The concomitant to a low carbohydrate lifestyle is to eat a moderate amount of protein and not shy away from eating animal fat since fat becomes our main energy source when carbs are greatly restricted. Since the late 1950’s most Americans have been taught that fat is something to be avoided. How does a low-carber advocate this type of diet given the historical advice about fat? Answering this becomes especially important since all of us have grown up hearing the dangers of cholesterol and the virtues of eating a high-carb, low fat diet.
Worries about fat also revolved around cholesterol. But over the last few years, the state of scientific research as to the harmfulness of cholesterol has changed, acknowledging that egg yolks can be a part of a healthy diet. However, natural saturated fat is still seen as dangerous and should be limited. This recommendation was based on poorly done and poorly interpreted research. For a thorough discussion of this research see The Big Fat Surprise: Why Butter, Meat and Cheese Belong in a Healthy Diet, by Nina Teicholz.
During our evolution from tree-based primates (i.e., monkeys) to early humanoids, one of the major factors that occurred is the evolution of man as a ground based, not tree based animal. The evolutionary importance this is that a tree-based primate is dependent upon eating tree leaves, i.e., carbohydrates. The evolutionary problem arose that if a primate was to develop a bigger brain than our monkey ancestors, one had to climb down the from the tree and hunt, kill, and then eat the fat of other animals. Fat was the only thing that could give enough calories to fuel the growth of the brain above the size of the carb-fueled primate brain. If we had remained only carbohydrate eating animals, we’d still be in trees with small brains. Eating fat is what allowed us to fuel the development of our larger brains. Even though we’ve moved away from vilifying fat over the last few years, it’s now time to embrace eating fat, not just be okay about it. Eating fat is what allowed us to become humans, fueling the growth in size of our bigger, smarter brains.