What are calories

What are calories?
Calories are the unit measurement of energy for food (1 calorie = 4 joules). The main sources in food are carbohydrates, protein and fat.

We eat so that we get nutrition and, more importantly, energy to sustain our activities, bodily functions and life itself. Every breath you take, every movement requires a certain amount of energy.

How Calories Influence weight gain and weight loss
Losing or gaining weight is all about energy, and all about CALORIES.

Wanna lose 1 pound of fat? Well than you gotta somehow burn 3500 calories.

If you supply your body with more energy (food) than it needs, the surplus can’t just disappear. It will be stored (you could call it potential energy) as fat. So what is the impact in terms of weight gain or loss?

Energy and weight gain: People who gain weight are supplying too much energy into their system. In other words, based on their natural metabolic rate and daily activities, they are eating more than they should. Hence the excess is stored as fat.
Energy and weight loss: When people don’t eat enough food to create energy to support their daily activities, their body will tap into reserves (fat) to balance the equation.
How many calories Do you need per day?
Everyone should generally know how many calorie they need per day and the factors that influence it. There are different formulas to calculate this but let’s keep it practical.

One’s daily calorie requirement depends on various factors:

Gender: Males generally require more energy compared to women, having been intended by Nature to do the heavier work
Age: The older you become, the fewer calories you need because the natural metabolic rate slows down
Weight: The more you weigh, the more calories your body needs to keep alive (just as a heavier car consumes more fuel); this is also why people find it harder to lose weight after dropping a few pounds
Level of Activity: Keeping fit ensures that you have more calories (energy) going out; being active also plays a big role in lifting your overall metabolic rate
Basal Metabolic Rate (BMR)
The BMR is the amount of energy you need to sustain your life. This includes your breathing, organs and everything else you need to keep alive:

Men: BMR = 66 + (13.7 x wt in kg) + (5 x ht in cm) - (6.8 x age in years)

Women: BMR = 655 + (9.6 x wt in kg) + (1.8 x ht in cm) - (4.7 x age in years)

Daily Calorie Requirement (DCR)
Next, we factor in how active the person is, by using the Activity Multiplier:

Sedentary = BMR x 1.2 (little or no exercise, desk job)
Lightly active = BMR x 1.375 (light exercise/sports 1-3 days/wk)
Moderately active = BMR x 1.55 (moderate exercise/sports 3-5 days/wk)
Very active = BMR x 1.725 (hard exercise/sports 6-7 days/wk)
Extra active = BMR x 1.9 (hard daily exercise/sports & physical job or 2xday training)
Daily Calorie Requirement (DCR)
You are a 30 year old female, 30 years old, 5' 6 " tall (167.6cm) and weigh 120 lbs (54.5 kg).

Your BMR = 655 + 523 + 302 - 141 = 1,339 calories/day
Your DCR = 1.55 x 1339 = 2,075 calories/day

Dipetik dari Cekodok.com