When we eat a good meal that does not have a lot of sugar in it, our body produces dopamine, which makes us want to eat the same meal again at some point. But let’s say you decide to eat the same meal, that does not have a lot of sugar, for every meal over the next few days. Every time you eat the same meal, the dopamine response in your body will continue to decline gradually after eating the meal, until you will have almost not dopaminergic response at all. When we eat sugar rich foods, this decrease in dopamine response does not occur.
Why has the brain evolved to pay special attention to new or different tastes?
The two reasons why it has evolved to do this are:
To detect food that has gone bad
To make us eat a variety of foods that have a wide range of micro and macro nutrients (The more variety we have in our diet the more likely we are to eat all of the nutrients that our body needs.)