Like others say, skeletal structure no. The rest will depend on how bulky you were up top and why, if it's musculature from sporting activity it will eventually diminish but it may take some time. If it's fat it might redistribute a bit. I was pretty scrawny to start with but even so the upper body area has still slimmed around my shoulders and back. I find that pulling the shoulders down and back as a natural part of posture helps to visually slim them.