RE: Please help with definition
Best thing with cardio is to minimise muscle loss you need to keep the intensity VERY low (easy powerwalking level of intensity as a guideline). This will keep your fat burning efficiency high and avoid tapping into muscle glycogen and then muscle protein for energy. I'm doing just that at the moment (read my journal if you like for more detail). Keep protein high and take protein before and after cardio and you will minimise any muscle loss. The secret to reducing bodyfat and keeping muscle diet wise is to gradually lower your body's calorie intake so that it doesn't go into starvation mode and to increase your low intensity cardio work IMO. If you reduce calories gradually to drop by 500 a day total (i.e from 3000 to 2500 per day) and increase your low intensity cardio to an extra 500 calories a day then you can comfortably lose easily 2-3 Ibs per week but without Muscle loss.