Some people are great at dieting and train somewhat inconsistently - for those people, getting on a great training program and following it will be the best thing for you.
If getting a great body was easy, every woman would look Jessica Biel, and every guy would have a body like Kellan Lutz.
Full-body workouts are great for someone who can only train a few times per week, as missing one day will be less detrimental.