg)] + [6.25 x Height (cm)] – [4.92 x Age (years)] + 5Women: BMR = [9.99 x Weight (kg)] + [6.25 x Height (cm)] – [4.92 x Age (years)] -161|
Equation 3: Katch-McArdle
This equation calculates the basal metabolic rate (BMR), based on the percentage of body fat.
|BMR = 370 + (21.6 x lean body mass in kg)|
All these equations, give similar results (but not the same exactly) for people with normal levels of fat. The Katch-McArdle equation is the most accurate but it’s hard to calculate the lean body mass if you don’t have access to advanced equipment.
Total energy expenditure (TEE)
Then, we need to find the Total energy expenditure (TEE). We can find the TEE if we multiply the BMR by a factor of our physical activity level (PAL) from the table below , depending on our daily activities.
Depending on the desired goal, we will change this number as follows:
For muscle growth, increase the calories:
- Increase in body weight by 1 kg / month -> increase calories by 250 calories / day.
- Increase in body weight by 2 kg / month -> increase calories by 500 calories / day.
- Increase in body weight by 3 kg / month -> increase calories by 750 calories / day.
Respectively, for weight loss, reduce calories:
- Reduce body weight by 1 kg / month -> reduce calories by 250 calories / day.
- Reduce body weight by 2 kg / month -> reduce calories by 500 calories / day.
- Reduce body weight by 3 kg / month -> reduce calories by 750 calories / day.
The proposed growth or weight loss is 2-4 kg per month. For muscle gain is about 1kg per month for starters and after a year it gets harder.
Once we calculate the total amount of calories that will lead us to our goal, we proceed to the distribution among the three macronutrient elements: proteins, carbohydrates and fats.
Here we should mention that 1g. protein and one gram of carbohydrate equals 4 calories, while 1 g. of Fat equals 9 calories.
That means for a hypothetical diet of about 1500 calories per day (random numbers), where someone takes 100 grams of proteins, 150gr carbohydrates and 50 gr fat, total calories will be calculated as follows:
100g. Proteins x 4 calories + 150g. Carbohydrates x 4 calories + 50g. Fat x 9 calories = 1450 calories.
Regarding the distribution of macronutrients, depending on the desired effect, the selected ratios are:
In case we want to increase muscle mass, usually a good selected ratio is 30/50/20, which means that 30% of the calories are from proteins, 50% from carbohydrates, and the remaining 20% from fat.
For bodybuilding we need grams of Protein around two times our body weight in kg. So a 70kg person needs about 70 X 2 = 140g of protein
In the above hypothetical example of 1450 calories, we calculate as follows:
- For proteins: 1450 x 30% = 435 calories from protein. 435/4 = 109 g. protein.
- For carbohydrates, respectively, 1450 x 50% = 725 calories from carbohydrates. 725/4 = 181 g. carbohydrates.
- For fat force: 1450 x20% = 290 calories from fat. 290/9 = 32 g. fat.
In this random example you can see that the protein is low because the total calories are low. Usually someone weighing 70kg that wants to add muscle will have a BMR of over 2000 calories per day.
In the case of weight loss, because we need allot fewer calories the selected two ratios are either 40-50/30/20 or 40-50/20/30 in the order listed always, protein / carbohydrate / fat. Protein is always better for weigh loss because it has lees calories than fat and also decreases the feeling of hunger.
In maintenance, use respectively, the ratio of 40/40/20.
Now that you understand BMR, TEE and how to calculate the amount of macronutrients you need for specific goals it is very easy to set your own target either that is weight loss or muscle growth and achieve it. Remember that once you have the knowledge it is very easy to take action and be successful at whatever you want to do. I hope this article helped you and I wish you good luck at whatever goal you have!