The
last one in the series of our requirement for food is the adequate calories.
Calories:
What They Are and Why You Need Them
What calories are?
Calories
are simply a measure of the energy in the foods that you eat. Your body
doesn’t use energy to raise the temperature of water, but you need energy
(measured as calories) to fuel all of your daily functions – your basic
metabolic processes, as well as all the activity you engage in throughout the
day. But in order for your body to tap into this energy, it first has to be
released from the foods you eat.
Why we
need calories?
Providing
energy to the body is often compared to the way you provide energy to your car.
When you put fuel in your car’s tank, there is energy (which, by the way, could
also be measured in calories!) “locked up” in the gasoline. But just having gas
in the gas tank isn’t enough to make the car move. In order for that to happen, the fuel has to be ignited
in the engine, which releases the energy from the gasoline – energy that can be used to
propel the car.
Similarly, the
food (fuel) that you eat has energy – in the form of calories. These calories
are absolutely necessary to life. Your resting metabolic rate (the
number of calories your body uses every day for the most basic processes just
to keep you alive) accounts for about 75 percent of the calories your body uses
every day. The remaining you burn during the day are used to fuel your muscles
as you move around throughout your day and engage in exercise, and a very small
amount that is used to digest and process your food.
What is the best source to meet requirements of
calories?
The food (fuel) that you eat has energy. The “big three”
macronutrients – protein, fat and carbohydrate – provide the majority of the
calories we eat.
What is the estimated
requirement of calories for our body?
Estimated amounts of
calories needed to maintain energy balance for various gender and age groups at
three different levels of physical activity are summarise in the table (vary depending upon age). Based on dietary intake data or evidence of public health problems,
intake levels of the following nutrients may be of concern for:
Sedentary means a lifestyle
that includes only the light physical activity associated with typical day-to-day life.
Moderately active
means a lifestyle that includes physical activity equivalent to walking about
1.5 to 3 miles per day at 3 to 4 miles per hour, in addition to the light
physical activity associated with typical day-to-day life
Active means a
lifestyle that includes physical activity equivalent to walking more than 3
miles per day at 3 to 4 miles per hour, in addition to the light physical
activity associated with typical day-to-day life.
Sedentary
|
Moderately Active
|
Active
|
|
Child 2-18 yrs
|
1000-1800
|
1200-2000
|
1200-2400
|
Female 19+ yrs
|
2000-1600
|
2200-1800
|
2400-2000
|
Male 19+ yrs
|
2400-2000
|
2600-2200
|
3000-2400/2800
|
How to
calculate calories in a serving of food?
The food we eat has calories. A gram of protein has 4 calories’
worth of energy; a gram of carbohydrate also has 4 calories locked away. Fat is
a more concentrated source of energy – each gram of fat contains 9 calories of
energy. There’s one other calorie source that’s alcohol.
A gram of pure alcohol has 7 calories, nearly as calorie dense as pure fat.
Which food you should avoid?
Let me say in
brief
If you were to
look at the nutrition facts panel on a serving of potato chips, it might say
that the chips have 7 grams of fat, 17 grams of carbohydrate, and 2 grams of
protein, and 140 calories.
Since fat has 9 calories per gram, the 7 grams of fat
contribute 63 calories to the total; since carbohydrate has 4 calories per
gram, the 17 grams of carbohydrate add another 68 calories; and the 2 grams of
protein contribute just 8 calories. When you add up all the calories (63, 68
and 8) it totals 139 calories (nutrition facts panels are allowed to round
their numbers).
Most foods contain calories from more than one source –
with the exception of foods like oils (all fat calories) or sugars (all
carbohydrate calories).
Whether calories are bad for you?
Calories aren't bad for you. Your body needs calories for
energy. But eating too many calories — and not burning enough of them off
through activity — can lead to weight gain. Most foods and drinks contain calories.
Key Recommendations
for Specific Population Groups
- Adults:
calcium, potassium, fiber, magnesium, and vitamins A (as carotenoids), C,
and E,
- Children
and adolescents: calcium, potassium, fiber, magnesium, and vitamin E,
- Specific
population groups (see below): vitamin B12, iron, folic acid,
and vitamins E and D.
- People over age 50. Consume vitamin B12 in its crystalline form (i.e.,
fortified foods or supplements).
- Women of childbearing age who may become
pregnant. Eat foods
high in heme-iron and/or consume iron-rich plant foods or iron-fortified
foods with an enhancer of iron absorption, such as vitamin C-rich foods.
- Women of childbearing age who may become
pregnant and those in the first trimester of pregnancy. Consume adequate synthetic
folic acid daily (from fortified foods or supplements) in addition to food
forms of folate from a varied diet.
- Older adults, people with dark skin, and
people exposed to insufficient ultraviolet band radiation (i.e.,
sunlight). Consume
extra vitamin D from vitamin D-fortified foods and/or supplements.
What we should eat?
- More dark green vegetables, orange vegetables, legumes, fruits, whole grains, and low-fat milk and milk products.
- What we should avoid?
- Less refined grains, total
fats (especially cholesterol, and saturated and trans fats),
added sugars, and calories.
