| 1. |
What are calories and
kilojoules? |
| |
Calories and kilojoules define the energy
value of food. Depending on the country we live in,
the nutrition data will be provided in calories [kcal]
or kilojoules [kj]. Calories are the amount of chemical
energy released as heat when food
is metabolized. A killojoule is a unit of electrical
energy used in physical sciences equal to the work done
when a current of one ampere is passed through a resistance
of one ohm for one second.
1 calorie = 4.2 kilojoules
So, if a portion of food contains 100 calories, multiply
it with 4.2 kilojoules to work out how many kilojoules
it has. It totals to 420-kilojoules.The balance between
our energy intake and the total calories burned denote
the level of weight gain or weight loss. Too many kilojoules
taken means too much body fat on you and fewer kilojoules
eaten indicate lesser fat accumulated. Though we use
large numbers when working with metric kilojoules, it
does not mean that kilojoules contain more energy. It
is only a different system used to express energy content |
| 2. |
How many calories are
there in a pound of body fat? |
| |
There are 3500 calories per pound of
body fat. In order to lose the stored pound of body
fat you need to lose 3500 extra calories. Therefore,
if the daily calorie intake is reduced by 500 less than
what the body requires, the stored up fat has to be
utilized for energy. Since the energy mechanism is complex
energy, requirements can vary for individuals.
The fitness level, motivation levels, present energy
stores, exercises, nutritional levels and genetic predisposition
determines the energy requirements of the body. A low
calorie diet can be the simplest form of dieting to
burn up some of the calories. |
| 3. |
How many calories are
there in a gram of food? |
| |
| Food Source |
Calories |
kilojoules |
| Protein |
4 |
16.7 |
| Fat |
9 |
37.7 |
| Carbohydrate |
4 |
16.7 |
There are 3500 calories per pound of body fat. In order
to lose the stored pound of body fat you need to lose
3500 extra calories. Therefore, if the daily calorie
intake is reduced by 500 less than what the body requires,
the stored up fat has to be utilized for energy. Since
the energy mechanism is complex energy, requirements
can vary for individuals.
Each gram of fat consumed provides more than twice as
many calories as a protein or carbohydrate. A gram of
fat is equal to 9 calories. 3500/9 = 389. It would conclude
that there are 389 grams in one pound. But there are
454 grams. The adipose tissue has other elements like
connective tissue, water and protein. And the nutritional
analysis of food given is pure.
On another approach, 3500/454=7.7 calories. Here a gram
of body fat contains 7.7 calories where as 9 calories
are found in pure fat. The difference comes when we
consider the body fat containing water, which has no
calories.
In order to avoid the confusion, it is easy to use 3500
calories per pound figure when dealing with fat burned
by activity. And when dealing with the nutrient content
of food, use 9 calories per gram figure. |
| 4. |
How many calories do
I need? |
| |
The basal
metabolic rate, energy expended during physical
activity and the thermic effect of food are the three
components, which make up the body's energy expenditure.
Adding these would accurately tell you the calorie requirement
for your body each day. |
| |
BMR [Basal Metabolic Rate]:
About 60-70% of the body's energy supports the ongoing
metabolic work of body's cells. It includes maintaining
body temperature, respiration and heart beat. |
| |
For males: You have to multiply the body
weight by 10. Then add double the body weight to this
value. |
| |
For females: You have to multiply body
weight by 10 and add the body weight to this value. |
| |
Energy spent during physical
activities: It contributes to about 20- 30%
of energy outputs. |
| |
Thermic effect of food:
The energy required to digest food is referred to as
TEF. TEF= total kilo calories consumed multiplied by
10%. |
| |
Easy way
Using your current weight and the type of activities
you follow, estimate the calories you would burn in
a day: |
| |
Total 2088 calories in 24 hours
Female 25. 5'2, 120lb: BMI=21.9, BMR=1, 350, RMR-1,243 |
| |
| Activities |
Time |
Calories |
| Sleeping |
8 hours |
392 calories |
| Offive Works |
8 hours |
653 calories |
| Driving |
1 hour |
109 calories |
| Food Preparation |
1 hour |
136 calories |
| Eating, Sitting |
1 hour |
82 calories |
| Shower |
30 minutes |
54 calories |
| Cleaning |
30 minutes |
82 calories |
| Shopping |
30 minutes |
63 calories |
| Walking |
30 minutes |
82 calories |
| Running 6mph |
30 minutes |
272 calories |
| Dressing |
30 minutes |
54 calories |
| Watching TV |
2 hour |
109 calories |
|
| |
When calculating the amount of calories
you need in a day, do not add your BMR or RMR as they
are needed only to calculate the calories burned during
the period. |
| 5. |
What is the Thermic
effect of food? |
| |
Commonly known as thermic effect, it
is the increment in energy expenditure above resting
metabolic rate due to the cost of processing food for
storage and use. In simple terms, it is the energy expended
by our body in order to eat and digest. We expend energy
by burning calories. The common number to estimate the
extent of thermic effect of food is 10% of caloric intake
of a given time period. However, there will be variations
in the effects due to difference in the food components.
|
| |
Dietary fat has little thermic effect.
Therefore, it is very easy to process. Protein is difficult
and it has a larger thermic effect. |
| |
Raw celery and grape fruit take more
energy than what is contained in the food, to digest. |
| |
Aerobic training and anaerobic weight
training can increase the thermic effect of food. |
| |
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