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Managing Your
Body Weight with Mathematics
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When actress Renee Zellweger was asked how she gained the weight
for the role of Bridget Jones in the movie the “Bridget Jones’
Diary,” and lost it after the movie, she said, “It’s really just
maths.” In other words, if you eat more calories than you use,
in the long-term, it will translate to weight gain. Eat less
than you use, and you lose.
Exactly What is Metabolism -
Before we go into the maths, we need to know a little about
metabolism. Metabolism is just a big word to describe the
process in which the body uses the food we eat to produce
energy. As the end product of metabolism is energy, it is
logical that metabolism is also measured in the same unit as
energy – kilocalories, or Kcalories for short. Under the metric
system, energy is measured as kilojoules (kJ).
A person’s basal metabolic rate (BMR) is the number of calories
a person needs in a day to maintain vital body functions (e.g.
brain activity, heartbeat, breathing) when he or she is at rest.
Your BMR usually accounts for about half or more of the calories
you will need in a day. A person’s BMR usually does not change
much with his or her weight, but can be increased if the person
has a higher ratio of muscle to fat. This is one of the reasons
why men have higher metabolisms than women. In addition, most
people’s BMR decreases as they age, making it harder to control
their weight. Researchers think that the decline in metabolic
rate with age has more to do with the loss of muscle as we age,
rather than the aging process itself, and thus can be slowed
with strength-training exercise.
The level of physical activity also determines how many calories
are needed. Physical activity includes every kind of activity,
from playing basketball to sitting down watching television. Of
course, the more vigorous the activities, the more calories are
used.
Weight in the balance
Most dietitians agree that there is nothing complicated or
mysterious about weight loss and maintenance. It really is a
matter of balancing the number of calories coming in vs. the
number going out. What may be tricky is figuring out the number
of calories your body needs in a day, and how many calories
there are in your food.
There are many free calculators on the internet that help you
calculate the number of calories you need based on your weight,
age and your daily activities. Check out the Calorie Burner on
the AFIC website:
http://www.afic.org/Burner.htm
or on the Free Calorie
Counter on
http://www.caloriesperhour.com/
Not all foods are created equal
Once you have determined how many calories you need, then need
to determine how many calories are being consumed in your
typical daily diet, and then how to make the balance. |
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Different types of foods have a different number of calories for
the same amount of food. For example, 1 g of a carbohydrate or
protein has 4 calories while 1 g of fat has 9. This means that
if you eat the same amount of fat as carbohydrates, you are
actually eating more than twice as many calories. As most foods
consist of a combination of carbohydrates, protein and fat, most
of us would have to depend on some kind of labelling to tell us
how many calories a certain food contains.
For cooked and unpackaged food, check out the Nutrition Society
of Malaysia’s food database that has the nutritional information
for hundreds of Asian food items at
http://www.nutriweb.org.my/
For globally available foods, the
Nutrition Data website,
http://www.nutritiondata.com, offers a very extensive
database and easy-to-use calculator.
Beverages also add to our daily caloric intake. For instance, an
8 oz can of regular coke has 104 calories while a regular 12 oz
can of beer has 146 calories. A glass of milk tea may have about
100 calories but add flavoured syrups and whipped and the total
could be as many as 300-400 calories!
Every bit helps
So the mathematical equation is clear-cut: eat more than you use
and you put on weight, eat less and you lose. Bear in mind that
weight gain usually happens gradually over time and eating an
extra 100 calories a day could result in a 1 kg weight gain in a
year. Similarly, reducing 100 calories in your diet each day, or
using an additional 100 calories per day could help you to keep
your weight stable.
Eating 100 calories less or burning 100 calories doesn’t require
lot of effort – just look at the table of foods and activities
equal to 100 calories for ideas on achieving this.
Those seeking to lose weight would have to use more calories in
physical activity or eat fewer calories or both.
The World Health Organisation (WHO) recommends that people do at
least 30 minutes of moderate physical activity every day. These
need not necessary mean spending 30 minutes in the gym or
working up a sweat. In fact, many activities that we do during
the course of the day (e.g. housework, climbing the stairs,
walking, gardening) count towards the 30 minute goal.
However those seeking to lose weight may have to do more. The
WHO recommends at least 60 minutes of moderate to vigorous
physical activity every day as a weight control measure.
In conclusion, remember that maintaining a healthy weight is
primarily about keeping a balance of the number of calories
going in vs. the number of calories going out. Just do the maths!
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10 ways to eat 100 calories less
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10 ways to burn 100 calories
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