Let me introduce myself. My name is Mark Sisson. I’m 63 years young. I live and work in Malibu, California. In a past life I was a professional marathoner and triathlete. Now my life goal is to help 100 million people get healthy. I started this blog in 2006 to empower people to take full responsibility for their own health and enjoyment of life by investigating, discussing, and critically rethinking everything we’ve assumed to be true about health and wellness...Tell Me More
A couple weeks back, I wrote about the top 8 most common reactions you get when people hear you don’t eat grains, and I offered up some concise responses to those reactions. It was well received, so I thought I’d do the same thing for “your high-fat diet.” If you thought having to explain your grain-free diet was tough, explaining a high-fat diet – in particular, a high-animal fat diet – may seem even harder. At least with a grain-free diet, you’re merely removing something that many hold near and dear to their hearts. It’s “healthy” and “delicious,” sure, but at least you’re not adding something that will actively kill you. Fat is that deadly thing, for many people. It’s “fat,” for crying out loud. It’s bad for you, practically a poison. Everyone knows it. I mean, have you seen what fat down the kitchen drain does to your plumbing?
Actually, like the grain-free diet, explaining the high-fat diet is not that hard. I’ll even promise you that there are ways to do it, explanations and answers that don’t make you seem like a crazy person who hates his heart (I make no such promises for those of you with a stick of butter with bite marks and a tub of coconut oil with a greasy spoon beside it on your office desk, however). Now let’s get right to their questions and responses you can use:
“Isn’t all that fat gonna glom onto your arteries?”
That isn’t how it works. Atherosclerosis is caused by oxidized LDL particles penetrating the arterial wall, inciting inflammation, and damaging the arterial tissue. It is not caused by fat mechanistically attaching itself to the surface of the arteries like fat in a kitchen pipe. Also, it’s not like you eat some butter and that butter gets directed straight into your bloodstream. Your blood doesn’t have oil slicks running through it, or congealed droplets of grease gumming up the passageways. You are the product of millions upon millions of years of evolution, and I think our bodies can do better than trying to ape modern plumbing.
Response: “My arteries are not pipes. Fat is not solidifying in my blood like it can in the plumbing. Atherosclerosis is a complex process with dozens of factors beyond what’s in your diet, let alone the fat content.”
“Isn’t all that cholesterol gonna raise your cholesterol?”
If I were a rabbit, sure. When you feed cholesterol to an herbivorous animal, like a rabbit, whose only encounters with dietary cholesterol occur in a lab setting, their blood lipids will increase and they will usually develop atherosclerosis. For many years, the “cholesterol-fed rabbit” was a popular model for studying heart disease and gave rise to the now-popular idea that dietary cholesterol also elevates blood lipids in humans (thus immediately condemning them to a heart attack, naturally). Except it isn’t the case. Save for a select few who are “hyper-responders,” the vast majority of people can eat cholesterol without it affecting their cholesterol levels. And even when dietary cholesterol affects blood lipids, it’s usually an improvement, increasing HDL and the HDL:TC ratio while leaving LDL mostly unchanged. As for where all that blood cholesterol comes from, we make pretty much all the cholesterol in our blood in-house, and dietary cholesterol tends to suppress endogenous cholesterol synthesis. Boy, between “staying local” and “only making as much as we need,” our livers are downright green. I bet our HDL is GMO-free and organic to boot (not so sure about those sneaky LDL particles, though).
Response: “Dietary cholesterol does not affect total blood cholesterol. In fact, when we do eat cholesterol, our bodies make less of it to keep our blood levels in balance.”
“Isn’t all that fat gonna make you fat?”
Fat doesn’t make you fat. While you can technically overeat enough fat calories to accumulate adipose tissue, thus getting fat, this is a difficult feat, for two primary reasons:
Fat is very satiating, especially when paired with low-carb eating. Grass-fed pot roast, ribbed with yellow fat, connective tissue, and ample protein is far more filling than some crusty bread spread with butter. You’ll eat a decent slice of the former and be done, but you could easily polish off half a loaf of the latter with half a stick of butter and still be hungry. It’s difficult to overeat on a high-fat, low-carb diet.
Dietary fat in the presence of large amounts of dietary carbohydrates can make it difficult to access fat for energy, while dietary fat in the presence of low levels of dietary carbohydrates makes it easier to access fat for energy. Couple that with the fact that fat and carbs are easier to overeat together, and you have your explanation. In fact, studies have shown that low-carb, high-fat diets not only reduce weight, they also retain or even increase lean mass. That means it’s fat that’s being lost (rather than the nebulous “weight”), which is what we’re ultimately after.
Response: “No. Eating a high-fat, low-carb diet is the easiest way to inadvertently eat less without sacrificing satiation or satisfaction. It also improves your ability to access stored body fat rather than lean mass, which is helpful for fat loss.”
“But Dean Ornish/my mom/Walter Willet/the AHA/my doctor said saturated fat will give you heart attacks.”
They all may say that, and sound pretty convincing as they say it, but the science says differently. I tend to listen to the science, rather than what I think the science is saying:
That looks pretty clear cut to me.
Response: “The most recent studies have concluded that saturated fat intake likely has no relation to heart disease, contrary to popular opinion.”
“Where do you get your energy?”
I get my energy from fat, both dietary and stored body fat. At 9 calories per gram, fat is the densest source of energy. I’m not sure if you’ve noticed, but humans tend to store it on their bodies. That’s not just for show, you know. We actually store it in our bodies as energy for later, for leaner times, for when food isn’t available. Fat is the ideal energy source for life’s daily activities; walking, working, even going for a hike or a light jog all access the oxidative, or fat-based energy pathway. Carbs only really come into play when you’re doing repeated bouts of intense exercise, like sprint intervals or high-intensity endurance training. But for just about everything else? Fat is king.
Response: “Fat is the body’s preferred and most reliable form of energy, which is why we store excess energy as fat on our bodies. Unless you think we accumulate body fat just to make pants fit tighter.”
“But isn’t fat totally free of nutrients? How do you get your vitamins if you’re eating all that fat?”
The richest source of natural tocotrienols (vitamin E), potent antioxidants, is red palm oil – a fat.
One of the richest sources of choline, a vital micronutrient for liver function, is egg yolk – a fat.
One of the better sources of vitamin K2, an oft-ignored nutrient involved in cancer prevention, arterial health, and bone metabolism, is grass-fed butter – a fat.
The best dietary source of vitamin D, a nutrient most people are deficient in, is cod liver oil – a fat.
See what I mean? Also, even when you’re cooking with a fat that doesn’t contain many vitamins, that fat is still going to improve the bioavailability of the fat-soluble vitamins (like A, D, E, K, K2) in the food you’re cooking.
Response: “Certain fats, like egg yolks, palm oil, extra virgin olive oil, cod liver oil, and grass-fed butter, are some of the most nutritious foods in existence. And without fat in your meals, you often won’t absorb all the nutrients that are present in other foods like leafy greens, since many of them require fat for full absorption.”
“Doesn’t the brain run on carbs, not fat?”
Yes, the brain requires glucose. That is true. However, the brain is more of a gas/diesel hybrid. It can run on both fat and glucose. Ketones, derived from fatty acids, can satisfy the majority of the brain’s energy needs, sparing the need for so much glucose. You’ll still need some glucose, as the brain can’t run purely on ketone bodies, but you won’t need nearly as much. And, best of all, your brain will run more efficiently on a combination of ketones and glucose than on glucose alone.
That improved efficiency means you can actually function without food. Since you have ample brain energy stores on your body (even the lean among us have enough body fat to last for weeks), and a high-fat diet allows you to access that body fat for brain energy, you’ll no longer suffer brain fog just because your afternoon meeting went a little long and you missed lunch. Instead, you’ll enjoy steadier, more even energy in mind and body.
Additionally, your body, through a process know as gluconeogenesis, can make up to 150 grams of glucose a day – more than the brain even needs (roughly 120 grams/day).
Response: “While it’s true that the brain requires some glucose for energy, using fat-derived ketones as well can make the brain run more efficiently and reduce its glucose requirements. On top of that, your body can probably create more glucose than your brain even requires.”
Compared to last week’s grains post, there were fewer entries today, the simple reason being that while grains are hyped beyond belief, people have but a few scant – albeit robustly defended – justifications for fearing dietary fat. The backlash almost always revolves around the visceral fear of “fat.” It’s a scary word, after all, but it shouldn’t be. No one should fear something so vital to life, so crucial for nutrient absorption and hormonal function, and so delicious with roasted vegetables.
Hopefully, these responses will help curb some of that fear.
So, what’d I miss? What else have you heard, and how did you respond? Let me and everyone know in the comments!
Prefer listening to reading? Get an audio recording of this blog post, and subscribe to the Primal Blueprint Podcast on iTunes for instant access to all past, present and future episodes here.