Principles of Weight Control – Part Three

Weight Gain and Weight Loss

The important point to realize about weight gain is that it occurs gradually.  It is physiologically impossible for someone to put on 2 (let alone 20) pounds of fat over night.  It takes months and years of “slightly too much food” and “not quite enough physical exercise” for the weight gain to occur.  Therefore you should realize that losing the weight (fat) can’t happen overnight either.  The only healthy way for your body to lose weight is gradually, no more than 1 kilogram (2.2 lbs) per week.  If you lose  more than one kilogram per week, it will be easier for you to gain the weight back later.  In addition, any excess weight that is lost (greater than one kilogram per week) will likely be lean tissue/muscle, which is not the type of weight you want to lose.

The body mass of most adults fluctuates only slightly during the year, even though a normal person’s annual food intake averages close to 900kg (1980 lbs.)  This fact is impressive considering that a slight but consistent increase in food intake can cause body mass to increase substantially if there is no accompanying increase in daily energy expenditure.  For example, if a person who originally weighed 75 kilograms ate only an extra 100 calories per day for 10 years (with no increase in energy expenditure through exercise), he or she would gain 47 kilograms, or 105 pounds in that decade (since each pound of body fat contains about 3500 calories).  On the other hand, if daily caloric intake was reduced by 100 calories per day by walking or jogging one mile every day, then the caloric deficit would be equivalent to a reduction of about 9.5 kilograms or 21 pounds of fat in one year.

Metabolic Rate

Unfortunately, though, it is not always this easy. First, a person’s metabolic rate can influence the  efficiency with which they store calories.  Metabolic rate in influenced by a number of factors, including genetics, hormone levels, climate or temperature, stress level, presence of disease or illness, and the proportion of adipose (fat) to muscle tissue.  Muscle is much more metabolically active than fat, which means that even when a person is resting, muscle tissue is burning more calories that fat (adipose)  tissue.

Thus, part of the reason people who are lean and have more muscle are able to eat more and stay slim is because their muscle burns off the extra calories they eat before the calories can be stored as fat.

It is clear that weight training is the best way to increase muscle mass, which makes it an effective means of increasing your metabolism to burn extra calories all day long.  Each additional kilogram of muscle tissue can raise your metabolic rate by approximately 100 calories per day.  Thus, an increase in muscle mass of 2 kilograms through weight training will result in an increase in metabolic rate of about 200 calories per day, which is equivalent to 73000 calories per year, or 9.5 kilograms of fat!