are counting them and cutting them, and you would be hard-pressed to find
something at your supermarket that does not list its calories per serving
somewhere on the package. But what is a calorie is?
A calorie is a unit of energy. We tend to associate calories
with food, but they apply to anything containing energy. A gallon (4 liters) of
gasoline contains about 31,000,000 calories.
calorie is the amount of energy, or heat, it takes to raise the temperature of 1
kilogram (2.2 pounds) of water 1 degree Celsius (1.8 degrees Fahrenheit). One calorie is equal to
4.184 joules, a common unit of energy used in the physical sciences.
of us think of calories in relation to food. It turns out that the calories on a
food package are actually kilocalories (1,000 calories = 1 kilocalorie). The
word is sometimes capitalized to show the difference, but usually not. A food
calorie contains 4,184 joules. A can of soda containing 200 food calories
contains 200,000 regular calories, or 200 kilocalories. A gallon of gasoline
contains 31,000 kilocalories.
same applies to exercise. When a
fitness chart says you burn about 100 calories for every mile you jog, it means
100 kilocalories. So when I say calorie, what I really mean to say is
We all need energy to
survive. The number of calories in a food is a measure of how much potential
energy that food possesses. A gram of carbohydrates has 4 calories, a gram of
protein has 4 calories, and a gram of fat has 9 calories. Foods are a
compilation of these three building blocks, so if you know how many
carbohydrates, fats and proteins are in any given food, you know how many
calories, or how much energy, that food contains.
you look at the nutritional label on the back of a package and it says160
calories, this means that if we were to pour this into a dish, set it on fire
and get it to burn completely, the reaction would produce 160 kilocalories (food
calories are kilocalories) or enough energy to raise the temperature of 160
kilograms of water 1 degree Celsius.
Your body burns these
calories through metabolic processes, by which enzymes break the carbohydrates
into glucose and other sugars, the fats into glycerol and fatty acids and the
proteins into amino acids. These molecules are then transported through your
bloodstream to your cells, where they are either absorbed for immediate use or
sent on to the final stage of metabolism in which they react with oxygen to
release their stored energy.
So just how many calories do your cells need to function?
Well it differs for everyone. You
may notice on the nutritional labels of the foods you buy that the percent daily
values are based on a 2,000 calorie diet, but your body might need more or less
than 2,000 calories. Height, weight, gender, age and activity level all affect
your caloric needs.
There are three main factors involved in calculating how many
calories your body needs per day, Basal metabolic rate, Physical activity
and thermic effect of food.
basal metabolic rate (BMR) is the amount of energy your body needs to function
at rest. This accounts for about 60 to 70 percent of calories burned in a day
and includes the energy required to keep your heart beating, your lungs
breathing, your kidneys functioning and your body temperature stabilized. In
general, men have a higher BMR than women. One of the most accurate methods of
estimating your basal metabolic rate is the Harris-Benedict formula which
is explained in my book
‘Get fit Stay Fit’
second factor physical activity, consumes the next highest number of calories.
Physical activity includes everything from making your bed to jogging. Walking,
lifting, bending, and just generally moving around burns calories, but the
number of calories you burn in any given activity depends on your body weight.
Check out my fitness calculators on my site…or the formulas in my book so that
you can personalize your calories burned per activity.
final number of calories your body burns is the thermic effect of food.
This is the amount of energy your body uses to digest the food you eat.
It takes energy to break food down to its basic elements in order to be
used by your body. To calculate the number of calories you expend in this
process, multiply the total number of calories you eat in a day by 0.10, or 10
total number of calories your body needs in a day is the sum of these three
So if you take in more or fewer calories than your body
burns, you either gain or lose fat. And for every extra 3,500 calories stored by
your body you gain 1 pound of fat. If you burn 3,500 more calories than you eat,
whether by exercising or eating less, your body converts 1 pound of its stored
fat into energy to make up for the deficit.
thing about exercise is that it raises your metabolic rate not only while you're
huffing and puffing on the treadmill, it continues to function at a higher
level, burning an increased number of calories, for about two hours after you've
does it matter where your calories come from?
If you eat exactly the number of calories that you burn and you are only
talking about your weight, the answer is no. A calorie is a calorie. A protein
calorie is no different from a fat calorie. They are simply units of energy.
If you burn what you eat, you will maintain your weight, and if you burn
more than you eat, you will lose weight.
if you do not burn all of the calories you eat and you're not trying to gain
weight, you would probably want your extra calories to come from carbohydrates
or proteins instead of fats. Fats are easier to store as fat.
Your body expends more energy on the chemical processes that convert
carbohydrates and proteins into fats, meaning that some calories are actually
burned in the storing process.
your talking about
nutrition, it definitely matters where your calories come
from. Carbohydrates and proteins are healthier sources of calories than fats.
Although your body does need a certain amount of fat to function properly, like
to absorb the vitamins you ingest, an excess of fat can have serious health
consequences. A maximum of 30 percent of our daily calories should come from
fat. So, if you eat 2,000 calories a day, that's a maximum of 600 calories from
fat, or 67 grams of fat, per day. However, if you strive to get 25 percent of
your daily calories from fat it is better. That's 56 grams of fat per day (500
calories) for a 2,000 calorie diet.
I know you want to get in
shape and look great. Whatever
your fitness goal…to slim down…gain muscle…tone your arms or
flatten your tummy…I’m here to help you accomplish your goals and
to improve your fitness level. If you have enjoyed this article and
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