Face overweight

About a year ago, the tree shrew had a funny tail from the rainforest in western Malaysia that appeared in newspapers around the world. The reason is that observations show that this species often drinks a large amount of alcohol. Their favorite drink is nectar from a palm tree species (this honey often contains alcohol due to the activity of some yeast in nature.)

Although drinking so much alcohol, the tree mouse didn't show any signs of getting drunk. They also do not suffer from diseases like an alcoholic often faces. In other words, they seem to have evolved to be immune from the effects of overdose.

This makes us think. Many people are now in a state of excess energy, with countless types of fat and sugar-rich foods around. Currently, excessive eating habits lead to many health problems such as obesity or diabetes.So, in principle, will there be a time when humans will evolve to the point that even if they eat a lot, they will not suffer the consequences?

It will be very difficult to conduct experiments on people to find the answer. In fact, such an experiment requires impacting both eating and reproductive problems in the participants;therefore, it takes at least 100 years to get the first results. Fortunately, some animals are very suitable to be the subject of this experiment.

Examples are diamondback moth, for example. Needless to say, caterpillars are a very good species. But less of a concern is that caterpillars can become very fat if they eat too much carbohydrate. For humans, excess fat is not beneficial to health. (Insects tend to choose food very carefully, and it is difficult to lure them into overeating: they are born that are not gluttony. However, they need a certain amount of protein, due to so if you give them a protein-rich but carbohydrate-rich diet, some of them will eat more carbohydrates than they need to compensate for the lack of protein.)

A caterpillar is eating.

Imagine two diets: a rich carbohydrate, poor protein; and a complete opposite. The caterpillars will enjoy one of these two regimes, they grow, mature, and are spawned with the same diet.Their children are then fed exactly like their parents. The process goes on.

After about 8 generations of worm generation, individuals in the high carbohydrate group tend to store less fat. In contrast, individuals in the low-carborhydrate diet group store this carbohydrate as fat.

Facing overweight (Photo: johnbledsoe.com)

Similar research results were seen in mice. In just a few generations, mice have evolved to be able to eat a lot of fat without being obese.

This result reminds us of another factor that may be involved in current obesity.

The reason we often hear is the tendency to increase fat intake stemming from past famine. Suppose 'saving genes' are interpreted as follows:

Reality: in agricultural society, hunger due to crop failure or war is a recurring problem.In fact, there have been 350 hunger due to crop failure in the last 2,000 years (in Britain alone this figure is 190).

Fact: hunger sometimes kills many people, especially children.

Hypothesis: people in normal conditions are still loaded with fat that is more resistant to hunger, and thus contributes this 'saving gene' to the next generation.

Conclusion: in modern society, when energy-rich foods are available, the ability to store the excess food of 'saving genes' turns out to be harmful to humans.

The theory of saving genes is still controversial, and there is no clear evidence to prove its content. For example, people do not know, whether fat people are better at fighting skinny people in hunger (although it seems that the answer is yes).However, in my personal opinion, the argument of the theory seems very reasonable.

But experiments on caterpillars show that the tendency of obesity may also occur even before there has been no starvation before. Worms that enjoy a high-calorie diet quickly evolve and become immune to excess energy; On the other hand, those with a tendency to store fat are the ones that have never had excess fat in family history.
This suggests that the obesity trend does not necessarily appear in people whose ancestors often suffered from hunger; it is simply that their ancestors were not allowed to eat a lot of donuts or cakes. Thus, the ancestors of the fattest of us may have never experienced hunger, but they are the least energetic.

Remarkably, redundancy is a characteristic of agricultural society. Yes, famine took place. But the period of time between famines often has a surplus period, and the richest members of society are often the most material members. For example, during the banquet of Pope Clement VI's inauguration in Avignon in 1342, the menu included 60 pigs, 1001 calves, 118 cows, 300 dog fish, 914 goats, 1023 sheep, 1,466. goose, 10,471 chickens, 46,856 cheeses and 50,000 scones. The whole number serves about 3,000 guests. Meanwhile, according to the record of Queen Elizabeth I reign, within a year, her entourage (about 600 people) at Hampton Palace ate 53 wild boars, 760 calves, and 1,240 heads. cows, 1,870 pigs, 2,330 deer, and 8,200 sheep. They also drank 2,280,000 liters of alcohol every year.

There are many factors - for example, what do you eat now, what did you eat when you were a child, how much exercise did you do, how much bacteria, bacteria in your gut, etc. - contributed to the formation and development of obesity. But we know that people live in different regions, from ancient times, have eaten different forms, and that ancestral tastes and customs leave certain imprints in our genome. People who have long been associated with cows, such as northern Europeans or East Africans, have evolved to digest milk better than other groups. The ancestors who ate a lot of rice, flour, and tubers now have better digestibility of starch.Therefore, it would not be surprising if different groups of people have different genes related to obesity, a result of past history of hunger and food abundance.