Does the radius of earth effect weight?

Yes, in a way.

If the radius of the Earth decreased but it's mass stayed the same, then the forces "pulling" on you (weight) would increase and you would be heavier.

If the radius of the Earth increased and the mass stayed the same, then you would be lighter.

You would actually weigh less on the top of Mount Everest than on the beach of Honolulu.

BTW: This is not a good idea for a weight loss program.