Evolved to eat meat: the logic of low-carb diets

If you're trying to search for information about weight loss and healthy eating it's nearly impossible to find good advice about what actually works and what doesn't. Contradictory information is everywhere; low-fat vs. high-fat, meat eating vs. vegetarianism, soy vs. dairy etc. On top of that, many diet and weight loss websites have their own agenda of selling information products or dietary supplements. Not to mention the huge number of fad diets which are supposed to make you look like a Calvin Klein model in four to eight weeks.

And here I am talking about low-carb diet, which was pretty much categorized as a fad some years ago, but now an ever-growing body of research is starting to prove otherwise. The principles behind low-carb way of eating are sound and result in better health. There is a lot of evidence that low-carb is not just another passing thing, but actually might prove to be the optimal diet plan that anyone can follow.

I have discussed the mechanics of low-carb diet in detail previously, so please refer to The how and why of weight loss article if you're interested in knowing more about what it actually is, and how and why it works. In this post I want to focus more on some of the logic and reasons of why low-carb simply makes sense.

Human species is approximately 2 million years old, and our prehuman hominid ancestors appeared on the face of Earth at least 4 million years ago. We have had all this time to evolve, to adjust to our environments, and essentially become as well-suited as possible for survival under the conditions that have existed for the past millennia - including obtaining our food by means of hunting and gathering. Agriculture, on the other hand, is only a 10,000 years old activity, yet it has drastically changed our dietary patterns.

Prior to agriculture the human diet consisted of seasonal fruits, vegetables, and meat. Dairy is also fairly new, as we developed lactose tolerance only about 7,500 years ago. In a hunter-gatherer society the amount of protein consumed was 2-5 times as much as it is today, and since plant-based foods that can be eaten raw do not contain large amounts of protein, it is safe to say that by far most of the protein came from animal sources.

The Expensive Tissue Hypothesis suggests, that it has originally been because of switching from largely plant-based diet to one that is mainly animal-based, that we have been able to develop as large brains as we have now. The brain consumes more energy than any other organ in human body, and meat has higher concentrations of energy than fruits and vegetables. Meat eating allowed our guts to reduce in size as less energy was needed for digestion. That available extra energy was then consequently put into the use of human brain which has grown to be three times the size compared to the brains of other primates.

Since the dawn of agriculture our glucid intake has increased 45-60% as we are eating grains and starch products instead of seasonal fruits and vegetables. Now pause for a moment and think: In evolutionary terms 10,000 years is a blink of an eye, yet we have brought upon us drastic nutritional changes. For 2 million years our bodies adapted to plant and meat based diet which was high in fat and protein. 10,000 years quite simply is not enough time for the necessary evolutionary changes to happen, so that we could actually operate on an optimal level while gaining most of our calories from carbohydrates. Not to mention all the highly processed foods rich in trans-fats, artificial sweeteners, and sugar that have emerged during the 20th century.

Archaeological evidence found on Egyptian mummies suggests that the switch from hunting and gathering to carbohydrate based diet has caused ailments such as tooth decay, cardiovascular disease, and obesity. Stunted bone growth caused by iron-deficiency anemia and infant mortality has also been far more common in agricultural societies compared to hunting and gathering ones.

Supporting evidence can also be found in more recent times: the Inuit peoples in Alaska have traditionally eaten a diet that consists 3-5% of carbohydrates, as their main food sources were fish, marine mammals, moose, and caribou. Despite high-fat diet obesity was almost non-existent among them, and type II diabetes was rare. In 1978, however, carbohydrates were already presenting 50% of the Inuit diet, and obesity and type II diabetes had become far more common. Similar pattern has been observed in all the other cultures that have switched from plant and meat based hunter gatherer diet to refined carbohydrates.

In light of this evidence and human evolution, we are built to work on meat and plant based diet. Yet paradoxically I'm sure everyone of us knows people who are eating fairly large amounts of carbohydrates and have no weight or health problems whatsoever. Similar to that, most of the world is still lactose intolerant. Not everyone has developed the gene that allows them to digest the complex milk sugar.

A recent LiveScience article suggested that the human evolution is actually accelerating, and the biggest recent changes are related to agriculture and its consequences. This could indicate, that some people have developed a better capability to digest and use grains and starches as an energy source. They may have also developed a better protection against associated illnesses such as type II diabetes. Similar to lactose tolerance, however, this does not apply to everyone.

And here is the catch why low-carbohydrate diets simply make sense. You probably won't know your own tolerance levels of carbohydrates, yet you have evolved on a meat and plant based diet. This means you can easily cut off carbs and sugars from your diet for at least two weeks and monitor what kind of changes that brings. The point is not to cut meals, count calories, or refrain from eating when hungry, but to simply avoid anything with sugar and carbs. Popular low-carb plans such as Protein Power and Atkins both start with a 2-week intervention period during which the carb consumption is reduced to about 20 grams a day. This period will also kickstart your metabolism to burn fat for energy instead of storing it.

And no, you can't die from lack of carbohydrates in your diet. Even though we have certain tissues that use glucose for energy, such as those in our eyes, the liver is perfectly capable of synthesizing all the glucose required.

After the first two weeks you can try gradually increasing your carbohydrate consumption while monitoring how your body feels. Each of us has different tolerances. I've found that mine is quite low, so I avoid all carbs except what I get from vegetables, youghurt, and milk curd for most of the time. Professional athletes or those doing high amounts of exercise will also have different nutritional requirements. If you're severely overweight, obese, or suffer from type II diabetes I recommend getting more information from books like Protein Power on how to gain optimal health and weight.