Dietary fat has been both demonized and praised in the health world. High fat diets, low fat diets, they’re good, they’re bad, fat in general is bad, blah blah.
The truth is that it’s not black and white when it comes to fat. There are different types of dietary fat, and they actually have different effects on health. Some better and some worse..
In this article, we’ll cover:
The different types of dietary fat
The effects they have on the body
Fats and disease – cardiovascular disease, diabetes, Alzheimer’s
How much to have
Omega-3s
Dietary Sources
Lezzz goooo
TYPES OF FAT
There are four main types of dietary fat:
Saturated fat
Polyunsaturated fat (PUFA)
Monounsaturated fat (MUFA)
Trans fats
SATURATED FAT
Saturated fat is the primary fat found in animal products, as well as coconut and palm oils. It also exists in virtually every food, including broccoli, just in trace amounts.
Saturated fat is also a type of fat that our body makes, and therefore, isn’t an essential fat that we would need to get from food.
Saturated fat also tends to be solid at room temperature.
POLYUNSATURATED & MONOUNSATURATED FATS
These types of fats are primarily found in plants. Monounsaturated fats (MUFAs) are also produced by the body, while polyunsaturated fats (PUFAs) are not, and are therefore essential fats that we need to get from food.
TRANS FATS
Trans fats exist naturally in small amounts in some animal products, but are mostly found in partially-hydrogenated oils when liquid oil is transformed into more of a solid fat. These are basically terrible…
EFFECTS ON THE BODY
Research, clinical trials, and various meta-analyses have shown just how each of these fats affect the body, let’s discuss!
SATURATED FAT
Saturated fat, when eaten in higher amounts, has been shown to increase LDL (“bad”) cholesterol levels in the blood that can drive plaque buildup in the arteries (due to a lipoprotein called ApoB), lead to insulin resistance, and even plaque buildup in the brain.
PUFAs & MUFAs
Poly and monounsaturated fats have actually been shown to decrease LDL cholesterol levels, and provide benefits for the heart and brain.
TRANS FATS
Trans fats have been shown to greatly increase LDL cholesterol levels, lower HDL (“good”) cholesterol levels, and drive plaque buildup in the arteries. Trans fats are also considered to be not only the most unhealthy type of fat, but also one of the worst things you could put in your body.
FATS & DISEASE
Certain types of fat have been associated with increased risk of diseases such as cardiovascular disease, type 2 diabetes, and even Alzheimer’s dementia. Other types, however, have been associated with decreased risk of these diseases. Let’s dive into why this might be..
FATS AND CARDIOVASCULAR DISEASE
In terms of cardiovascular disease risk, the two main players here would be trans and saturated fats. How do they contribute? As stated before, they both have been shown to increase LDL cholesterol levels, which can lead to plaque buildup in the arteries. Let’s unpack this more…
Trans fats across the board are unhealthy, but there’s a little more to saturated fats…
There are actually different types of saturated fat that can sometimes have different effects on cholesterol, depending on the source. The type found in dairy, for example, hasn’t been shown to increase LDL cholesterol levels much, but rather, has a more neutral effect.
Sidenote: dairy is a concern for numerous other reasons, so it’s not off the hook.
However, the saturated fat found in red meat, processed meat, butter, ghee, lard, etc, has been shown to increase LDL cholesterol levels in the blood, among other things. But why?
From what I’ve learned, one of the tasks of our liver is to remove LDL cholesterol from the blood to help control levels. The liver has LDL receptors that are responsible for this. It’s been shown that saturated fat from the sources mentioned above actually down regulate these LDL receptors, which in turn, leads to less cholesterol being filtered from the blood, which we don’t want.
Essentially, the more saturated fat someone eats from the various animal sources, as well as coconut and palm oils, the greater the risk for cardiovascular disease. Now the crazy thing is, this is not the same for PUFAs and MUFAs.
Not only do these plant-based fats not raise cholesterol levels, but PUFAs in particular have been shown to up-regulate LDL receptors in the liver, resulting in lower cholesterol levels. The exact opposite effect of saturated fats. Let me rephrase..
Polyunsaturated fats have the exact opposite effect on cholesterol levels and cardiovascular disease risk than saturated fats. Right on.
FATS, INSULIN RESISTANCE, AND TYPE 2 DIABETES
To this day, carbs still get thrown under the bus when it comes to type 2 diabetes. But the truth is, the main cause has more to do with fat. I bet you didn’t see that coming.
Type 2 diabetes is when a person’s insulin – the hormone that transports glucose, or blood sugar, into cells to be used for energy – is still being produced by the pancreas, but it no longer works, and can’t properly transport glucose into cells. This causes the glucose to remain in the blood, resulting in high blood sugar. Overtime, high blood sugar can cause damage to nerves and blood vessels all over the body.
But why does this happen? Why can’t insulin properly transport glucose into muscle and liver cells? This is where fat comes in…
It’s been shown that eating a higher % of total calories from saturated fat (more than 10% of total calories) can lead to fat buildup in the muscle and liver cells, called intramyocellular lipids, which blocks the glucose from getting in. A good analogy for this is imagining a lock being jammed up with gum.
So, saturated fat technically causes type 2 diabetes, not carbs. Having high blood sugar is a mere symptom of insulin resistance, yet it’s the main thing that tends to get focused on.
Not surprisingly, PUFAs and MUFAs have not been shown to cause insulin resistance. And swapping saturated fats for PUFAs and MUFAs has been shown to be more protective against cardiovascular disease and insulin resistance. This could have to do with the more positive effects these fats have on the liver and cardiovascular system.
FATS & ALZHEIMER’S DEMENTIA
What used to be thought of as just an “old person’s disease” is now being looked at more as a lifestyle disease. Yes, this includes food.
Researchers in Chicago in the 90s were studying the brains of dead patients who suffered from Alzheimer’s. They discovered these plaques all throughout the brain, eventually called amyloid plaques.
More research on these plaques showed that they actually originate from having higher levels of… yep, saturated fat in the diet.
It’s now been established that chronically eating higher amounts of saturated fat can lead to amyloid plaque buildup in the brain that disrupts brain function and leads to Alzheimer’s dementia. This has also recently been called type 3 diabetes.
The thing is, just like the rest of our body, our brains love glucose. And it loves to burn it for energy. Fat that builds up where it shouldn’t blunts the normal process of using glucose. So, this process that happens in the brain is very similar to what happens during type 2 diabetes, hence this being labeled type 3.
But as stated earlier, PUFAs and MUFAs actually have benefits for the heart and brain. And have not been shown to lead to any of the mentioned diseases.
HOW MUCH FAT SHOULD YOU EAT?
How much fat someone should eat is individual. Some people can eat more, some prefer less. One simple rule is to aim for roughly 30% of total calories to come from fat, with 10% or less of that coming from saturated fat.
Another rule would be to aim for at least 30g – 60g of fat per day (with up to 20g coming from saturated) in order to at least support proper hormone function and absorption of fat-soluble vitamins.
Keep in mind that fat also is higher in calories than carbohydrates or protein. Here’s the breakdown of that:
Fat: around 9 calories per gram
Carbs: around 4 calories per gram
Protein: around 4 calories per gram
So for anyone looking to lose weight or avoid unwanted weight gain, keep an eye on fat intake. The calories in things like olive oil or peanut butter can add up pretty quick without you realizing!
OMEGA-3: EPA & DHA
One of the most common types of PUFAs are omega-3 fatty acids. There are 3 forms: ALA, EPA, and DHA.
ALA is high in foods such as flaxseed, chia seed, and walnuts, while EPA and DHA are higher in fatty fish. Here’s the thing…
Most people think of fish and fish oil supplements to be the key when it comes to getting their essential omega-3s. This is mostly because of marketing and business. The fish and seafood industries, just like the rest of animal agriculture, are powerful when it comes to this.
The reality is, fish actually get their omega-3s from algae. That’s right, one of the main benefits of eating fish actually stems from plants.
Fish are sentient and intelligent creatures that can suffer and feel pain just like all other animals, and humans. And fish farming, same as all animal agriculture, is atrocious on the environment.
And the best part is, nowadays, algae-based omega-3 EPA & DHA supplements are widely available. A much better alternative to eating fish or taking a fish oil supplement.
SOURCES OF FAT
When looking to promote better health outcomes and lower risk of various diseases, choices matter. Here’s a quick list of some food sources of each fat:
SATURATED FAT (limit or avoid)
- Red meat: steak, beef, pork
- Processed meat: bacon, sausage, ham, deli meats
- Butter
- Ghee
- Coconut oil
- Palm oil
POLYUNSATURATED FAT (PUFA) (fats to focus on)
- Tofu
- Soy milk
- Soy beans
- Walnuts
- Flax seeds
- Canola oil
- Sunflower oil
MONOUNSATURATED FAT (MUFA) (also fats to focus on)
- Peanuts
- Olive oil
- Avocado
- Canola oil
- Peanut butter
- Peanut oil
- Pumpkin seeds
TRANS FAT (worst of the worst)
- Partially-hydrogenated oils
- Shortening
- Baked goods
- Fried foods
- Margarine
Choose wisely. And thanks for reading!
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