Restructure Your Body: Lose Fat, Build Muscle

o combat aging, we need to lose fat and build muscle because the aging process restructures the body.By age 20 or so most people stop growing upwards and start growing outwards, adding fat and losing muscle.

Sidebar: Christian Finn asks, "When you lose fat, will you lose muscle and bone too?"
Thanks to J. Harris and F. Benedict, we can predict how much fat a person will gain with the passing years. In 1919, Harris and Benedict developed formulas for estimating daily calorie needs based on gender, weight, height, and age. Their formulas state that people tend to burn fewer calories as they age: the base metabolic rate (BMR) for men declines by 6.8 calories per day per year; the BMR for women declines by 4.7 calories per day per year.

The table below illustrates what might happen to a married couple, a man and a woman over a span of 50 years, from age 20 to age 70.

Let's assume that the couple continues to consume a fixed number of calories every day over the whole 50-year period, just enough for a person age 20. As the man and woman age, they eat the same number of calories, but they burn fewer calories. They store the surplus fuel as fat. Clear physical changes will eventually show that they need to lose fat.
  • Each partner starts with a body mass index (BMI) of 22, which is normal.

  • At age 20, the man has about 15% body fat, while the woman has about 20% body fat.

  • Both partners become shorter by about 2% because their spinal discs shrink with age.

  • Both partners gain weight because their metabolic rates decline while their calorie intakes are constant. Continuing to eat the same amount as they did at 20 causes them to pack on fat. To lose fat, they might eat less, but there is a better way.

  • By age 70, both partners are overweight, not far short of clinical obesity, defined as BMI greater than 30. The man has gained 39 pounds weight, and the woman 28 pounds.

  • Both partners are now concerned to lose fat.

  • Because both partners have suffered age-related muscle and bone loss (sarcopenia and osteopenia), fat gain is far in excess of weight gain. Thus by age 70, the body fat of both partners reaches almost half of total weight without eating or drinking any more than they did at age 20. To lose fat by diet alone would risk losing muscle and bone too.

Age and Weight Gain
Effect of Aging on Weight Gain
(BMR = Base Metabolic Rate; BMI = Body Mass Index)

To obtain a copy of the mathematical model, please contact me by e-mail.

What's Missing in this Model?

This model of fat gain has something missing: a mechanism for the slow fall in metabolic rate with age, less than 1/2 of one per cent per year. We ask ourselves, "What other process occurs at this slow rate that could cause a decline in metabolic rate?" The answer is speculative, but plausible: sarcopenia, age-related muscle loss. Because muscle is more metabolically active than fat, loss of muscle with age could explain why we burn less fuel as we age. Fat requires less energy to maintain than muscle. If we could keep or restore muscle mass, then it should be possible to maintain a higher metabolic rate and thus avoid gaining fat as we age. Weight training appears to be essential for both men and women rather than an option for men only.

But I Don't Want Big Muscles, I Only Want to Lose Fat

The muscle magazines have done a great disservice to the public by creating a bias against muscle building, especially among women. Their advertisers, the supplement companies, have promoted the idea that anybody can build muscle in no time at all. Muscle magazines print pictures to prove it. What they don't tell you is that the bodybuilders in the advertisements (both men and women) have endangered their health by using illegal drugs.

Natural bodybuilders use no such drugs, though most use protein supplements either for convenience or to avoid the saturated fats in meat. Supplementing with protein also helps to lose fat because people who eat more protein tend to eat fewer calories.

Yes it's possible to build muscle the old-fashioned way, using only natural methods. But it takes years, not months. The amount of muscle gained depends on sex, age, and body type. Someone who begins buiding muscle at age 40 will do well to regain the 5% to 10% of muscle already lost through the aging process. To regain muscle after age 40 is still possible, but very much more difficult because by age 50, 10% to 15% of muscle has been lost. After age 60, muscle loss may accelerate, so that by age 70, over 25% of muscle may have been lost. Over the age of 75, about 30% of men do not have the strength to lift a 10-pound (5 kg) weight over their heads.

Building muscle may be the best way to keep the metabolic furnace going. If so, then building muscle may be the best way to make sure that once we lose fat, we keep it off.

To maintain the same weight at age 70 as at age 20, a person should:

  • Maintain muscle mass by weight training from age 20.


  • Gradually reduce calories by about 1/2 of one percent per year. By age 70, a typical man would be eating 350 fewer calories per day, a typical woman about 250 fewer calories per day.


  • Exercise moderately, increasing the number of hours per week from two hours at age 20 to ten hours at age 70.


  • Combine calorie restriction with moderate exercise, including both aerobics and weight training.


  • determine to lose fat already gained by moderate calorie restriction and exercise, both aerobics and weight training.

The Shocking Truth

What I find most shocking: The gradual storage of excess fat is considered part of the "normal" aging process. If you are "normal", this process is happening to you, or has already happened to you, as it happened to me. By July 2003 at the age of 72, I reached a BMI of 28 and 40% body fat.

If this is "normal", then heart disease, arthritis, diabetes and all the chronic diseases associated with this process are also normal. I told myself, "If this is normal, let me be abnormal!"

It's Never Too Late!

"It's normal for your age." I used to believe that. But not anymore. And you shouldn't believe it either. Becoming overweight, losing muscle and bone, developing chronic diseases are the "default options", what you get if you take no action. I chose to defy aging: to lose fat and build muscle.

During the 12 months from July 2003 until August 2004, by walking a few hours per week, I lost 11 pounds (5 kg). In August 2004 at the age of 73, my doctor shocked me into action by showing me that I was well on my way to serious heart problems. I stepped up my exercise program and reformed my eating habits. By January 2006, I had lost 34 pounds, reduced my BMI to 21.5 with body fat to 21% and an estimated 5 pounds (2.3 kg) gain in lean body mass (muscle and bone).

My goal for 2006 is reduce body fat to 15% and to increase lean body mass (muscle and bone) by at least 2.5 pounds. These are realistic minimum goals, but not limits that I place on progress.

Lose Fat and Build Muscle
A Practical Guide

You can find hundreds of trainers on the internet. Most of these trainers seem to me to be sincere and well qualified. Yet the advice they provide seems more suited to younger trainees than to middle-aged adults.

Little advice is provided on health and safety aspects important for older adults. Many trainers are professional athletes who engage in competitive sports and body-building competitions. Thus, much of the advice provided is inappropriate for people whose main interest is health and fitness, with improved appearance a welcome side-effect rather than the main goal, as it is for body-builders.

I spend a lot of time studying what professional trainers and athletes say about physical fitness, fat loss, sports training and body-building. I do this so to filter out ideas that may be less important for older adults and to identify ideas that apply to both younger and older adults. What's more, I look for ways of adapting training methods to the special needs of those older adults who may have difficulty with specific training methods and exercises.

The following links present practical tips and guidelines for losing fat and gaining muscle at any age, with special emphasis on training for people who have reached middle age.

How to Lose Fat and Build Muscle At Any Age

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