In the time of David HaMelech / King David a plague was killing 100 people a day. He thus instituted that people say 100 Blessings a day. People stopped dying.
Various types of blessings exist –
Blessings of Praise – like blessings on lightning, blessing on the new moon.
Blessings of Thanks – like saying thanks that we lived till today – on new clothing, new fruits, on new holidays
Blessings on Mitzvot / Commandments – like before washing hands, before putting on tefillin / phylacteries, before shaking lulav and etrog
The Torah (5 Books of Moses) writes “What Does Hash-m Your G-d ask of you – only to fear him” The Word “What” in Hebrew is “Mah”. Rabbi Meir Baal HaNess says the Word Mah similar to the Hebrew word – can be read as – “Me-ah” – meaning One-Hundred.
Meaning to fear G-d, Hash-m wants us to recite 100 blessings a day.
Why 100 Blessings A day?
He says that when Adam HaRishon / the first man – was created by Hash-m he was tall to the sky. When he sinned he was reduced to 100 amot. (1 Amah is 1.5 – 2 feet). Adam before the sin was a highly spiritual being. When he sinned – he changed to more of a physical being. (He used to have clothing of light (Ohr – with an Alef) – that were changes to clothing of animal skin / hide (O’hr – with an Ayin).
100 amot is the point – between heaven and earth. Adam’s new goal was to uplift the physicality into spirituality. Thus we recite 100 blessings a day – to change the physical – as food – to spiritual – by reciting blessings.
Are You Eating Soul Food
At times a soul is reincarnated to animate or inanimate object. When one recites the blessing on the food – if a soul was in that object – it is uplifted allowing it to go to a higher plane of existence. We are fortunate to be humans. Our soul was reincarnated to being a human – thus we have freedom of choice to elevate ourselves through spirituality or the opposite by pursuing pleasure without a higher purpose.