text: It depends on what you mean by nice upper body. Strength or appearance? You will not be able to see the results unless you tone down (or up I guess) overall. You can target muscles but you can't spot reduce. Example: You could have awesome abs but never see them because all you've done is crunches and haven't toned the rest of your body. Cardio and weight lifting are great ways to reduce excess fat. If your body is already trim, then you will see your results. There are many areas of the upper body to work: triceps, biceps, deltoids, lats, traps,... Push ups and sit ups will not engage all of these muscles.