Oops, it doesn't look like 'Diet Rite day' is a national day..

Other days

coffee

Coffee Day
eat what you want

Eat What You Want Day
buddy

Buddy Day
slime

Slime Day
offer

Offer Day
pumpkin

Pumpkin Day
gum

Gum Day
bonang

Bonang Day
pick me

Pick Me Day
azonto is acceptable

Azonto Is Acceptable Day