Myth busted: eating fat doesn't make you fat

Jan 01, 2021
Eating fat doesn't make you fat


Fat doesn’t make you fat.

I repeat: fat doesn’t make you fat. At least not dietary fat of the saturated nature.

This horrific myth dates back to the 1950s and a dude named Ancel Keys. The story is fascinating and if you want the full saga, check out this video (well worth the 2 minutes and 35 seconds).

The gist: Keys incorrectly interpreted data of a clinical study, and linked heart disease to high cholesterol and saturated fat. This set the U.S. on a trajectory of eating only UNSATURATED fats, which are actually worse for you because they use processed, volatile vegetable oils that cause oxidative damage and lead to inflammation and chronic conditions like heart disease, obesity, diabetes and even cancer.

Take action: Stop eating processed unsaturated fats, vegetable oils (in cooking and hidden in our favorite snack foods), and reintroduce healthy saturated fats into our diets (like avocados, nuts, olives, olive oil, meats).

The Full Scoop

Mr. Keys reviewed a 22-country study on the relationship between dietary fat and health. He then hand-picked 7 countries that told the story he wanted to with his research (funded by Big Food): dietary fat makes your cholesterol go up which makes you fat and sick.


The body simply doesn’t work that way. To be clear, neither carbohydrates nor fats on their own cause you to gain weight – it's just that you tend to eat more calories when your diet is focused on carbohydrates over fat. Being in a caloric surplus causes you to gain weight. A carb-heavy diet makes it very easy to be in a caloric surplus.

When you eat carbs (pasta, bread, rice, starchy veggies), they ALL metabolize as sugars in your body. When your bloodstream is flooded from sugar, your pancreas shoots out a fuckton of insulin to go “clean it up” and usher that sugar into your cells for energy.

This normal, natural process breaks down when you repeatedly have too many carbs. (What’s too many? Depends on your body and your goals, but generally, people should keep carbs below 100 grams per day) Your body can become resistant to insulin, meaning that all of that sugar is left floating around in your bloodstream, unable to be pushed into your cells and used for energy… and your liver is forced to convert the sugar into fat and store it. Not to mention, the conversion of sugar to stored fat leaves you feeling hungry again soon after you’ve eaten… making you want to indulge again — specifically in carbs.

Care to guess how many carbs the average American consumes daily? 150-250 grams. Way above what your body can handle or process and stay healthy. I say this not to admonish anyone (I am just as guilty of spontaneous pizza binges or of taking an entire box of mac & cheese to the face). I share it to help debunk a myth that is making our country sick af.

So why eat more dietary fat? Our bodies’ preferred energy source is not carbs (though these can come in handy for quick energy needs such as pre-workout fuel) — it’s fat. Fat keeps us full longer, gives us more energy, reduces inflammation, decreases insulin resistance, and so. much. more.

But it’s gotta be healthy fats. Whole-milk dairy (avoid all low-fat options! I’ll share why in Week 3), nuts, seeds, avocado, olives, oils (but never ever vegetable oils! I’ll share why in Week 2), coconut, dark chocolate, salmon, sardines, pepperoni, butter, high-fat cuts of meat, ALL THE CHARCUTERIE. The best part? Fat is fucking delicious.

So what are the best sources of healthy, saturated fats? According to Dr. Cate Shanahan — the leading authority on metabolic health — here’s a breakdown:


Go Deeper

Fat Fiction: a film that questions decades of diet advice insisting that saturated fats are bad for us. Along the way, we'll reveal the lies we've been told about fats, learn what fats are good, what fats are bad, and what we can do to reclaim our health. Narrated by Dr. Mark Hyman.


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