Our taste buds love it, but the fats have an appalling reputation in their greedy wake. Phew, they are back on the front of the stage, all haloed with real health benefits. We explain to you.
Saturated fatty acids, cholesterol , hydrogenated fats… do these words arouse a certain repulsion in you? Normal, we have long pointed out the harmful effects of lipids and concealed what they could bring to the body that needs it. For those who still doubt their importance, we give it a layer and we give you the good reasons not to feel guilty any more by seasoning your meals.
Science is also (sometimes) in the cabbage!
“In the 1960s, very skinny models started to be fashionable, but also low-fat products, skimmed milk, 0% fat foods. Cholesterol was the enemy to be destroyed, ”recalls Dr Alexandra Dalu, nutritionist. “Fats had not always been demonized, on the contrary, but on the basis of a study with dubious methodology, some scientists have made the link between consumption of fat, increased cholesterol levels, and explosion of cardiovascular diseases . This so-called “7 countries” study, conducted by Ancel Keys, seemed to show that a diet low in fat protected against heart disease. But she was biased! And yet it is on its results that we will rely for decades to decry lipids …
These owe another part of their bad reputation to their high calorie content: in fact, 1 g of fat provides 9 kcal, while 1 g of protein or 1 g of carbohydrates only provide 4. However, the The equation isn’t that simple: carbohydrates are less satiating than fat, they raise blood sugar (blood sugar levels), and can be stored as fat, while fat takes a long time to digest , and can also serve as energy in the muscles. Hence the interest of keeping them even in a weight loss diet. Moreover, more recent work has gradually rehabilitated fats . Their virtues depend on the type of lipids we are talking about.
A large family full of resources
Fat is useful as a whole, because it “allows the transfer of information between nerve cells, has an anti-inflammatory and even pain relieving role”, summarizes Dr. Dalu.
• So-called polyunsaturated fatty acids , which include on the one hand omega 3 (contained in fatty fish, linseed, camelina, walnut and rapeseed oils), and on the other hand omega 6(sunflower, corn, grape seed, soybean oils, etc.) play an important role. Omega 3s are divided into alpha-linolenic acid (ALA), eicosapentaenoic acid (EPA) and docosahéxaenoic acid (DHA). The first “helps to reduce the level of bad cholesterol and to increase that of the good”, indicates Dr. Laurence Plumey, nutritionist doctor. And the other two “help reduce mortality from coronary heart disease: they regulate heart rate and blood pressure and limit the risk of clogging your arteries.” They have many other advantages, whether in our platelets, the membranes of our neurons, our hepatic, retinal or cerebral cells. “For all these reasons, omega 3s must be considered useful and necessary in the prevention of cardiovascular diseases,neurodegenerative diseases, ”concludes Dr Plumey. Omega 6 has a role in the management of inflammation, but we must be satisfied with small amounts. The right report? An omega-3 for 5 omega-6 (currently, we consume too much of the latter, and not enough of the former).
• Monounsaturated fatty acids (or omega 9 ) are concentrated in olive oil, oilseeds, meat, eggs and fish … Omega 9 enter into the composition of cell membranes, and help increase good cholesterol levels.
• Finally, the saturated fatty acids found in meat, dairy products, butter, sour cream, coconut or palm oil, provide energy to the body (not to mention pleasure. that there is to eat a good toast of buttered bread, or a piece of cheese).
Cholesterol, our friend for life
Of course, it is now known that cholesterol must be divided between “good” (HDL) and “bad” (LDL). But it has long been doomed to whining in its entirety. However, it is essential for good health. It is the precursor of many hormones (progesterone, testosterone, estrogen in particular), it helps our skin to synthesize vitamin D and our liver bile acids (which allow the digestion of lipids). It is also part of the composition of cell membranes. A high HDL level is a sign of good cardiovascular health.
In addition, the one present in our diet (in eggs in particular) has no connection with that present in our body. It is our liver that decides how much cholesterol it will produce and release in our blood: this amount increases with genetic factors, if we are overweight but also when we consume too much saturated fat. And this is why after a long period when we were advised to limit our consumption of eggs, the pressure has now largely subsided!
No need to make toast !
Of course, just because fat isn’t inherently bad doesn’t mean you have to eat in huge amounts. The National Food Safety Agency (ANSES) advises that the share of lipids between 35 to 40% in our total energy intake. On average, a woman over the age of 60 should consume around 1900 kcal per day. About 665 must come from lipids and as 1 g of lipids corresponds to 9 kcal, it would need to absorb around 75 g of lipids per day, giving priority to omega 9 (15 to 20% of total energy intake), and omega 3 (often insufficient in our diet).
If saturated fats remain criticized, studies concerning their possible harmful effects (on cardiovascular health in particular) are very contradictory. In order not to run any risk, “they should represent 15 to 20% of the total fat consumed during the day”, estimates Dr Plumey. As for trans fats, they should be avoided: these fatty acids transformed by industrial processing, which are found in particular in certain ultra-processed foods (ready meals, chocolate bars, etc.), undoubtedly increase the risk of cardiovascular disease. So yes to a good little cream sauce, a pretty shortcrust pastry with butter or a nice vinaigrette but no to ready-made preparations which, anyway, never have the same flavor as homemade!