How does your body use food?
What's food?
Food is defined as a mixture of substances that your body ingests to sustain itself and to perform all its essential functions. All food is made of chemical compounds, called nutrients. Scientists have divided nutrients into macronutrients and micronutrients.
What are macronutrients and micronutrients?
Macronutrients are the nutrients that your organism needs in the largest amount. The main function of macronutrients is to provide you with energy, but they also build your muscles, keep you warm, get you moving, and much more. Macronutrients are three: carbohydrates, proteins and fats.
On the other hand, micronutrients are called this way because your body needs smaller quantities of them. They don’t directly give you energy, but they help your organism assimilate macronutrients and perform other tasks, such as preventing the onset of diseases. Your organism can’t produce them itself, so you have to ingest micronutrients daily.
What are carbohydrates?
Carbohydrates are the most naturally occurring biomolecules. A biomolecule is a group of atoms that constitutes a living being and makes its biological processes possible. Carbohydrates are the main source of energy for your body. They can be stored to provide energy resources, and they are also a part of the cell lining.
They can be split into simple and complex, according to their chemical complexity, which influences how quickly they are absorbed by your organism.
Simple carbohydrates include:
– monosaccharides: galactose, fructose and glucose;
– disaccharides, which are made of two monosaccharides bonded together. The most known disaccharides are sucrose (glucose + fructose) and lactose (glucose + galactose).
When we eat simple carbohydrates they usually reach your blood in 15-20 minutes, giving us instant energy, which, however, doesn’t last long. Fruit, sugar, honey and candies contain simple carbohydrates.
Complex carbohydrates are polysaccharides, which means they are made of hundreds of monosaccharides bonded together. Because of that, their digestion lasts longer, so we use their energy more slowly and for longer. Complex carbohydrates are mainly three:
– amid, which is produced by plants through photosynthesis → wheat, pasta, bread, potatoes…
– glycogen, which is the amid stored in an animal’s liver and muscles → meat or fish
– fibre, which is not completely assimilable by your body. It’s important for your health and it modulates the absorption of other nutrients → fruit, vegetables, whole food, legumes…
What are proteins?
Proteins are long amino acids chains bonded together. Amino acids are organic compounds made of carbon, oxygen, hydrogen and nitrogen. Proteins are like bricks for your organism: they create body tissues and regulate the processes that take place in them. When in lack of other nutrients, your body could burn them to create energy, demolishing your muscles.
You can get protein through plant foods → legumes; or animal foods → meat, fish, eggs, dairies, milk…
What are fats?
Fats are biomolecules made of oxygen, carbon and hydrogen. They regulate the absorption of nutrients, hormone levels, blood pressure; they are thermal insulation and can be stored to be used as energy. Most of the fats we know are triglycerides, a chemical structure made of one glycerol molecule and three molecules of fatty acids.
We often hear about saturated and unsaturated fats, what does this mean?
It’s pretty easy:
– unsaturated fats have one or multiple double bonds between two of their carbon atoms. This makes them liquid and a healthier source of fat for your body. Indeed, they clean blood vessels. → seed oils, dried fruit, vegetable oil, fish…
– saturated fats are the opposite: they are solid and don’t contain double bonds. They have to be eaten in moderation because they can sediment in your blood vessels. → butter, cheese, meat…
What are vitamins?
Vitamins regulate most of the chemical reactions that happen in your body, including hormone levels, immune system reactions, or nutrient absorption. The main vitamin sources are fruit and vegetables.
Vitamins can be either water-soluble or fat-soluble.
– water-soluble vitamins, like B and C type, can dissolve in water. Since your body expels excess water, water-soluble vitamins aren’t storable, and must therefore be integrated daily through food.
– fat-soluble vitamins, which are A, D, E and K, can dissolve in fats. Your body stores these vitamins along with fat. For this reason, your organism can’t expel them if there’s an excess, so they can accumulate and lead to pathologies.
What are mineral salts?
Mineral salts are inorganic substances. They help your body build, grow and create tissues. As micronutrients, your organism can’t create them, and they are also continuously expelled through sweat, urine and faeces. Consequently, you need to introduce mineral salts into your body every day. If you lack mineral salts, it’s important to take supplements to fullfil your needs, especially if you’re a teenager who’s growing. Mineral salts are found in fish, meat, legumes, vegetables, dried fruits…
The salt we use in cooking is added to foods to spice or store them. Its consumption should be limited to less than 5gr per day, as it may cause serious health problems if eaten in excess.
What's water?
About 60% of your body weight is made of water: you can’t survive more than a couple of days without drinking. Water is part of food. The more water the food contains, the faster it’s going to go off. Water is essential to expel waste substances, through urine and sweat, and it’s a huge component of all your body tissues. You should drink about 1,2 to 2 litres of water per day.
What is metabolism?
The word metabolism represents the set of chemical processes carried out in your body to:
– break down the molecules to produce energy
– obtain the chemical structures needed by your cells
Metabolism and food are strictly connected: the chemical processes only take place if you eat. Since we are all different human beings, everyone’s metabolism is different and is determined by genetics as well as the type of life you lead.