I want to burn say 500 calories in 30 minutes. But I do not want to build any muscles in the process, I want to have a thin type of body, not one build with thick muscles.
A little bit of research said that kettlebells burn 400 calories in 20 minutes. However, it involves weights. I do not want to have thick arms or legs saturated in muscle.
I thought about running up and down the stairs for 30 minutes. Or possibly walking up stairs carrying a heavy weight. I am worried however that this will add thick muscle to my legs.
What do you suggest as a good method for burning calories and still preserving a thin body?