This advice is horrible and is one of the biggest myths in weightlifting. One of my friends is a painter and he's pretty jacked from doing it. There isn't any heavy weight involved, but all the ladder moving and brush strokes made his arms bigger just like the guy who does 5 sets of 5-8 reps in the weight room. I didn't think anyone but old laddies believed that myth.Sure it makes sense, but lose the the heavy weights. More reps is what you need. And of course, Cardio and what you eat is the key for what you want
Like most everyone has stated, muscle is the key element to increasing metabolism. Cardio is less important at this point.
Try alternating between heavy weights one day and moderate weights the next time.
And make sure you have some sort of protein food in the morning to get the metabolism up and running.