how does a calorie function

[Guest guest]

i googled " process energy " to look for ways to optimize

energy perfomance in building design. and i stumbled

upon this article on how a calore functions in the

process of energy for humans. neat.

link to article

http://www.ehow.com/how-does_4574271_a-calorie-function.html

How does a calorie function, by Ysabel Doran

What is a Food Calorie?

The term calorie as it applies to food, is a bit removed

from the strict scientific definition. Physicists and

chemists use the word calorie to describe the amount of

energy required to heat 1 gram of water 1 degree Celsius.

Nutritionists, on the other hand, say a calorie is the

amount of food that would have to be burned to heat 1

kilogram of water one degree Celsius. So, a food calorie

is technically a kilocalorie.

Calories Provide Energy for the Body

In the body, food is not burned by fire, but is digested,

which, like burning, is a form of oxidation. Food molecules

are broken down and in the process, energy is released.

Food energy is used for tissue growth and repair, metabolic

functions, fighting infection and for muscle movement.

Not All Calories Are Equally Nutritious

Vegetables are nutrient rich. Cookies are nutrient poor.

Calories impart energy for body functions, but the body

also requires nutrients. Protein, vitamins and minerals

are the building blocks that the body uses to grow,

maintain and heal its tissues. Certain foods, like

butter or ice cream, contain a lot of calories, but

relatively few nutrients. The calories in these foods

are nutrient poor. Other foods, like fat-free cottage

cheese and spinach, offer a lot of nutrients with

relatively few calories. These calories are nutrient rich.

Unused Calories Are Stored as Body Fat

Too much butter or too many green beans--either will

result in extra body fat. Whether a calorie comes from

sugar, fat or protein, it delivers the same amount of energy-

precisely one calorie. The body uses the energy the same way,

no matter the source. Caloric energy that is not used for

muscle movement or other body functions is stored as body

fat. The amount of body fat is determined only by the

number of calories, not by the food source of the calories.

So, 500 extra calories from broccoli will result in the same

amount of stored body fat as 500 extra calories from ice cream.

The Type of Food Affects Calorie Absorption

The type of food does not determine the ultimate fate of a

calorie, but the molecular structure of food does affect

how quickly calories are absorbed. Simple molecules like

table sugar are easy to digest and will go into the bloodstream

almost immediately. Therefore, a sugar calorie must be used

almost immediately or be turned to body fat. Conversely, a

large protein molecule is more difficult to digest. So calories

from protein enter the bloodstream more slowly and can be used

over a longer period of time before being stored as body fat.

Nondigestible dietary fiber like that in whole grains,

vegetables and fruits also slows calorie absorption in the

digestive system.

Body Fat Stores Energy, Not Nutrients

Fuits, vegetables and nuts, all filled with nutrients, are

good weight-loss food. Extra fat that accumulates on the body

is not accompanied by a full complement of nutrients. In other

words, body fat is a nutrient-poor calorie source. When you

reduce calorie consumption to make your body use its own fat

for energy, be sure to eat foods that are rich in protein,

vitamins and minerals to make up for the nutrients not found

in body fat.