The Nutritional Boogeyman of the 1980s: Dietary Fat
Why fat got a bad rap, three types of dietary fat, and how to eat fat for a healthy brain and body.
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Evil Fat: Why did fat get a bad rap?
Fat gained a bad reputation in the 1980s for two reasons:
It has a high caloric content (9 calories per gram) compared to the other macronutrients (carbs and protein only have 4 calories per gram).
A certain type of fat can raise LDL cholesterol, thus increasing risk for cardiovascular disease.
But the reality is that fat is essential to a healthy diet.
We just need to consume it in a way that doesn’t leave us in a long-term caloric surplus, negatively impact our metabolic health, or increase our risk of cardiovascular disease.
Types of Fat: What is fat?
Fats are unique in that they are a hybrid macronutrient—they are both a fuel source and building blocks.
Like carbs, fats are a fuel source except they act like slow-burning logs, our preferred fuel for long-duration endurance, whereas carbs act like gasoline being poured on a fire, powering our body for short but intense bursts of energy such as sprints.
Like amino acids (protein), fat acts as the building blocks for many hormones (in the form of cholesterol) and cell membranes.
There are three main types of fat:
Saturated fatty acids (SFA)
Monounsaturated fatty acids (MUFA)
Polyunsaturated fatty acids (PUFA)
Polyunsaturated fats can be further broken down into Omega-3 and Omega-6 fatty acids.
Omega-3s, which are often sold in supplement form as “fish oils,” can come from marine (EPA and DHA from salmon and other fatty seafood) or non-marine (ALA from nuts and flaxseed) sources.
There are also trans fats, but due to their role in contributing to cardiovascular disease, they have been banned by the FDA and largely removed from our diet.
Here’s an easy way to differentiate between types of fat:
Saturated fats (SFA) tend to be solid at room temperature
Unsaturated fats (MUFA and PUFA) tend to be liquid at room temperature
However, no food consists of only one type of fat.
All foods that contain fat contain all three types of fat—SFA, MUFA, and PUFA—in varying quantities.
For example, olive and safflower oil are very close to pure MUFA but still contain PUFA and SFA in smaller quantities. Similarly, coconut and palm oil are nearly pure SFA but still contain both MUFA and PUFA.
That means we can tweak the ratios of how much of each type of fat we consume based on the foods we eat, but cannot eliminate certain types of fat entirely.
Eating Fat: What fat should we eat and how much?
In Theory
Ensuring we eat the right mix of fats is important for our brain health—much of our brain is made up of fatty acids—and metabolic health.
Dietary fat, especially when paired with protein, also makes us feel more satiated than carbs which can help us to prevent overeating.
In his bestselling book Outlive, Dr. Peter Attia recommends total fat consumption be broken down into targets:
50-55% MUFA
15-20% SFA
PUFA to fill the gap (25-35%)
To support brain and cardiovascular health, Attia also recommends boosting intake of the Omega-3 fatty acids EPA and DHA with marine fat sources such as salmon or through supplementation.
If you really want to geek out, there is a blood test you can do to measure the amount of EPA and DHA in the membranes of your red blood cells. For most of his patients, Attia aims for 8-12% and adjusts Omega-3 intake as needed to reach that goal.
But unless you eat a lot of fatty fish, even without a blood test, most people would probably benefit from supplementing EPA and DHA (Omega-3s or “fish oils”) in capsule or oil form.
In Practice
Since most people would rather drive stakes through their eyes than track fat intake and titrate EPA and DHA consumption, here are a few practical guidelines for healthy fat consumption.
Eat more olive oil, avocados, and nuts.
Reduce omega-6-rich corn, soybean, and sunflower oils.
Eat less butter and lard and things that contain butter and lard.
Increase omega-3 marine PUFA from sources like salmon and anchovies or through high-quality fish oil supplements.
Individualizing Fat Intake
At the highest level, MUFA seems to be the “healthiest” fat followed by PUFA, with SFA seen as the “least healthy.” (Hence the recommended % breakdown above.)
But these are just broad guidelines for the general population.
At the individual level, you must take greater responsibility for how fat consumption affects your health, particularly your LDL cholesterol (LDL-C) and apoB levels—key risk factors for cardiovascular disease.
By watching what you eat and having regular lipid blood panels that measure your LDL-C and apoB concentrations, among other markers, you can better understand how certain foods impact your overall lipid and inflammation response.
Two people eating the same amount of saturated fat can have drastically different responses in their apoB concentrations, and thus entirely different risk levels for cardiovascular disease.
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Jack Dixon
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