Figuring out what is good for us to eat and what we should avoid is a controversial and tricky subject. A pretty well-accepted recommendation, though, is the reduction/avoidance of saturated fat, a.k.a. animal fat, and dietary cholesterol intake. We’ve been told for decades that eating saturated fat is going to give us heart disease. Considering heart disease is the #1 killer of Americans, it’s no surprise that we’re all ears and willing to take that advice.
The low-fat recommendation stems from research done by physiologist Ancel Keys in the 1960s, where he studied the effects of dietary fat on the body at University of Minnesota. He made the hypothesis that saturated fat, which is found in animal products like butter, cheese, and red meat, as well as some oils like coconut, is linked to higher cholesterol and increased risk of cardiovascular disease. His hypothesis was based on a poorly conducted study looking at the habits of 7 different countries around the world that showed a correlation between the factors in some populations, but paid no tribute to other contributors like refined sugar intake or activity levels. Keys also ignored that several populations who still ate traditional food consumed plenty of saturated fat and had virtually no health problems. Anyhow, he went on with his study.
To test the effects of saturated fat, Keys fed margarine to lab rats and watched their cholesterol levels go up. The research was publicized to make people believe the rats were fed butter, which is mostly made up of saturated fat. On the contrary, margarine is largely trans fat, a toxic substance made from over-processing plant oils. Another key objective of delivering this research to the public was creating the image of arteries being clogged by animal fat. We all know this phrase, of course. The truth is, that’s absolutely nothing like how metabolism really works. Dietary fat does not end up in your arteries in its original form. Would we believe that when you eat spinach, little pieces of it get lodged in your lungs? Of course not. There is a slew of digestive and metabolic steps to digest the fat and all other nutrients. Artery plaques are not made of fat molecules. Keys’ research caught on, though, and by the 1970s, the American Heart Association was recommending Americans reduce their fat intake from 45% of daily calories to 30%, with a maximum of 10% of daily calories coming from saturated fat. And America listened. Consumption of animal fat continued to drop for decades. So if what our health agencies tell us is true, heart disease, high cholesterol, and obesity should have become less common. But that didn’t happen. Heart disease currently costs Americans almost $300 BILLION per year. Other key factors need to be considered, but it’s important to understand why saturated fat is not the enemy.
Trans and unsaturated fats deserve some attention in this conversation, but I want to describe how our body uses the saturated kind:
- Every hormone in our body as well as the walls of our cells are made directly from cholesterol and lipids (fats). Taking those components out of the food we eat denies our bodies of great resources for building strong, healthy cells and signaling hormones.
- Saturated fat and cholesterol derivatives make up the protective tissue of the nervous system and brain.
- Fats contain fatty acids that help lower your “bad” cholesterol and raise the “good” cholesterol, which is literally the direct opposite of what we’ve been told since the fat-fear research came out.
- If you’ve ever heard the value of vitamins A, D, E, or K, I hope you also know that they can only be used by your body if there is fat available. These are called fat-soluble vitamins and they’re crucial for a variety of reasons. Milk is marketed to be high in A and D, particularly, but if you buy low-fat milk, those vitamins have been stripped away along with the naturally-occurring fat. The vitamins listed in low-fat milk on the nutrition label have been synthetically made and added, but you won’t even absorb them efficiently since they aren’t coming with the fat they were packaged with in the original product.
- Fat consumption triggers the release of satiety molecules in our bodies that tell our brains we got enough nutrients, and it’s OK to stop eating because they’re such a potent energy source.
If the science and physiology just doesn’t resonate with you, simply consider what our ancestors have been eating for hundreds of years. They cooked with lard, and ate butter, beef and eggs long before heart disease ever became an issue. I encourage you to do some research of your own about how the perception of saturated fat is finally changing among some medical professionals if you’re not convinced yet. There are some really great books that extensively describe the history of fat and cholesterol research and the ways in which they have benefited human evolution. Eat the Yolks by Liz Wolfe is perfect for someone who is not very acquainted with science and medical terminology. If you’re someone who is comfortable reading about scientific research and chemistry, Deep Nutrition by Cate Shanahan lays the foundation for why we need fats and traditional food.