According to them, some people have an affinity for spicy foods, while others prefer the blandness of plain food.
Literally "one man's food is another's poison and it's all thanks to genetics.
An early discovery of the relationship between DNA and taste happened in 1931 when a Chemist named Arthur Fox was working with powdered phenylthiocarbamide (PTC). Some of the powder puffed into the air and his colleague complained about the bitter taste. Fox had no idea what his colleague meant. To Fox, the PTC powder had no taste at all.
This led to an experiment among friends and family to see how the taste of PTC was perceived by others. The results varied between extremely bitter and completely tasteless. It was eventually discovered that the taste of PTC was related to TAS2R38, a gene that affects taste buds. The specific variation of TAS2R38 possessed by a person determines if PTC tastes bitter or like nothing at all.
The different gene variants are referred to as “tasting” or “non-tasting.”
A 2005 study discovered that TAS2R38 variations also affect how much a child loves candy. Children with two versions of the bitterness “tasting” gene were more likely to favour food and drinks with high sugar contents.
As for people who do not particularly enjoy sweets, another genetic influence may be at play. Some people are categorized as “supertasters". What this means is supertasters inherited more taste buds than the average person, which causes them to become overwhelmed by certain flavours. They avoid foods with strong flavours, including very sweet desserts, so it is not surprising they shy away from too spicy meals.
Though our food preferences have a lot to do with genetics, we build many complex associations with flavours and scents that can override our DNA.