A healthier you is a more happy you
If you are serious about being an actor then you need to understand that you are your product, you are what you are selling out at the market.
A car salesman will make sure the cars are nice and shiny and well oiled before showing them to a customer, when you are selling your house you give it a lick of paint and fix all those niggling little jobs you have been meaning to fix for ages.
As an actor you need to make sure you are in tip top condition, make sure you are nice and shiny and well oiled too!
Being healthy and happy is a gift you can give yourself.