As a human being you are a double-edged system.
About 20 million years ago, there was a gene mutation in an ape, which was the common ancestor of all modern apes and humans today. This mutation saved the species of the apes from extinction. It was a winning gene mutation, and today every ape and human still possess this mutation. The weather changed drastically 20 million years ago where then apes lived. Before the weather pattern change there were massive forests with plentiful food. But in a relatively short period of time the forests became scarcer, and seasonally there were long food-lacking periods. This was very difficult to survive for apes until this particular genetic mutation showed up. The mutation involved a gene which helps apes (and humans) turn fructose very easily into fat (aka stored energy) – and it also gave us the craving for fructose.
The mutated gene allowed our ape ancestors to ‘store’ fuel under their skin. This mutation saved the ape species from extinction (since no others stayed around without this gene). This is why you and I can gain fat. It is pretty ironic that what saved our ancestors and carried us here today, is basically slowly killing many people. The pandemic of obesity triggers type-2 diabetes, heart disease, and many gastrointestinal diseases including some cancers as well.
Combine this special fat growing capability with one of the ancient default settings of the human brain: conserve energy above all. Basically, simply speaking, don’t move if you don’t have to. This made sense right up until the industrial revolution because our lives in the wild (and even on farms) were active, so when you didn’t have to, it was wise not to waste your energy.
This default setting is deeply engraved in our brains and that is why people move so little nowadays, because we ‘know’ on a primordial level that ‘we don’t really have to move, so we shouldn’t’.
Just think of a group of lions in Africa as a similar example; they move when they have to, otherwise they sleep/rest to save their energy.
So, the combination of the massive ‘fat gaining capability’ and the default behavior to ‘only move when you have to’ is giving us ordinary people a hard time today, making all of us fatter and more out of shape than we ought to be; or we would like.
So, what should you do?
1. Eat seasonally by paying attention to vary your diet season by season. Only eat the ‘sweet’ stuff when it is in season!
2. Find good, meaningful reasons to move. I am not talking about exercising only. I am talking about walking to dinners daily, taking the stairs instead of elevators, do sports you enjoy for entertainment with friends and family, organize movement into your vacations so it becomes a journey instead of only sitting and sipping drinks by the pool.
We could call this one of the main challenges of a ‘Caveman’ in our ‘Modern’ World.