Long long time ago, the human race was just evolving, and was learning how to cope up with health, hygiene and disease. I don’t know what ‘era’ or ‘age’ it was. Monolithic, bronze, stone or some yuga like dwaparyuga, tretayuga…etc. But it was an era when diseases spread fast, even simple ones like lose motion ! And people died of these little diseases. This was way before humans knew the benefits of personal hygiene or fresh cooking. I am talking about like really old times.
But we were evolving. There was this one guy who took bath everyday (probably because he liked it). Lets call him the ‘clean guy’. He even had bath multiple times a day. He had learnt the art of cooking over fire. He knew how to make fire, and how to use it to roast or cook. So he cooked everyday in his cave. And he had bath before cooking, after cooking, before going out, after coming back to his cave…all the time! Now, other people who did not know how to cook, would hunt animals or get fruits and vegetables to this guy and he would cook and serve them fresh cooked stuff. Also since bathing and cooking is all he did, he had lot of spare time on his hands for art. He made sculptures and decorated them. Other people who visited the ‘clean guy’ loved his sculptures too.
And then one day, there was an epidemic. Humans caught a strange infection through air, food and touch. Since they never had bath or cooked food daily, the disease spread very fast. Only one person was not affected. The 'clean guy'. Everyone looked at him with admiration. He looked like the wise one now. They went to him for help. He kept serving them cooked food. Since the food he served was hygienic, it slowly cured rest of the people.
So, thus was born prasad - that cures all illnesses, the pujari - the wise one and God - his sculpture and creation in spare time.