It is often just misinterpreted and men end up totally messing up their style over this misconception that a round face is same as a chubby face. Round face is characterized by its round jawline and also a face structure wherein the distance between two cheekbones is almost the same as the distance from the forehead to the chin. Sure the cheeks can add good volume and accentuate the face structure but a thin guy can very well have a round face structure and a healthy guy can very well have a heart or diamond face structure but is also chubby.
Despite your weight, you must identify your face structure and only then can you find the style that will suit you best. This is very important as misconceptions regarding face shapes can completely alter the final look and can be an absolute disaster!