Ever feel like your body is speaking in code? Well, it kind of is! Today, we're going to crack that code and learn how understanding three key metrics - BMI, BFP, and BMR - can help you achieve a leaner body and lower blood pressure.
Spoiler: The abbreviations above are linked to body fat and as we all know too much of it can be problematic. In fact, high levels of body fat, or obesity, raises your risk of developing many of the common chronic health conditions including high blood pressure. Let’s dive in.
BMI: The "Basic Measurement Indicator" (Not Really, But It's Catchy!)
Let's start with BMI, or Body Mass Index. It's like your body's quick elevator pitch - short, simple, but not telling the whole story.
What it is: A basic calculation that divides your weight by the square of your height.
What it tells you: Whether you're underweight, normal weight, overweight, or obese.
The plot twist: It doesn't distinguish between muscle and fat. So if you're powerfully built, your BMI might say you're obese.
BFP: The "Body Fat Percentage" (No Clever Acronym Here, Folks)
Next up is BFP, which gives us a more detailed look at what's really going on under the hood.
What it is: The percentage of your total body weight that's composed of fat.
What it tells you: How much of you is really... well, you, and how much is your fat suit.
Why it matters: Too much fat can lead to health issues, but too little can cause problems too. It's like Goldilocks - you want it just right!
BMR: The "Burn More Regularly" Rate (Okay, I Made That Up)
Finally, we have BMR, or Basal Metabolic Rate. Think of it as your body's idle speed.
What it is: The number of calories you burn just by existing. Yes, breathing and thinking burn calories!
What it tells you: How many calories you need to maintain your weight if you did nothing but binge-watch Netflix all day.
Why it's cool: It's the key to understanding how much you can eat without gaining weight (if you are not moving or exercising). It's like a cheat code for your diet!
How to Calculate Body Fat Percentage
Several methods can be used though some are more accurate than others.
DEXA, or dual-energy X-ray absorptiometry, scans capture images of the whole body, measuring the absorption of X-ray photons in order to determine a person’s body fat percentage. DEXA scans are accurate and more readily available than other tests. They usually cost upwards of 150 US dollars per test.
Calipers can be used to gather skinfold measurements, also referred to as a “pinch test.” Measurements are taken at 3 to 10 points on the body with the calipers, and the measurements are then plugged into a formula. It’s a good way of measuring your body fat percentage as long as human error is at a minimum.
Bioelectrical impedance scales that measure body fat are widely available, but they’re less accurate than DEXA scans. Factors like sodium and water content can impact the accuracy of measurements. Generally, these scales are most useful for identifying trends as long as you weigh yourself at the same time each day.
What Is Considered a Healthy Body Fat Percentage?
Body fat percentage also reflects how physically active and fit you are. For instance, if you’re a professional athlete, you likely exercise more often and more rigorously, so your body fat percentage is going to be lower than average. With that said, normal body fat percentage ranges that are generally considered healthy for both men and women are provided in the chart below.
Healthy Body Fat Percentage for Men and Women | ||
Age | Body Fat Percentage for Men | Body Fat Percentage for Women |
20-39 | 8%-19% | 21%-32% |
40-59 | 11%-21% | 23%-33% |
60-79 | 13%-24% | 24%-35% |
Source: American Journal of Clinical Nutrition |
Why Does Body Fat Percentage Matter?
Body fat percentage is an indicator of physical fitness, and keeping it in a healthy range is important. The higher somebody’s body fat percentage, the more likely they are to develop heart disease, high blood pressure, type 2 diabetes, breathing problems like sleep apnea. It may lead to higher cholesterol, which can lead to heart disease.
How to Lower Body Fat Percentage
Lowering your body fat percentage will likely involve reducing the number of calories you eat along with increasing your physical activity level.
There are many ways to combine changes in your eating habits with elevated levels of physical activity to support body fat reduction. Studies show that 30 minutes of aerobic exercise a day correlates with sustained weight loss. Aerobic exercise can take many forms including walking, running, swimming and/or cycling, and should be based on your level of physical fitness.
In addition to reducing calories and increasing exercise, relatively new evidence suggests that weight training also has a positive impact on body fat percentage. A large 2022 systematic review of 54 studies in Sports Medicine concluded that resistance training effectively reduces body fat, including fat around the abdominal organs.
Body Fat Percentage (BFP) vs. Body Mass Index (BMI)
BMI, or body mass index, is a basic calculation achieved by dividing a person’s weight in kilograms by the square of their height in meters. Basically, BMI is a very rough weight evaluation.
A quick and easy calculation, BMI essentially categorizes people as underweight, normal weight, overweight and obese. It doesn’t give the full picture of your metabolic health, and it’s not the most accurate for classifying your health status because it doesn’t take into account how much of your total body weight is actually muscle. That is why body fat percentage is always a better indicator.
When to See Your Doctor
Your BMI can be a quick way to assess your risk for metabolic disease, as well as learn your weight classification. If you find yourself with a high BMI or out of range, it might be best to also test your body fat percentage.
Consider body fat testing if you notice unexplained weight gain of at least 10 pounds over the course of six months and everyone should get an annual physical to assess their general health.
Will You Lose Weight if You Eat Your BMR?
Short answer: yes, but it’s not sustainable.
Remember, your BMR is just the number of calories your body burns at rest and does not account for the calories you need to walk, talk, exercise, etc. When thinking about your caloric needs for a meal plan, you must account for your current activity level or your increased activity level if you plan to exercise more. To do that, convert your BMR to your Total Daily Energy Expenditure (TDEE).
How to calculate your Total Daily Energy Expenditure (TDEE) from BMR
To calculate your TDEE, multiply your BMR by a factor that represents your estimated energy level. Those conversions are:
Sedentary, little or no exercise, TDEE = 1.2 x BMR
Lightly active: light exercise 1-3 days/week, TDEE = 1.375 x BMR
Moderately active: moderate exercise 3-5 days/week, TDEE = 1.55 x BMR
Very active: heavy exercises 6-7 days/week, TDEE = 1.725 x BMR
Extremely active: Very heavy exercises 2 times/day, TDEE 1.9 x BMR
When trying to improve your body composition and body fat percentage, you must reduce fat mass and gain muscle. That’s why it takes a conscious effort to change your body composition.
IMPORTANT: this also means that your diet must also match what your current goal is—body fat loss and/or gaining lean body mass. People who don’t calibrate their diet to match their goals end up sabotaging themselves by setting fitness and meal plans that are at odds with each other.
The most classic example is this: “I want to get lean, so I am going to diet (eat fewer calories) and work out more (increase energy expended).”
This isn’t a bad plan—if you’re only looking to lose fat. If you’re looking to build muscle and get stronger, it’s very unlikely that you will reach your goal because you will lose muscle.
If your goal is to build lean body mass, you must exceed your daily caloric needs and combine it
with strength training.
What foods should you eat for muscle gain?
Research suggests that to maximize lean mass gain while minimizing fat gain, the increase in calories should comprise both protein-rich foods and carbohydrates.
However, a word of caution about protein—before you increase your diet with nothing but protein, consider this: there is a point where eating more protein won’t lead to a measurable increase in lean mass. In a 2006 study of collegiate level athletes, no benefit in muscle or strength gain came from protein consumption that exceeded 0.9 g of protein per pound of body weight.
What is the practical way to track progress with Body Fat Percentage?
As we explained earlier the most precise way to measure BFP is with DEXA scan. However if you want to check BFP often and track your progress the more practical way to do it is with bioelectrical impedance scales.
There are many devices on the market which cost below $100 and choosing between them is a matter of personal preference. After a one off payment you can do measurements at home as often as you want and see the trends immediately. I use DARA scales from FitTrack primarily because I find their app very convenient. I can easily see my progress with body fat and muscle metrics after every morning measurement and adjust my diet and training accordingly.
Final Takeaways: BMI, BFR, Body Composition and BMR
BFR provides a more detailed picture of your metabolic health than BMI.
Since your BMR is closely linked to your lean body mass, any changes will affect the number of calories you burn.
If you want to gain lean body mass, you will need to do strength training and your energy needs are going to increase. You will need more calories to continue to fuel that growth and these calories should come primarily from extra protein consumption.