Make no mistake: When we say "fat is life", it doesn't mean that hamburgers, sausages, cheese and all fatty and sweet products have to be part of your daily life.
To function optimally, our body needs different sources of food called macro-nutrients: carbohydrates (sugars), proteins (proteins) and lipids (fats). On average, fat should account for about 25-35% of the total calories provided by our diet.
The big problem is that fat has been systematically singled out for the past few decades, accused of several evils, and the food industry has had a field day developing "0% fat" products. But this is an aberration from a nutritional and health point of view. Fats are vital and fundamental for the proper functioning of our bodies! Of course, if they are of good quality. Some fats are "empty calories"; in other words, they do not provide any nutrients to our bodies as they have been transformed, modified, or heated. So when we talk about "fats", not all fats are the same. They do not have the same nutritional qualities, the same impact on our body's health, and their use in cooking also differs.
The so-called modern diet contains a lot of low-quality saturated fats, which often come from the animal world: meat, eggs, dairy products, but also from the plant world in some cases, such as palm oil, all of these are found in large quantities in all (ultra)processed products. There are, therefore several types of fat or fatty acids.
Saturated fatty acids are found in:
In our society, there is a tendency to over consume them. However, these fatty acids are not harmful if consumed in reasonable quantities (we need them to live and unction), as they provide energy and vitamins (A, D, E, K). When consumed in excess, however, they encourage extra weight and cardiovascular problems and increase the development of neurodegenerative and/or inflammatory diseases(cancers, multiple sclerosis, Parkinson's disease, etc.) and the onset of diabetes.
Unsaturated fatty acids are not very present in our western diet, as most industrial food products are devoid of them. Yet they should represent 3/4 of our fatty acid intake.
There are three main families of unsaturated fatty acids:
Omega-6 and omega-3 are often grouped under the same name: "essential fatty acids" or "polyunsaturated fats". They are said to be essential because, unlike the previous ones, our body cannot produce them by itself. They must therefore be supplied through the diet. If they are not provided, we may develop a deficiency after a certain period of time, which can present in various symptoms or dysfunctions.
Omega-3, through alpha-linolenic acid, has great anti-inflammatory and anti-allergic properties. It increases the level of good cholesterol, thus protecting the blood vessel walls and blocking the creation of blood clots. It intervenes in the regulation and balance of the nervous system and thus has an impact on our ability to manage stress, and the quality of our sleep. These precious nutrients fight against depression and play a protective role for neurons, reducing the occurrence of cognitive disorders such as memory loss. They reduce the risk of autoimmune diseases and excess weight, and improve tolerance to chemotherapy and radiation. Omega-3 can be found in fatty or semi-fatty fish (sardines, mackerel, herring, tuna, salmon, swordfish, but also crustaceans, krill, etc.), in hemp, camelina, flax, walnut, wheat germ and rapeseed oils, in vegetables such as broccoli, spinach, lettuce, mesclun, rocket, cabbage and purslane, and finally in oilseeds such as walnuts and almonds. It goes without saying that the fresher and better the products, the better we can meet the needs of our body cells.
The omega-6s, through linoleic acid, enable the synthesis of other essential polyunsaturated fatty acids: GLA, DGLA, arachidonic acid. But they also play the role of precursors in the synthesis of certain molecules such as prostaglandins or leukotriene.
The plant omega-6s are mainly beneficial, since they mainly produce series 1 prostaglandins: they protect the arteries and the heart, they modulate allergy and inflammation, they allow good hormonal regulation, they help to regulate neurotransmitters and therefore have an interesting action on hyperactivity and addictive behaviours. They are found in safflower, grapeseed, sesame, sunflower, corn and soybean oils, as well as in borage, evening primrose, hemp and spirulina.
As for animal omega-6s, they should be moderated, since they produce series 2 prostaglandins, which are pro-inflammatory, increase the cardiovascular risk factor, and increase the allergic syndromes. They are found in meats, cold cuts, all dairy products (cheese, cream, butter, etc.).
The problem is that today, we have a poor omega-6 / omega-3 ratio overall: conventional food contains far too much inflammatory omega-6 and saturated fat, and not enough omega-3 and omega-9. The balance of absorption between the different polyunsaturated fats is then broken. Knowing that a deficiency in omega-3 can lead to neuro-psychological disorders, membrane disorders (drying of the skin and mucous membranes), inflammatory processes, hormonal imbalances, hypertension and depression. The aim is to achieve a balance that meets the body's needs, and therefore to optimise the ratio of omega-6 to 3: we reduce the quantities of foods rich in omega-6 while increasing the quality of their origin, and also increasing the foods rich in omega-3. Eggs, oily fish, butter (raw and organic quality) and meat (organic quality) are very interesting for the assimilation and storage of fat-soluble vitamins (vitamins A, D, E, K). So sources of omega-6 should not be banned but should be consumed differently: less in quantity, better in quality.
We have just given a brief overview of animal and vegetable fats, omega-9, 6 and 3. But there are also fatty acids that are found everywhere and which are very detrimental to health, which predispose to disease states: these are the so-called trans fatty acids. They are said to be "trans" because at least one double bond of these fatty acids is in the "trans" position. They are mainly found in processed, ultra-processed and prepared products of the food industry, in particular as preservatives and stabilisers, in snack foods, in margarines, and in fried foods. They can also be formed by cooking with poor quality vegetable oils. They do not nourish our cells. According to the World Health Organisation, they cause 500,000 deaths per year.
So what should we eat? And how to eat them?
As far as oils are concerned, conventional (non-organic) oils follow a specific manufacturing process that allows for an optimal yield in a short period of time: the seeds used for their manufacture are crushed, then heated to a high temperature, then treated with solvents. The result is a product with an unpleasant smell and taste. To remedy this, manufacturers refine the oils, i.e. they put the oil through a series of operations involving sulphuric acid, soda, synthetic antioxidants and other hydrogens. The resulting oil is denatured. It is devoid of nutrients and is biologically inactive. The first criterion to be favoured is therefore the organic label, which guarantees much more than a product "without" (fertilisers, pesticides, fungicides, etc.). The second criteria is the label 'virgin', which guarantees that the product has been obtained solely by mechanical means and has not been chemically treated or refined. However, this designation does not protect the product from overheating during production. Thus, the third criteria guaranteeing a good quality product is the designation "first cold pressed". This guarantees that the product has not been heated during the manufacturing process and therefore retaines all its original nutrients. As for animal fats, which are found in fish, meat, eggs and dairy products, their consumption must be rational and above all of the best possible quality, in other words organic and local if possible.
All oils have one thing in common: they are made up of 100% fat. There is no one oil that is lighter than another. Their difference lies in the nature and quality of their fatty acids. Ideally, one would choose two to four oils for the weekly consumption, and to vary. Depending on your profile, your consumption habits and your tastes, some oils are more suitable and recommended than others. For example, you can have olive oil at home for cooking, as well as hemp, flax and walnut oil, for seasoning salads, raw vegetables, soups, soft-cooked vegetables (to be added after cooking). In the kitchen, oils rich in omega-9 are preferred for gentle cooking (casseroles, stewing, baking, greasing pie and cake tins, etc.). Olive and coconut oils are particularly recommended here. Those rich in omega-6 and omega-3 can be used for dressings (salads, etc.) and can also be used on hot dishes: simply pour them onto the plate, after cooking the food, just before eating. They should be kept in the fridge, as their fatty acids are very fragile and oxidise very quickly when exposed to heat and light.