When people hear the word “FAT,” they cringe. In their minds, they see themselves becoming obese, avoiding a bikini or speedos (showing my 80’s influence) and full of cellulite; despite the massive amount of scientific evidence to the contrary and the popularity of the Mediterranean, Paleo and Ketogenic diets notwithstanding. Still, many questions remain. Some of these include:
Let’s dive into these questions and more about FAT.
Along with carbs and protein, dietary fats are the main sources of energy in our diets. In fact, that’s one of the benefits of fat: it’s a highly concentrated source of energy. With about nine (9) calories per gram, fat is the most energy-dense macronutrient, providing over two times more energy than carbs or protein.
In today’s world, you may be scratching your head as to why that’s a benefit. The fact of the matter is, food hasn’t always been (and still isn’t in some places) so plentiful and available, and the energy density of fat made it a very appealing nutrient evolutionarily. This may be why many of us are so drawn to the taste of fat (more on that in a moment).
Ready for another head-scratching benefit? Fat can be easily stored as body fat, which can provide energy when needed. How the heck is that a good thing? I agree that most reading this probably don’t have a problem with too little body fat. And historically, people have restricted dietary fat intake in an effort to reduce body fat (which hasn’t worked out so well).
Having said that, body fat provides energy when the body requires it (such as during pregnancy, lactation, intense physical activity), it cushions and protects vital organs, and it helps insulate the body.
But dietary fats are much more than a source of energy, they:
Our cell membranes (the walls that separate the inside from the outside of cells) are heavily influenced by the types of fats in our diets. These membranes control the movement of substances in and out of the cells. Both the length and saturation of dietary fats affect the arrangement of the membrane and its fluidity. For example, shorter-chain and unsaturated fats are less stiff and less viscous, making the membranes more flexible.
Meanwhile, the human brain is made up of nearly 60% fat and the essential omega-3 fat DHA is the predominant fatty acid found in the brain. DHA is also heavily concentrated in the retina of the eye and is present in all organs.
Dietary fat is essential for the delivery and absorption of the fat-soluble vitamins A, D, E and K. In a study published in the Journal of Nutrition, researchers from Ohio State University found that when they added avocado or avocado oil to salsa, the absorption of carotenoids (e.g., lycopene, ß-carotene) was up to four times higher than when the salsa was avocado-free. If that’s not enough, when avocado was added to salads, the researchers found that absorption of these potent carotenoids was up to 15 times higher than when the salads were consumed avocado-free.1
As alluded to above, there are certain “essential” fats, which means our bodies need them yet cannot produce them. In other words, we have to GET these fats—namely the omega-6 (LA) and omega-3 (ALA, DHA, and EPA)—from food and/or supplemental sources. For the most part, we get plenty of LA, which you can find in nuts and seeds. In fact, thanks to overconsumption of processed foods, most people consume a potentially unhealthy amount of LA. Most people, however, don’t consume enough omega-3 fats, particularly EPA and DHA, which are most prevalent in fatty fish, seafood and algae.
These Fats are essential, because of the intricate role they play in several vital functions. For example, they’re converted to compounds with hormone-like or pro- or anti-inflammatory properties (such as prostaglandins or leukotrienes). Along those lines, they’re involved in many physiological processes, such as blood clotting, wound healing and inflammation.
Another benefit, dietary fat tends to increase satiety. This means it keeps you feeling full and satisfied (and delaying when you eat next). It’s important, though, to distinguish between satiety and satiation, which refers to the biological processes that are responsible for ending a meal. Along these lines, fat is less satiating than carbs or protein. This makes it easy to overeat dietary fat when you consider the following:
In addition to its functions in human nutrition and physiology, dietary fat plays a key role in the palatability and enjoyment of food. Simply put, fat can make foods and meals more pleasant by enhancing texture, flavor, mouthfeel, and aroma. Think about some of the characteristics of food that people enjoy most: creaminess and smoothness (e.g., cheese), tenderness and moisture (e.g., baked goods), and crispiness and crunchiness (e.g., baked and fried foods).
(There’s a reason why fat—usually poor quality—is added to processed foods and often paired with sugar and salt to maximize enjoyment.)
Generally speaking, the most palatable foods are those that are energy-dense and high in fat content. Evolutionarily, it seems natural that we’d be “wired” to seek these highly rewarding types of foods (which can increase levels of the “feel-good” chemical dopamine). However, in today’s society where most of us are incredibly fortunate to have 24-hour access to a seemingly endless supply of food, our preference toward “rewarding,” energy-dense, high-fat foods may lead to overeating.
As you can see, there’s more to FAT than meets the eye (or the pound). Next week we will cover the types of fats, whether eating fat automatically means you become fat, saturated fats and how much fat you should consume. In the meantime, don’t fear enjoying some good fats; after all, they add flavor!