Katherine Baker

Everything you need to know about dietary fats.

Hello friends! Today I’m going to be adding to my “macronutrient” category of info, by telling you what you need to know about dietary fats and nutrition. Dietary fat is one of the three essential macronutrients, along with protein (which I wrote all about here), and carbohydrates. There is constant confusion about what’s good and bad in terms of fat, so I thought I’d break down the current state of science for all my lovely readers.

Side note: welcome to my new site! I will slowly be updating all of the previous posts to look more polished with printable recipe cards, and will be working on a more user-friendly recipe tab page, and pumping out a lot more nutrition and environmental health science-based content! Whoo! I appreciate your patience as I get the page to exactly where I want it aesthetic/interface-wise, as I’m a one-woman show without the budget for a web-designer over here :-).

What even is “Fat?”

Now back to dietary fats! As I mentioned above, fats are one of three macronutrients (along with protein and carbohydrate). Macronutrients are what make up the human diet and give the body energy, meaning they have calories. This is how they differ from micronutrients (like vitamins and minerals), which are also essential, but do not contain energy (calories).

As I mention in this article, fats contain 9 calories per gram. This makes them the most calorically dense macronutrient, as both protein and carbohydrates contain 4 calories per gram.

Fats, also known as “lipids” in much of the science world, are comprised of carbon, hydrogen, and oxygen atoms, with both hydrophilic (water-loving) and a hydrophobic (water adverse) ends.

Lipids are important structural molecules in the body, and serve a variety of functions, including making up the phospholipid bilayer that surrounds every cell. Lipids are also important for making hormones and steroids, which serve important cell-to-cell communication functions. They also serve a role in the growth and development of tissues.

How Much Fat Should I Eat?

Dietary fats were once demonized as “low fat” diets took over in the 80s and 90s. It seems these days, fats are making a comeback. Some people even take it to the extreme with the “keto” trend (which I will devote an entire separate post to talking about), and consume lots of fat and protein and minimal carbohydrates.

Yet, fat is still often feared by many dieters hoping to loose weight, and many products still market their “low fat” content as an asset. So it is often, understandably confusing, for most people to know much fat they should eat.

According to the Institute of Medicine, fat should make up 20-35% of total caloric intake for healthy adults, meaning roughly 1/5-1/3 of the calories you take in should come from fat.

Obviously, different individuals in different stages of life with varying medical conditions may have slightly different needs. But for most, 20-35% of dietary intake from fat is considered optimal.

So What Fats Are Not Good For Human Health?

I don’t often make statements about thing being “bad” for you (as I believe deeming foods ‘good’ and ‘bad’ oversimplifies things much of the time), but I can tell you this: there is substantial evidence that trans fatty acids (aka ‘trans fat’) raises LDL cholesterol and is detrimental to heart health, and considered a risk factor for cardiovascular diseases and stroke.

There is also speculation that trans fat impacts the metabolic system and may be linked to insulin resistance and type II diabetes. The lack of certainty due to these later two points may be due to differences in study designs and the inherent difficulty of studying and measuring the human diet.

But one thing seems quite certain: trans fats are linked to coronary heart disease. And they should be avoided, whenever possible.

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