Fat contained in fat cells exists in the form of triglycerides, and muscle cells cannot directly use triglycerides for energy. The fat must be broken down in glycerol and free fatty acids first, then enter the bloodstream where they can be carried to the muscle cells for burning. So there really is no reason for the muscle to preferentially use fats from the fat cells adjacent to it—it is using up the fatty acids in the bloodstream and doesn’t care whether those fatty acids were released from the fatty area right next to it or from the other side of the body.
