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Understanding BMR and BMI - What is the Difference and How to Use the Information?

As part of my new book I want to help you understand your body. One of the keys to understanding your body is being able to calculate your metabolism and measure your body mass.

BMR stands for basal metabolic rate, this is the number of calories needed at rest to maintain your current weight. Your body needs these calories to accomplish its most basic functions to sustain life. These functions include breathing, circulation, nutrient processing, and cell production.

One great way to avoid fad diet products and to lose weight on your own in a sustainable way is to calculate your BMR and know your status. Then, by eating 500-1,000 fewer calories a day, you can lose 1-2 pounds a week.

The Harris-Benedict formula for calculating BMR:

  • For Women: 655 + (9.6 x weight in kilograms) + (1.85 x height in centimeters) – (4.7 x age in years).

  • For men, the calculation is: 66 + (13.7 x weight in kilograms) + (5 x height in centimeters) – (6.8 x age in years)

The next factor to take into consideration is your activity level. If you are:

  • Sedentary: Minimal (or no exercise), multiply your BMR by 1.2.

  • Lightly active: Exercise lightly (3 days a week), multiply your BMR by 1.375

  • Moderate active: Exercise (3-5 times a week), multiply your BMR by 1.55

  • Very active: Hard exercise (6-7 times a week), multiply your BMR by 1.725

  • Extra active: Very hard exercise (6-7 days a week), or have a physical job, multiply your BMR by 1.9

As an example, a woman that is 155 pounds and 5 feet 5 inches tall 655 + (9.6 x 70.3) + (1.85 x 165.1) – 4.7 x 42) would equal 655 + 674.88 + 305.43 - 197.4 = 1,437.91. Then consider that she may exercise lightly each week 1,437.91 x 1.375 = 1977.13.

This means she can consume 1,977 calories each day to maintain her current weight.

Basal essentially means base so this is the base amount of calories your body needs to function each day. To lose weight and still function at a good level though we also need to factor in our body mass index.

Your body mass index BMI which is the amount of fat on one’s body. This is based on an adult’s weight and height. The higher the BMI, the greater the risk of developing diabetes, high blood pressure, heart disease, and early death. To calculate it take your weight in kilograms and divide it by your height in meters squared. Or you can calculate it using your weight in pounds times 703, divided by your height in inches squared.

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BMI does have limitations it doesn’t consider people that may be a below-average height but above-average muscle mass. A body builder could be in this category. The other limitation for BMI is that it doesn’t account for age or gender. An older woman that is sedentary with a low muscle mass may have a normal BMI but be visibly overweight.

Here is a calculator that you can use online.

The standard classification of BMI is as follows:

  • Below 18-19 = underweight

  • 19-25 = healthy weight (low health risk)

  • 25-30 = overweight (moderate health risk)

  • 30-40 = obese (high health risk)

  • Over 40 = morbid obesity (very high health risk)

Using our woman from above the calculation would be 155 x 703 = 108,965 divided by 65 x 2 = 4,225 would give you 25.79. The person would fall just into the overweight category.

The higher your BMI is the higher your amount of fat. This increases your risks for diseases such as diabetes type 2.

It is important to understand the connection between these two calculations. If you have more muscle mass, you tend to burn more calories at rest. Muscle tissue requires more calories to maintain than fat tissue. Knowing these numbers can help you work with a nutritionist and medical professional to make determinations that will help you find your ideal weight.

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The last factor that I like to consider is an estimated daily protein needed to maintain current weight. For example, (sedentary) women need 46 grams of protein per day, while (sedentary) men require 56 grams of protein per day. You can also multiply 0.36 by your weight in pounds to achieve the amount of protein needed. If you have kidney disease or engage in minimal physical activity, the amount of need decreases.

The standard for caloric intake for women is 1,800 – 2,400 calories, (does not apply to pregnant and breastfeeding women) and for men is 2,400 – 3,200 calories.

Utilizing these numbers and understanding our food can help us make wiser food choices to achieve our ideal weight.

When you are choosing foods consider ones that are low in calories such as watermelon, blueberries, or avocados. Or foods that will promote weight loss such as almonds, fermented foods, or chickpeas.

A favorite thing for me to do is juice some great low-calorie fruits and vegetables and enjoy it for 7-14 days.

Weight loss juice recipe: lemon, lime, grapefruit, orange, cherry, pineapple, papaya, apple, raspberries, strawberries, carrot, cucumber, beet, cabbage, lettuce, celery, kale, 1 knob of ginger.

All the fruits can be peeled lightly. It is best if you juice for one use.

For a single juice one big piece of the larger fruits and vegetables and a small bowl of the small ones.

If you don’t have time to do this each day make a larger batch for a few days, no more than 3 and store in a glass container. If they are not in season frozen items are okay. This juice is delicious and filling. It is a great way to start reducing the number of calories you consume each day.

As you work towards achieving your ideal weight keep in mind the suggested caloric intake for weight loss is:

  • Women: Non-active = 1,000 – 1,200 calories, Active = 1,200 – 1,500 calories

  • Men: Non-active = 1,200 – 1,500 calories, Active = 1,500 – 1,800 calories

  • Teenagers: 1,200 – 1,800 calories

This amount will allow for 1-2 pounds of weight loss a week.

As you start achieving your ideal weight remember to check you BMR and BMI to ensure you are consuming the right amounts of calories each day.

Join our 21-Day Program - Path to Achieving Your Ideal Life and learn how to create positive daily habits to help on your weight loss success. Join here!


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