Started recently, paleo diet (caveman diet, stone age diet) claims that the only way to stay healthy is to follow the diet which your body has evolved to. According to some opinions, the first humans were carnivores and got majority of their calories from meat. Followers of this diet think that our organisms just didn’t have much time to adapt and evolve to our rapidly changing lifestyle and that heart diseases, high cholesterol levels and diabetes are the consequences of consuming foods unfamiliar to our ancestors.
Starting with hunter-gatherers, we imagine our ancestors as meat eaters which were eating berries and roots accidentally. But watching small groups of hunter-gatherers that remained until now shows that hunts actually finish successfully quite rare (even now, with more advanced weapons) and that the diet of caveman, more likely, mainly consisted of fruits, nuts and plants with a small amount of meat. Same conclusions were made by scientists, who discovered that our guts are longer than the ones of carnivores and pretty similar (with some differences) to those of herbivores. Judging on the structure of our jaws, our ancestors were omnivores, but probably during the Ice Age, where there was less plant food, they turned to eating more meat. Later on, with the invention of agriculture and cooking, people had to adjust (once again) to digest processed food. At this period people went back to mainly plant diet, experts say that the ratio of plant to meat consuming increased to 90%/10%.
The ability to digest certain food is determined by bacterias in our guts and really depends on who your ancestors were. If you were born in the Arctic, where Inuit and other groups traditionally got as much as 99 percent of their calories from seals, narwhals and fish, you can easily survive with meat only. But if you were born in Europe, active meat eating is a short way to heart diseases. Interesting part is that different ethnic groups have different bacterias. Well known facts: only small amount of Asians can digest milk, but instead of it, Japanese, for example, developed the ability to digest seaweed. These facts apparently mean that there is no food to which our body evolved to. Yes, meat and simple sugars are easier to digest: the first – because of it’s identity to our organisms, the second because the procedure of digesting is quite fast: the absorption stops at the small intestine. Cellulose – a base of all plants, is almost indigestible by humans and is a part of fiber that is useful in moving food through the digestive tract quickly and efficiently. Diets high in fiber are thought to lower the risk of colon cancer because fiber reduces the time that waste products stay in contact with the walls of the colon. And let’s look at it from the other side: digestion is an energy consuming process. The harder to digest – the more energy is needed. Do you remember about negative calories (like celery, for example)? It just takes more energy to break down and absorb the celery than the celery contains. Good example for those who track their weight. More than that, vegetables and fruits also are great (and sometimes the only) sources of vitamins, folate and fiber which are essential for our bodies.
As it was said above, people are omnivores with the ability to adjust to different food conditions. But considering the feeding habits of our ancestors and therefore the structure of guts, we are meant to eat more fruits, vegetables and nuts. Sometimes people think that everything was better in the good old times and regarding the diet it is probably true.