We no longer have to stockpile fat, as in the past, in case hunger or disease lurked. The smart thing to do is not carry extra kilos, choose healthy fats and eat only the necessary ones.
Fats are a fundamental pillar when it comes to establishing the quality of food. In fact, whether the Mediterranean or Japanese dietstype of fatty acids that predominate in them: the oleic acid in olive oil and the omega-3s.
But we don’t always choose fats well. Proof of this is that the current diet in the West has an excess of saturated fats, omega-6 fatty acids and Trans fats.
To say that fats are fattening is a dangerous oversimplification. It is much more practical to know the functions they perform in the body ; what distinguishes them; which ones should be consumed and which ones should be avoided; what amounts a reasonable diet should include; how different fatty acids affect health …
WHAT ARE FATS?
What we usually call fats are triglycerides, where one molecule of glycerol joins three fatty acids. The latter can be of three types:
- Saturated. They do not have double bonds; which makes them very stable and generally solid at room temperature. They predominate in meats, dairy products, eggs, and coconut and palm oils.
- Unsaturated They have two or more double bonds that can react with the oxygen in the air, causing the fat to go rancid. In the vegetable diet, the nuts, seeds and unrefined oils that are extracted from them are its best sources. The omega-3 and omega-6 families are its most important subgroups.
- Monounsaturated They have a single double bond, like oleic acid, the main component of olive oil.
There are other more complex lipids: phospholipids, cholesterol (which our body also makes) and phytosterols, typical of plants.
WHAT ARE THEY NEEDED FOR?
The best known function of fats is energy. They are an excellent “fuel”: they provide 9 kilocalories per gram, compared to 4 kilocalories provided by carbohydrates and proteins, the other two types of nutrients from which the body can obtain energy.
They are also the main energy reserve of the body. For example, the body of a 60 kg woman will have about 15 kg of fat, approximately 25%, which represents a potential energy reserve of 135,000 calories.
- The presence of fat in the diet is also necessary for the intestinal absorption of fat- soluble vitamins (A, D and K).
- Fatty acids are an essential component of cell membranes
- From them, important compounds are formed, such as sex hormones and prostaglandins.
From all this it follows that a diet with a fat deficiency is incompatible with nutritional balance and health.
HOW MUCH FAT IS IT ADVISABLE TO CONSUME?
There is a strong consensus that total fat does not provide more than 35% of total daily energy. This means that, for a person requiring an energy intake of 2,000 calories, the amount of total fat per day does not exceed 78 grams.
Regarding the qualities of this fat, it is recommended that saturated fatty acids are less than 10% of daily calories – less than 22 grams in the previous example – as well as reducing the presence of Tran’s fatty acids as much as possible.
In practice this translates into:
- Give preference to olive oil as a cooking fat.
- Consume moderate amounts of seeds daily (especially flax and chia)
- Consume dried fruits daily (walnuts, almonds, cashews, pistachios …). All this in a framework of moderation and variety.
DO FATS MAKE YOU FAT?
What makes you fat is taking in more calories than you are expending, regardless of the nutrients ingested. However, each gram of fat provides more than twice the calories of carbohydrates and proteins, so their excesses are more likely to induce obesity. On the other hand, ingested fat requires fewer metabolic processes to transform into body fat than carbohydrates and proteins.
WHY IS OLIVE OIL THE BEST FAT?
Olive oil is the star food of the Mediterranean diet and has been revealed as a good friend of cardiovascular health. Its main nutritional characteristic is its high content of oleic acid. Many studies have indicated that thanks to its high contribution of this monounsaturated fatty acid, it lowers LDL or “bad” cholesterol and increases HDL or “good” cholesterol.
It also provides, although in much smaller amounts, the essential fatty acids linoleic and linolenic, and also vitamin E, with antioxidant effects. All these characteristics make it the optimal fat for seasoning and cooking. It can be consumed at all ages, it is easily digested if taken raw and in moderate amounts (advisable), and it gratifies the palate.
The general recommendation for its consumption is 3 to 5 tablespoons daily (30 to 50 ml), ideally between noon and dinner. Among its different forms of presentation, extra virgin olive oil is the one with the most virtues, since it has not been denatured by heat (when cold pressed) nor has the oil from already pressed olives been incorporated after extracting it. By heat and chemical solvents.
IS IT ADVISABLE TO TAKE NUTS?
One of the main nutritional characteristics of nuts is their important contribution of unsaturated fatty acids. The fat content of almonds, hazelnuts, cashews, pine nuts, pistachios and walnuts is mostly unsaturated, that is, it helps control blood triglyceride and cholesterol levels.
Walnuts stand out among them, as their richness in linolenic acid (omega-3 family) has a very beneficial effect on the heart. Nuts are also an extraordinary source of vitamin E, with antioxidant effects, as well as phytosterols.
The recommended intake of nuts is 3 to 7 servings per week (one serving is 30 grams, net weight, without shell) for healthy adults without obesity or overweight. And it is convenient to take them raw and without salt.
WHAT ARE THE KNOWN EFFECTS OF OMEGA-3S?
At the level of cardiovascular health, omega-3 fatty acids (EPA / DHA) improve the lipid profile, reduce blood pressure, increase arterial vasodilation, are antithrombotic and prevent arrhythmias and sudden death.
In addition, its consumption lowers LDL cholesterol, increases HDL and, above all, reduces triglyceridemia (amount of triglycerides in the blood).
In relation to the influence of omega-3s on the brain, there is data that indicates that diets deficient in omega-3s affect its structure and functioning, and learning and behavior.
There are authors who consider it normal that they may be involved in depression and the cognitive decline of aging. They appear to play a role in preventing stress, dementia, and Alzheimer’s, and their benefits have been suggested in dyslexia and schizophrenia.
ARE VEGETABLE FATS ALWAYS HEALTHY?
Not always. Unsaturated fats predominate in most foods of plant origin. However, there are exceptions, such as palm oil (the most consumed in the world) and coconut. When “vegetable oil” is indicated on the label of a product without specifying which one, the probability that it is palm oil (with 50% saturated fat) is very high. It is used in bakery products, pastries, ice cream, cookies…
A study carried out in 2010 showed that the consumption of palm oil in France, even in people who tried not to include it in their diet, amounted to two kilos per person per year, three times more than would be prudent. The palm, on the other hand, is usually cultivated on land reclaimed from the tropical forest.
WHAT IS CURRENTLY BEING STUDIED?
The importance of fats in cardiovascular prevention is one of the best studied nutritional issues and, despite this, it is under continuous review. The reason is the enormous complexity of the issue.
It is true that there is a solid base of recommendations, but as knowledge increases, new questions arise:
- The important change in the consumption of unsaturated fat questions whether what matters is the overall supply of omega-3 fatty acids or whether a balanced diet should maintain an adequate ratio of omega-3 and omega-6.
- It is a fact that today more omega-6 fatty acids are consumed than ever due to their presence in sunflower oils (the richest in them by far), corn and sesame, as well as in margarines and various nuts. And unlike omega-3s, an excess of omega-6 favors inflammatory reactions.
