In an era without industrialized sugar production, sweetness was a very luxurious sensation. It brought high calories, but also made the brain secrete more hormones, which would soothe negative emotions such as sadness and pain. Hence, some people overeat and drink excessively when they experience heartbreak, primarily to intake sugar.
Without sugar, the primary sources of sweetness were honey and some high-sugar natural crops, such as sugar beet, a crop with a sugar content of up to forty percent and a very important sweet crop.
Regrettably, sugar beets were hard to grow in the underground city and even in this world. It was not just about food sufficiency, the light conditions needed for sugar beets could not be met in the underground city.
Sugar beets require a long period in high-light conditions for the starch in them to convert into sugar. This condition could not be met in the underground city or even in this world.
