Fat. It can be a delicious contribution to your plate but when it comes to our bodies, we’d rather steer clear. But, before any of us begin working towards that summer physique, we should ask ourselves if eliminating fat really is an ideal method.
It is common to confuse body fat with dietary fat, hence the belief that fat consumed through food makes you fat.
Is this really the case?
All fats are not equal, discover the difference between the different types of lipids!
WHAT IS A LIPID?
Lipids are the molecules that make up the fatty matter of living beings.
Better known as fats, lipids can be differentiated from each other thanks to their molecular structure.
There are a number of different types of lipids such as:
It is important to note that 95% of dietary lipids are triglycerides.
What is a triglyceride?
It is a molecule (a lipid) that has 3 fatty acids attached to a glycerol molecule. Glycerol has little nutritional value. These are the fatty acids that we should focus on. They are the ones that are important for the balance of the body, and that give fats their properties.
So, what is a fatty acid?
During digestion, enzymes will “cut” the triglycerides to detach the fatty acids from the glycerol. This will then release the free fatty acids so that they can pass through the intestinal barrier.
WHAT ARE THE MAIN ROLES OF LIPIDS?
Once absorbed by the intestine, fatty acids can serve as a source of energy for the muscles. With 9 kcal per gram of fat, they are the most energetic nutrients. In comparison, 1 gram of protein and carbohydrates provide 4 kcal respectively.
Their role is not only energetic. Fatty acids are structural constituents of cell membranes, especially neurons. The brain, thymus and retina are the organs richest in fatty acids.
They will have an important role in the development of some of our essential hormones, such as sex hormones. For example, cholesterol, whether it is of food origin or manufactured by the liver, is used to make essential substances such as bile (digestion), sex hormones (progesterone, testosterone, estradiol) or stress hormones (cortisol). It is also an indispensable component of cell membranes.
They also have an essential role in the transport of certain proteins and hormones in the blood. We can also add that dietary fats serve as a vehicle for fat-soluble vitamins A, D, E, K (example: vitamins A and D in butter, vitamin E in vegetable oils).
THE DIFFERENT TYPES OF FATTY ACIDS
The terms saturated and unsaturated are used to differentiate the chemical structures of fatty acids. They are distinguished from each other by the number of carbon atoms and the number of bonds.
It is this structure that will condition the properties of each fatty acid:
- When a fatty acid has no double bond, it is said to be “saturated”.
- When a fatty acid has a double bond, it is said to be monounsaturated.
- When there are multiple double bonds, it is called “polyunsaturated”.
1. Saturated fatty acids
Wrongly demonized during the last decades (in particular by different studies with biases and not taking into account different parameters), saturated fats do not increase cholesterol nor the risk of cardiovascular disease in reasonable quantities. They remain essential for our organism.
Saturated fats provide us with energy, maintain the structure of our nerve cells and promote the production of many essential hormones.
Indeed, it is all a question of quantity and especially of the quality of the food we ingest!
On the other hand, excess saturated fat may increase cardiovascular risk in some people when combined with other factors such as a diet too high in salt and carbohydrates.
2. Monounsaturated fatty acids (omega 9)
Monounsaturated fatty acids are part of the lipids that are very important for the body. Even if they are not essential because the body knows how to synthesize them, a sufficient dietary intake can have many benefits on the body. Indeed, omega 9 promotes cardiovascular health (protective role on the cardiovascular system) and prevents certain metabolic diseases.
The advantage is that we are rarely deficient in omega 9 because they are present in many foods (vegetable oils and oilseeds), and our body knows how to make them from other sources of lipids.
3. Polyunsaturated fatty acids (omega 3 and 6)
Omega 3 and Omega 6 are fatty acids that are essential for the proper functioning of the body. They are part of the constitution of cell membranes, but they also play a role in many biological reactions, particularly hormonal and immune.
Some of these fatty acids are “essential” because the body cannot make them itself. Some of these fatty acids are “essential” because the body cannot make them itself, so they must be provided by the diet.
The ideal is to bring omega 3 and omega 6 every day to provide our body with all the resources it needs. But in today’s world, our consumption is unbalanced. While the recommended intake is 4 times more omega 6 than omega 3, we currently consume up to 20 times more omega 6 than omega 3!
An excessive consumption of omega 6 can harm the properties of omega 3, it provokes competition and can therefore contribute to the development of certain diseases.
It is therefore necessary to favour omega 3 and limit omega 6.
4. Trans fatty acids
Trans fatty acids are unsaturated fatty acids with at least one double bond in the trans position, unlike unsaturated fatty acids synthesized by the body with double bonds in the cis position.
Some trans fatty acids are naturally occurring. They are produced in the stomachs of ruminants (cows, sheep) by the bacteria that reside there. These fatty acids are then incorporated into the animals’ body fat and milk. They are therefore present in meat, milk and dairy products and pose no health risk.
Other trans fatty acids are of technological origin. They are synthesized through industrial processes such as the hydrogenation of vegetable oils. This type of process allows fats to pass from the liquid state to the solid state, which facilitates their use and storage and makes them less sensitive to oxidation.
Hydrogenation is an industrial process that modifies the configuration of unsaturated fatty acid molecules.
Trans fatty acids of industrial origin should be avoided as much as possible. Their consequences on health are worrying, even when consumed in small quantities: they can considerably increase the risk of cardiovascular disease.
5. What about cholesterol?
Cholesterol is not a fatty acid, but is considered a blood lipid. It does not provide energy.
The liver produces about 75% of the cholesterol in the body, and food provides the remaining 25%.
Cholesterol is essential to the body because it is involved in the composition of cell membranes, the formation of certain hormones and bile (lipid digestion).
It is important to keep in mind that foods do not contain “good” or “bad” cholesterol.
In fact, both types of cholesterol are more like carriers of cholesterol in the blood. HDL (high-density lipoprotein) transporters have a “clearing” effect on the arteries, while LDL (low-density lipoprotein) transporters, when present in excess, have a “blocking” effect.
WHICH FOODS SHOULD YOU GO FOR?
As far as lipids are concerned, here are some foods that you can include in your diet.
Foods rich in saturated fats:
- coconut oil
- meat (from grass-fed animals)
- butter (raw if possible)
- fresh milk
- raw milk cheese
Foods rich in omega 9:
- oilseeds (almonds, walnuts, hazelnuts, macadamia etc.)
- olive oil
- goose and duck fat
- oleic sunflower oil
Foods rich in omega 3:
- oily fish (sardines, salmon, mackerel, etc.)
- linseed oil
- rapeseed oil
- hen eggs fed with flax seeds
Nevertheless, certain types of foods should be limited, such as :
- Deli meats
- Oils rich in omega 6 (corn, soybean, safflower, canola, peanut, sesame)
- Pastries and baked goods
- Cakes, cookies, ice cream, and other industrial and processed products
- Hydrogenated fats
- Industrial cheeses
- Fried and cooked fats
There, is no food to banish from your diet, it’s all about balance!
Eating high-fat foods does not mean that you will necessarily store fat in your body. It’s a big shortcut!
Nor should you be afraid to eat foods containing cholesterol!
You have to contextualize and adapt your intake in an individualized way. Each person is different.
It is also important to keep in mind that the quality of food plays a major role in the assimilation of nutrients and the health of your body.
Finally, try to favour organic, local, minimally processed and industrial foods.
Article written by Yann Harstein, dietician at Foodvisor.