I've been told I got an excellent body for Judo, but I practice karate. I'm 116kg at 178cm.

I always teach my students that a good style and karateka will mold their karate around them NOT mold them around the Karate.

What you find is that Karate is an Aerobic exercise whereas to build Muscle form etc requires Anerobic exercise. they go against each other. another Aerobic exercise is Running, I've never met a Bulky Long Distance Runner and Short Distance runners tend to be bulkier is statue.

Take Football (soccer for non-Europeans) comapred to Rugby/American Football. there are size differences there too.

Best thing is exercise your body to assit your Karate not hinder it. Cycling Shortens the Hamstrings whereas we need to lengthen our hamstrings etc. if weight-training high reps low weights etc

Good Luck
A man is but the product of his thoughts what he thinks, he becomes.