Most of what the majority of the population knows about nutrition is wrong. We have been beaten over the head pretty much since childhood that fats make us fat and cause all sorts of problems. Over the last few years there has been a growing body of evidence that the opposite seems to be true. In fact the evidence goes back much longer. It has even come to light that studies depicting fat as problematic were sponsored by the sugar industry, which was essentially bribing Harvard University researchers to cherry-pick results. We believe a short review on the topic our diets would be helpful to a lot of people. We will talk about the proportions of macro-nutrients (fat, carbohydrates and protein) in our food, and also how often we should eat.
Think about how our ancestors used to eat back when homo sapiens was leading a hunter-gatherer lifestyle. For the hunter part, a group of hunters would set out to kill a prey. This would provide the tribe for a certain amount of meat. What would follow is a feast of sorts, where everyone would get a copious quantity of meat. Keep in mind that in the days before the ability to make fire was developed, meat was eaten raw, which means the fat content was much higher as the fat would not melt during cooking. Then once the meat was eaten, the hunters would then head out to find and kill another prey. They did not know when the next kill would happen, and might go without food for extended periods of time. One of the benefits of fasting is the triggering of autophagy, the body’s cleanup and recycling mechanism. The a look at our Autophagy Stack so you can trigger it faster.
Foraging for plant-based food was likely done on a fairly constant basis. Consider that fruit and vegetables back then were nothing like the heavily cross-bred specimens optimized for yield we have today. And for a tribe of any reasonable size, they would be able to clean out the locally available supply very quickly and need to move on to other locations to find more to eat. Another detail that most people do not realize is that we did not know to look underground for food sources, hence root vegetables entered our diet only relatively recently. Similarly grains are a fairly recent discovery.
Taking the above facts together, it is reasonable to conclude two things: for most of humanity’s history, a regular feeding schedule was very rare, and the proportion of energy we got from fats was historically much higher than it is now, and the proportion of carbohydrates was much lower. Our metabolism was never meant to be able to process the quantity of carbs that is recommended.
Eating carbohydrates causes the blood sugar level goes up. In response, our bodies produce insulin to get that level back down. Another function of insulin is to signal to our bodies to take all these extra carbs floating around and store them as fat for a rainy day. As with a lot of compounds, our bodies develop a resistance to insulin over time. It takes more and more insulin to decrease blood sugar levels by the same amount. And the signal to store energy as fat goes up over time. Some people are very lucky and seem to never develop insulin resistance, but these cases are few and far between.
The above reasons outline why the diets low in carbs (ketogenic, Atkins, low-carb-high-fat) and high in fat seem to be so efficient for so many people. Our bodies are designed to be able to burn fat for energy. A common misconception is that we need to eat carbs because the brain requires it. While it is true that the brain requires carbohydrates (some estimate that the brain needs around 25% of its energy demands in carbs), our bodies are able to produce all of these carbs on their own via a process called gluconeogenesis, where the liver generates glucose from non-carbohydrate carbon substrates such as lactate, glycerol, and glucogenic amino acids. This process can provide the brain with all the carbs it needs.
Another common belief is that you need carbs in order to be able to engage in aerobic activity. Our body can take fat cells from our adipose tissue, turn them into fatty acids, which in turn get converted into ketone bodies, acetoacetate and beta hydroxybutyrate. The main problem is that it takes the body a certain amount of time to get adapted to burn fat instead of glucose to produce energy. As a matter of fact, that adaptation period is commonly referred to as the keto flu, because most people feel terrible for a period of a few days to a few weeks. However, once you are adapted, burning fat is actually more efficient for aerobic exercise. Tests have shown that for a constant output of work, the body requires less oxygen to produce the same amount of ATP using ketones than using glucose. The trade-off is that maximum output of force is lower when fat-adapted versus glucose adapted. It should also be mentioned that for endurance activities, it will generally take several months for fat-adapted individuals to get back to peak performance.
Most of us heave about essential fatty acids, linoleic and alpha-linolenic. They are the building blocks for omega-3 and omega-6 fatty acids respectively (the proportion of which is severely disturbed due to our diets, specifically seed oils consumption, which will be discussed in another post). Our bodies can produce all other forms of fat we need in our biochemistry. The same goes for essential amino acids, whose individual names are not that well-known (phenylalanine, valine, threonine, tryptophan, methionine, leucine, isoleucine, lysine, and histidine). Other amino acids can be synthesized by our bodies. What few people realize is that there is no such thing as an essential carbohydrate. It is entirely possible to survive without ingesting any carbohydrates, as the Inuit people prove. They eat almost exclusively meat and fat, since fruit and vegetables are very difficult to come by in the far north.
One last thing we would like to mention is energy reserves. Glycogen is how carbs are stored in our bodies, mostly inside muscle tissue and in the liver. The average adult has between 400 and 500 grams of glycogen in their bodies. Carbs have about 4 calories worth of energy per gram. That means we store between 1,600 and 2,000 calories of energy in carbs. Contrast this with fat. Let’s consider an in-shape individual who weighs 180 lbs and has 10% body fat. That’s 18 lbs of fat, which at 454 grams per lb translates to 8,172 grams. Fat contains about 9 calories per gram, so the fat energy store for that individual is 73,548 calories. In truth, very few people have a body fat ratio as low as 10%, so most of us walk around carrying about 100,000 calories worth of fat (women tend to be smaller and have higher body fat than men, so likely the number is valid for them as well).
We hope that this overview has given you some food for thought (see what we did here?). Nutrition is probably the single most important factor to influence longevity, and has the most misconceptions, wishful thinking and outright lies associated with it.
Join us next time when we will discuss not what we eat, but when we eat.