"Eating fat makes you fat". You've heard this before, and it's a myth that refuses to die. This notion appeared in the mid-1970's and is now so deeply entrenched in our western cultures, that fat-phobia when it comes to food is now commonplace.
From a basic calory standpoint this appears to make sense. At 9 calories per gram, versus 4 in carbohydrates and proteins, you could think that eating more fat would lead to more weight because of higher calorie load. But that's not how the body works. A calorie is not just a calorie, it's what our body does whith the calories that matters most, and this use is dependant on the macro-nutritient (so lipid, protein or carbohydrate).
A very simplistic way of explaining how you should look at calories would be to say that it is a measure of how much energy you can get out of each gram. So byt that logic gram for gram, fat is twice as good. I'll adress the confusion around calories in another article so let's leave it aside for a now and talk about the fat.
So what does our body does whith the fat we eat? Does it just store it in our thighs and belly? Well fat actually many vital uses in the body.
First of all, every single cell membrane is made with fat. Yep, every single cell, not just fat cells. I think that qualifies as a vital function.
Fat is necessary for proper digesting and assimilating fat-soluble vitamins: A, D, E and K. The foods that conaint these vitamins are convenient also fat sources. So the fat and egg yolk allows you to assimilate its vitamins A & D it contains so much of.
Fats are required for the adequate use of protein. So all the egg whites in the world won’t help you out if you’re not eating them with the fats in the yolk to access that protein properly.
Fats are essential in managing inflammation in your body, by being used in the anti-inflammatory process. There are fats that contribute to inflammation, those in seed & vegetable oils, but this actually due to the processing require to extract them, and not the actual fats themselves (seeds and vegetables are fine when untampered).
But fats are most known as a source of energy, and is very efficient one at that, consistent and smooth burning like a log in a fire as opposed to kindling. they also slow food absorption, which helps with energy regulation as well.
Ok, so fats are important, and absolutely vital, and should not be avoided in any way. But because we label "fat" both exogenous (dietary and endogenous lipids, we tend to think they are one and the same, when there's more to it.
So if dietary fat isn't what you're storing in you thighs, what is it? I'll spare you the suspense: it's sugar. But let me explain.
Here’s something really important to know about fat: it does not trigger the hormonal dance that creates fat storage the way that sugar and other starchy carbohydrates do. When you eat something sweet, your blood sugar levels increase too quickly, and your pancreas secretes the hormone insulin to take the excess sugar out of your blood. Insulin is a fat storage hormone. It stores that extra sugar first as glycogen, and then as triglycerides (fat) once glycogen stores are full.
When insulin is activated, its partner hormone, glucagon, can’t operate. Glucagon’s job is to mobilize stored sugar back into the blood for energy use. These two hormones are constantly in a dance with each other and cannot be present in the blood at the same time. So either your body is in an energy-burning/mobilizing state (glucagon) or your body is in an energy storage state (insulin).
Sugar mobilizes insulin; fat does not. It’s that simple. In fact, the fat in a sweet treat will actually help to slow down that sugar spike, and thus reduce the insulin surge, mitigating some of the ill-effects of the sweet. This is why the whole fat-free dessert thing is such a bad idea. Not only are you mobilizing a ton of insulin, you’re also removing the one thing in there that could slow that process down.
Another piece to this puzzle is satiation. The digestion of fats triggers your satiation mechanism. This is why low-fat diets are doomed to fail and such an exercise in fierce willpower. Your body is never satisfied without fat, despite the number of calories (one more reason why calories aren’t the be all and end all).
It’s quite the opposite with sugar or foods converting to sugar quickly in the blood (starchy carbs like bread, pastas, cereal, potatoes, etc…). These foods inspire overeating and binging in part because they don’t satiate and in part because of the insulin reaction we explained above. After insulin has done its job of storing that extra sugar as fat, guess what happens? Your blood sugar takes a big hit and you now are in a low-blood sugar space. What do you crave now? You got it… more sugar.
This means: eating fat makes you fuller sooner and longer. Eating sugar leads to a sugar crash which makes you hungrier sooner and in a position to crave more sugar. A vicious cycle indeed. Now, are all fats created equal? Not by any stretch. In fact, industrially processed oils and rancid fats are ubiquitous in the diet and extremely harmful to both our health and our waistlines. But real, unadulterated fat from quality sources used appropriately is a key component of any healthy diet.
Here’s the bottom line: Eating fat doesn’t make you fat. Eating sugar makes you fat.