We
diet, we exercise, we struggle, we choose our foods wisely, we are very
conscious of our habits … and still we don’t lose all the weight we want to, or
even if we do, we gain it all back in a flash.
We start believing that we did something wrong, and we go at it again,
this time with a starvation, easy-fix diet, only to go down a few pounds and
then put it all back again, and again.
It reminds me of a comic strip I read some time ago in a newspaper,
which said: “I keep losing weight, but it
… keeps finding me!” It may sound
funny, but for those of us who have been down this path, it’s nothing but
amusing … it’s actually very frustrating.
Well,
today I decided to talk to you about the hidden “devil” in our bodies, who sometimes
has more control over our bodies than we do … It’s name is METABOLISM!
Metabolism
refers to the countless chemical processes going on continuously inside the
body that have the purpose of providing energy for the vital activities and
processes and allow life and normal functioning. These processes require energy
from food. The amount of calories your body burns, at any given time, is
regulated by your metabolism. Moreover, the body's metabolism, is governed by
hormones, which are chemical messages secreted by the glands of the endocrine
system and the nervous system, and it can be upset by a variety of
events, including genetic disorders and hormonal problems.
The
metabolic rate (or total energy expenditure) is the rate of energy production
and expenditure at a given moment, and it’s divided into three states:
· Basal metabolic rate (BMR)
- the amount of calories burned at rest and contributes 50 - 70 per cent of our
energy needs.
· Energy expenditure in physical work - the amount of calories burned during movement and
physical activity; it contributes at least 20 per cent of our energy needs and
it is also known as the “thermic effect of exercise”
· Energy expenditure associated with eating, digesting
and metabolising food - also known as the “thermic
effect of food”; it contributes about 5 - 10 per cent of our energy needs.
The first two
states are proportional to body weight. A person with a high body weight has a
relatively high BMR because of a larger amount of muscle required to carry the
larger body. This person will also have a higher rate of energy expenditure in
movement activities, such as walking and most physical work. The opposite is
true for a person of low weight.
Now, all is
“fine and dandy”, you may say … “enough with the scientific jargon” … you may
continue to say … and I don’t blame you … so here’s what it boils down to … the
factors affecting our BMR:
· Body size - larger
adult bodies have more metabolising tissue and a higher BMR.
· Age - metabolism
slows with age due to loss in muscle tissue, but also due to hormonal and
neurological changes. Beyond maturity there is a gradual fall in BMR per
kilogram (2.2 pounds) body weight of about 10 per cent per year.
· Growth - infants
and children have higher energy demand per unit of body weight due to the
energy demand for growth and the energy demand for maintenance of body
temperature.
· Gender - generally,
men have faster metabolisms than women because they tend to be bigger and have
less body fat – the battle of the sexes continues!
· Genetic predisposition
- the metabolic rate may be partly decided by a person's genes – blame it on
your parents!
· Amount of lean muscle tissue - muscle burns calories voraciously – “couch
potato-ing” is not an exercise!
· Amount of body fat
- fat cells are sluggish and hardly burn any calories at all; they need next to
no energy to maintain themselves.
· Hormonal and nervous controls - BMR is controlled by the nervous and hormonal
systems; hormonal imbalances can influence how quickly or slowly the body burns
calories.
· Dietary deficiencies
- for example, a diet low in iodine reduces thyroid function, which slows the
metabolism.
· Environmental temperature
- if the temperature is very low or very high, the body has to work harder to
maintain its normal body temperature, thus increasing the BMR – don’t blame me
if I move to Alaska and then to Equator!
· Infection or illness
- BMR increases because the body has to work harder to build new tissues and to
create an immune response.
· Crash dieting, starving or fasting - eating too few calories encourages the body to slow
the metabolism to conserve energy; BMR can drop by up to 15 per cent. Spontaneous
activity is also reduced, achieving a further 15 per cent reduction in energy
expenditure. These two combine to reduce energy usage and to conserve life.
There is also loss of lean muscle tissue, which further contributes to the drop
in BMR – remember this next time you go on a crash “magic” diet!
· Amount of physical activity - hard working muscles need plenty of energy to burn.
Regular exercise increases muscle mass and 'teaches' the body to burn calories
at a faster rate, even when at rest – flipping channels is not an exercise
either!
· Drugs - some drugs,
like caffeine or nicotine, can increase the BMR.
So remember:
The metabolic rate is
influenced by many factors, including age, gender, muscle-to-fat ratio, amount
of physical activity and hormone function; some of these you have control over
and may alter, but some you can’t, … so you are not always to blame! Therefore, when you actually decide on
liposuction, tummy-tuck or any other “weight decreasing” or “body contouring”
surgical procedure … you shouldn’t feel guilty!
