What Is Body Composition?

You could be normal weight but have a body composition that is overfat (think of those pudgy but thin actresses from the 1920s – a Mary Pickford type). Scientists refer to this body type as TOFI (thin on the outside, fat on the inside). It’s unhealthy. So optimally, don’t focus on the bathroom scale. Focus first on achieving a good body composition.

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Body Composition: Fat on the Inside

What Is Body Composition? | Facts About Fat

For a good body composition, what’s especially critical is ratcheting down the amount of fat we’re carrying around, particularly belly fat.

Losing body fat – and certainly, gaining lean muscle mass – means we’re not only looking better, we’re improving our overall health.

Benefits of a Good Body Composition

Having a good body composition has many benefits, including:

  • Decreased risk of type 2 diabetes, hypertension, and heart disease
  • Increased functional ability, allowing us to move and exercise more freely, which allows us to burn more calories
  • A better calorie-burning metabolism throughout the day
  • A lean and toned body
  • Better success at losing weight permanently

Gaining Health | Fast Results

The good news: You don’t have to wait till body fat drops dramatically (which often takes months) to see dramatic improvements within.

During their two- to three-week health retreat at the Pritikin Longevity Center, guests will start to lose body fat and gain muscle mass, and that’s wonderful. But what’s especially rewarding are the health results achieved in this short amount of time.

Body Composition Scan at the Pritikin Centeråç
Guests at the Pritikin Center are often amazed at how quickly their bodies begin to transform from the inside out. As these “before” and “after” DEXA scans reveal, at Pritikin you’re improving your body composition by gaining muscle and eliminating fat. Dieting away muscle can slow your metabolism, making it impossible to maintain a healthy weight.

Within two to three weeks of eating and exercising Pritikin-style, blood sugar decreases markedly, research1 has found. So does blood pressure2 and cholesterol.3 What’s more, the diagnosis of the pre-diabetes condition, metabolic syndrome, is often reversed4.

“Bottom line: Losing body fat happens slowly, but getting healthy can happen very, very quickly, especially with a program like Pritikin,” sums up Danine Fruge, MD, Medical Director at the Pritikin Longevity Center.

Essential Body Fat

Healthy body function requires a certain amount of essential body fat. This fat is vital for temperature regulation, shock absorption, and other functions. Average essential fat for women is 12% of body weight; for men, it’s 3% of body weight.

Nonessential Body Fat

Some nonessential body fat, also termed storage fat, is also required for good health, particularly for protection of internal organs in the abdomen and chest.

The following graph divides body fat percentages into various categories. A healthy goal is reaching the “Average” range; even better, the “Fit” or “Athletic” ranges.

Different Levels of Percent Body Fat

Women Men
Athletes 14 – 20% 6 – 13%
Fitness 21 – 24% 14 – 17%
Average 25 – 32% 18 – 24%
Obese 33% or higher 25% or higher

How To Improve Body Composition | #1
Resistance and Cardiovascular Exercise

Resistance exercise preserves and builds lean muscle mass, and burns calories. Types of equipment and/or classes for resistance training include:

  • Machine weights
  • Free weights
  • Resistance bands


  • Aquatics
  • Yoga
  • Calisthenics

Cardiovascular exercise puts lean muscle to work to burn calories.
There are all kinds of cardiovascular exercise, also known as aerobic exercise, including:

  • Walking
  • Running
  • Cycling


  • Swimming/Aquatics
  • Rowing
  • Dancing


  • Cross-country skiing
  • Tennis/racquetball
  • Basketball


Always keep in mind that when you cardio-exercise at higher intensities, for example, the interval training that people learn at the Pritikin Longevity Center, the rewards are more calories burned during exercise, plus more calories burned after exercise.

“But it’s not every day that we should be working out at higher aerobic intensity, just alternating days, for example, Monday, Wednesday, and Friday,” clarifies Ivan Ferran, Director of Clinical Exercise at Pritikin.

Three days a week is doable for most of us, and well worth it. These higher intensity workouts are extraordinarily beneficial in helping us become leaner and fitter.

Before beginning a new exercise regimen like interval training, “be sure to undergo a complete physical evaluation and exercise tolerance testing, as our guests at the Pritikin health resort do,” recommends exercise physiologist Ivan Ferran.

How To Improve Body Composition | #2
Healthy Eating – The Pritikin Eating Plan

Exercise alone – without changes in caloric intake – may decrease fat and increase muscle. But for best results, choose the right foods, like the low-calorie-dense foods that make up the Pritikin Eating Plan, in addition to exercise.

With the Pritikin Eating Plan, you’ll be filling up on healthy, satisfying foods. They not only keep hunger at bay, they cut calorie intake. It feels good to know that you can eat well and lose weight.

What About the Body Mass Index (BMI)?

For years, scientists have tracked people’s weight using BMI, which is a measure of body fat based on height and weight. It has value, but there are times when it is woefully wrong.

For example, a lean, well-muscled man may have a slightly elevated BMI (because muscle weighs more than fat) but a perfectly healthy body composition.

Conversely, one could have a normal BMI but a body composition that is overfat (think of those pudgy but thin actresses from the 1920s – a Mary Pickford type). Scientists refer to this body type as TOFI (thin on the outside, fat on the inside).

Optimally, focus first and foremost on achieving a good body composition.

Track Your Body Composition at Home
Bio-impedance scales assess body composition as well as weight. With some, like the Withings scale above, you can even sync all your information to your phone or computer to track your progress.

How To Track Your Body Composition

Several years ago, the only methods available for measuring body composition were either error-ridden (skinfold calipers) or inconvenient (underwater weighing).

Significantly improved body composition testing is now available with duel energy X-ray absorptiometry (DEXA). DEXA testing is performed at Pritikin. It is quick and highly accurate, and X-ray exposure is very low.

Not as accurate but certainly a good choice for home use are scales, generally known as bio-impedance scales, like the one pictured below. Bio-impedance scales assess body composition as well as weight. With some, you can even sync all your information to your phone or computer to track your progress. You can buy bio-impedance scales just about anywhere, from Walmart to Amazon.

What Is Body Composition? | Summing Up

When physicians and other health professionals talk about body composition, they are generally describing the percentage of your body mass that is fat, and the percentage that is muscle.

Losing body fat and gaining muscle mass is incredibly important. The more lean muscle mass you have, the leaner, fitter, and healthier you’ll be.

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