Food is necessary to provide nutrients for our body and comes mostly from animal or plant sources. By its assimilation we get the energy and are able to maintain the right body functioning. It contains nutrients such like proteins, carbohydrates (sugars), fats, vitamins and minerals.
Digested food, water and minerals are absorbed from the intestine. They cross the mucosa and go into the bloodstream where they are carried to other parts of the body for different chemical functions of for the storage. The later depends upon different kinds of nutrients.
As mentioned above, every cell in our body needs energy to function in its optimal state.
Calorie has a bad reputation nowadays but it is of course no more than a measure unit to evaluate the energetic value of the food.
A calorie by the definition means the quantity of heat energy needed to raise the temperature of one kilogram of water from zero to one degree Celsius.
Calories became scientifically defined in the year 1925 in joules. The later are units to describe the amount of work done to an object with the force of one Newton through a distance of one meter. This is why you sometimes see kilocalories being called kilojoules.
One calorie is 4,18 joules (1 joule is 0,239006 calorie).
Calories are therefore the energy that fuels our bodies for all of our body functions. Many of us don’t know how many calories our body needs just to maintain our life functions even if we would lay still the whole day but just for the functioning of the key organs like the brain, heart, kidney, liver and lungs and other necessary metabolic processes. This amount of calories is called the resting metabolic rate (RMR) calories and its value depends on gender, age, height, weight and activity level (muscle mass).
An adult human body needs between 1000 to 1400 of RMR calories. But additional energy is needed for our active part of life, which amounts between 400 to 600 calories daily.
Therefore you need to keep the balance between what you really burn per day including your activity. All access of energy will be stored by your body for the “hard times” as a body fat and you might be overweight.
The number of calories in a food depends on the amount of energy the food has.
|Food type (1gram)||Amount of energy (kcal)|
Water is not a food but it is an indispensable molecule for any living cell, except for the inactive viruses, which are a separate form of life from cellular organisms.
Human body consist of approximately 60% of water. We get it directly by drinking or with other ingested liquids and with the food. It is an important solvent medium in which salt and a lot of nutrients are dissolved.
The function of water is that it brings nutrients, like are minerals, vitamins, to the cells, which help in regulation of many body processes, as well as act in nerve responses; 92% of volume of blood is water etc. Another function of water is that it flushes toxins away that are aggregating in organs. It provides a suitable environment for those organs where moist is necessary, for example for the efficient exchange of gas molecules between the environment and body. Such are nose, throat, lungs; also ear needs some moist environment. Or mouth is further example where water is excreted together with enzymes from salivary glands to start the digestion. Water is in waste majority absorbed from the small intestine. On the other hand we constantly lose the water from the body through breathing, perspiration, urine and defecation.
For a proper body functioning you need to keep the lost and the needed water quantity in balance. Therefore it is very important that you replace the lost water and drink enough of it each day. The recommendation for an adult person in the temperate climate is to drink about 2 litres of water daily.