Know Your Fats by Mary Enig

Know Your Fats as the title states is the complete primer for understanding the nutrition of fats, oils and cholesterol. The book took a few reads for me to fully absorb as the book starts out with the author describing in detail the chemical composition of each fat, technically lipids. Essentially all lipids are formed by molecules called triglycerides (TG) which is glycerol molecule with three fatty acids attached. Lipids, compared to the other sources of energy, protein and carbohydrate, are extremely energy dense at nine kilocalories per gram. This is true of all fats, whether we’re talking about those so bedeviled saturates or those so praised omega threes; all fat has nine kcal per gram.   Both protein and carbohydrate, by contrast, have four kilocalories per gram. This energy density makes fat extremely easy to store for energy to be used by the body later. Stored fat isn’t very metabolically taxing for the body as the other energy sources making fat beneficial for later use, -ahem- in the fasted state.

The book goes on to describe all of the different types of fats and how they interact with the human body. Interesting things I learned is the the human body stores is that palmitic acid, a 16 carbon chain saturate, is the human body’s go to source for storing energy as it is the first fat that is created from fatty acid synthesis. As well, the human body creates quite a bit of oleic acid, the same 18 carbon mono-unsaturated fatty acid found in Olive Oil. Indeed, one thing the human body does exceedingly well is produce its own fat, both of the saturated and MUFA varieties. The human body is constantly producing different types of fat for different purposes. The only two lipids the human body can’t create are linoleic acid, popularly known as omega 6′s, and alpha-linoleic acid, popularly known as omega 3′s. Both Omega 3′s and Omega 6′s are referred to as essential fatty acids. They are the only fatty acids that cannot be produced by the human body and they both must therefore come from the diet.

Saturates aren’t the Culprit; synthetic trans-fats are. Dr. Enig seems to have written this book as response to all the hysteria surrounding fats, and specifically saturated fats. The author does a good job of laying the case for why the various types of fats are useful for the body. Steric acid, a saturated acid commonly found in beef, pork dairy and dark chocolate, is a well known precursor to testosterone, for example. Dr. Enig also has a lot of praise for the tropical oils, specifically coconut oil. Coconut oil, for the most part, is purely saturated fats with a little more than half of the oil being made up of medium chain triglycerides (MCTs) which are saturates with eight to twelve carbon chains. Interesting thing to note is that human mother’s milk is mostly made up of MCTs which is why you’ll find coconut oil in many baby formulas. MCTs have many benefits for health as well that work in the prevention of certain diseases. As well, I would just note that coconut oil is extremely useful in the kitchen with its high smoke point and the stuff lasts forever.

The actual danger lurking in our food supply are the hydrogenated vegetable oils, often referred to as trans fats. Oftentimes these fats and oils are rancid, or heavily oxidized. Consuming oxidized fats will wreak havoc inside the body leading to many disease states such as cancer and heart disease. It’s best to do your best to avoid these fats, but the problem is that they are everywhere. The best way to avoid or limit your intake of transfats, as stated before, is just to avoid eating at restaurants that use vegetable oils and any pre-packaged foods. 

Dietary Fat Recommendations

The book ends with a simple recommendation which is to use a mixture of natural healthy fats in moderation. But what is moderation? Dr. Enig makes the point that fat historically has taken up about 30% of the kilocalories consumed in the American diet. If you’re looking for a hard and fast number, I like Alan Aragon‘s idea. Average out your daily fat intake to be about one half of your body weight in pounds. So a 120lb female should consume an average of 60g of fat per day or a 160lb male should consume roughly 80g of fat per day.

Summing up

This book is a no-nonsense primer on everything you wanted to know about fats. While the tone is a bit confrontational at times, it is understandable due to the anti-fat hysteria of the past few decades. Truth be told, there is absolutely nothing wrong with any type of fat even of the saturated variety, so long as you consume them within your caloric tolerance. About the only fats to avoid are the man-made synthetic transfats that have made their way throughout the food supply. Dietary fat should should take about roughly 30% of all consumed calories, or 0.5g per body weight in pounds. While saturated fats are okay to consume, strive to consume a variety of fats. Remember also that the human body does an incredibly great job of producing its own saturated fat as well as mono-unsaturated fat. The only fats that are technically necessary are omega 6s and omega 3s. So eat plenty of meat and fish, help yourself to some olive oil as a topping for the salad and don’t feel like you need to be bashful with the butter.

You can Purchases Know Your Fats by Dr. Enig here.