HOW TO PLAN A GOOD DIET AND MAINTAIN A GOOD HEALTH AND STIMULUS-RESPONSIVE BODY SYSTEM.[FOOD CHEMISTRY]

As you all know,the energy the body needs for metabolic and physiological processes come from nutrients in food we eat and the unit of energy in this food is called calorie..
1 gram of carbohydrate = 4 kcalories
1 gram of protein = 4 kcalories
1 gram of fat = 9 kcalories ..
Alcohol contains 7 kcalories in one gram but it is NOT considered a nutrient.

Note that a calorie is the amount of heat needed to raise the temperature of 1 gram of water by 1degree celsius and 1000 calories equals 1 Kcalories.... kcalories is the unit used in the nutritional context..The conversion factor used to convert calories to joules are numerically equal to expressions of the specific heat capacity of water in j/g or j/kg..

Adults
Women need 1,800 to 2,000 calories per day.
Men need 2,200 to 2,400 calories per day.
They may need more if they are very active.

Children
Girls aged 9 to 13 need 1,600 calories per day.
Boys aged 9 to 13 need 1,800 calories per day.
Children may need 400 more calories each day if they are moderately physically active.
Very active boys and girls(those who work more than 3 miles, or 5 kilometers, per day in addition to participating in regular daily activities) may need to consume even more..

Through metabolism the body breaks the chemical bonds between atoms of nutrients and energy is released.These Energy can be used to build new compounds, move the body or escape as heat.
With the above values of calories..you can give your own estimation on the calorise of food you consume everyday,by so doing you can watch your weight,maintain a good health and a stimulus-responsive body system.