I make it a point to not outwardly judge anyone’s dietary preferences, and for the most part it’s easy for me – keto, vegan, gluten free, whatever. It’s your choice and if you feel good, then godspeed my friend! But there is one diet preference that makes me bite my tongue every. single. time. and that’s low fat diets. If you’re still a low fat advocate, allow me to attempt to change your mind on the whole “low fat = healthy” concept.
The beginning of the low fat craze
Let’s start at the beginning: where did the idea of a low fat diet come from? and how did it gain such popularity? The government officially started recommending a diet lower in fat and higher in grains back in the 80’s, but this concept was being subtly enforced by the medical community for decades before that.
As early as the 1950’s, there were studies trying to prove the fat, specifically saturated fat, was causing increased cholesterol and heart disease. Ancel Keys was the father of the Diet-Heart Hypothesis, and spent decades leading and documenting studies that confirmed that this was true, and that saturated fat was bad for human health.
The problem with these studies, is that they were extremely limited, and the data was creatively manipulated to confirm his theories. Regardless of the flawed research, Keys was a smooth talker and managed to convince most of his peers that his studies proved that increased fat consumption caused an increase in heart disease. The few who disagreed with him were pushed out of the medical community, so their voices were small and ignored.
Over the decades, Keys’ influence grew, and led us into the fat-phobic 90’s. Big food companies were buying in because they wanted to sell their products. They found ways to remove saturated fats from products, and started labeling packages with buzzwords like “low fat” and “heart healthy”. The problem here is that most of these “foods” contain higher amounts of sugars and/or trans fats to make up for the lack of saturated fat (and flavor!). Spoiler alert for a future post: trans fats, sugars, and processed foods all contribute towards inflammation in the body.
Almost 30 years later, and there has been a lot of great progress towards education around nutrition, and the important role fat plays in our health. Thanks in part to the internet making research readily available, and to the people who were brave enough to question the status quo and look for real answers instead of trusting what became common “knowledge” after so many years of hearing that fat is bad for us.
What’s the truth about dietary fat?
The next question I’m sure you have is, “but doesn’t eating fat make me fat?” and the short answer is: no. A majority of the fat stored on your body comes from when your body has too much glucose (sugar) in the blood and needs to put it somewhere. Glucose is a quick-burning energy source, so your body doesn’t want to waste it! Instead, your body stores that excess glucose for later use in muscles and adipose tissue. The problem is when we never use that stored energy and instead continue to add to it.
What exactly does fat do then? Great question. Fats found in whole, nutrient dense foods are usually a combination of saturated, monounsaturated, and polyunsaturated, and these are the 3 types that we want in our diet. I won’t get too science-y here, but just know that the different types of fat are classified based on how long or short their chains of carbon atoms are, and if the chains are fully “saturated” with hydrogen atoms, or if there are some open gaps in the chain.
Saturated and unsaturated fats are an important part of our diet because they help us absorb vitamins A,D,E, and K, regulate our digestion, provide slow-burning energy (like throwing a log onto a fire instead of kindling), and they are a crucial to building cell membranes and hormones. They also create a protective lining around our organs and cells.
Now imagine, if you’re on a low fat diet, you’re missing out on important vitamins, no matter how much you try to supplement for them; you’re relying on energy from glucose (aka the kindling) so you’re probably hungrier between meals; and your cells are suffering because they probably have week or damaged lipid barriers. One final thing to point out: did you know your brain is made of approximately 60% fat? So you’re probably feeling more sluggish/irritable and maybe having trouble with your memory on that low fat diet as well.
Say “no” to trans fats
There’s one type of fat that is absolutely something that we should avoid at all costs, and that is trans fats. Trans fats are man-made fats that became popular during WWII because the real butter and fat was rationed to troops. Big food companies decided to market a butter substitute, margarine, as a healthy alternative. Margarine is a whole topic on it’s own, so I won’t get too preachy here, but the basic reason why trans fats do not belong in our bodies is because they are so over-processed that they become broken and rancid on a cellular level. It’s a very simple “you are what you eat” scenario, where if you’re consuming rancid, broken foods, your cells will be come rancid and broken as well.
So, throw our your fat free yogurt and invest in avocado stocks, right? Well, sort of. Every person is unique, and we all require different levels of fat to be our best selves. The amount required can vary from >30% of your daily calories to just a tablespoon or so at each meal, and everywhere in between. Try adjusting the amount of healthy fats in your diet by incorporating grass fed butter & dairy, properly raised meat (factory farm meat is another post entirely), olives and cold pressed olive oil, avocado and cold pressed avocado oil, coconut, and nuts. Take note of how you feel with different amounts – are you hungry within a few hours or can you get through 4+ hours without needing a snack? How’s your mental clarity? Once you find a balance that makes you feel good, you’ve found your personal fat needs! Just remember to say NO to trans fats!
Curious about the Diet-Heart Hypothesis and Ancel Keys influence? I got my info from The Big Fat Surprise: Why Butter, Meat and Cheese Belong in a Healthy Diet by Nina Teicholz, and highly recommend you pick it up for further reading.