“Physical Fitness” means being well rounded and competent in all areas of fitness. Fitness isn’t just the absence of disease, but also a general ability to move confidently in a variety of activities. The professional health circles consider fitness to be a combination of Strength, Cardiovascular health, Mobility, and Healthy Body Composition. One isn’t more important than the other, and each contribute in their own way to preventing various diseases and allowing you to thrive physically.

A healthy body composition means having an appropriate amount of body fat, lean muscle mass, and bone health. Body composition affects all other aspects of physical fitness. While the affects may be subtle, they can make a huge difference in your longevity and quality of life.

Excessive body fat (above about 25% for men and 30% for women) has been strongly linked to cardiovascular disease, diabetes, and stroke. Excessive fat is distributed around the abdomen (android fat) and around the hips (gynoid fat). Excessive android fat in relation to gynoid fat (called the android/gynoid ratio) is also linked with increased risk of cardiovascular disease, diabetes, etc.  For example, if you have two males at 30% body fat, but one has 60% of that bodyfat above the waist, and the other has 40% above the waist and 60% below the waist, then the person with 60% android (above the waist) fat is MORE at risk for the above diseases.

Mechanically, excessive body fat puts undue stress on the joints which speeds up degradation. This may be felt after a long day of being active, or after years of low-level wear. The act of carrying extra weight also makes the relative feeling of exertion greater. Activities that should not be taxing, such as walking up a flight of stairs, may be more difficult with increased body fat.

One common misconception with increased body fat is that because the person is used to carrying more weight, they are going to have more muscle under the fat. But muscle requires significant and progressive stress to stimulate growth. If you slowly gain body fat over the course of a decade, the acute stress on your muscles isn’t enough to cause adaptation. Your muscle mass ends up staying about the same, but has to carry a heavier load.

Being severely underweight, or losing weight too fast, can affect your bone density and set you up for developing osteoporosis or osteopenia. This is why professionals suggest losing around 1 to 2 lbs per week. Rapid weight loss above this rate can result in the loss of three times more lean tissue than fat tissue! Similarly, if you try to lose weight strictly through dieting, or dieting and cardiovascular exercise, much of your weight loss will be from muscle and bone mass. On the other hand, if you are engaging in heavy resistance training and impact exercise while you also diet, much of your muscle and bone mass will be maintained. Strength training essentially tells your body “hey! We need these muscles to lift heavy stuff! Let’s not break them down for fuel.”

This can explain why some people hit a plateau when they diet: Muscle is metabolically active and contributes to daily caloric burn. If you decrease muscle mass, then your body’s metabolism will also decrease. A good goal for fat loss is to maintain as much muscle mass as possible, which keeps your metabolism stoked.

We are constantly told to lose weight, diet, and exercise. But rarely is it spelled out for us why or how it helps. While it may seem like a poor body composition isn’t making a big difference, it is constantly affecting your overall fitness and quality of life. Use this knowledge to dial in your goals, gain motivation, and reach the best version of you possible!