It is a fact that too much aerobics destroys a lot of muscle even if a lot of protein is eaten. It is preferable to just do enough exercise to help deplete your glycogen store (will not be the max of 2000 kcal if you have been in diet for some days) and then lose adipose fat (instead of a little adipose and significant muscle fat and tissue) when you are simply slowly metabolizing for sustainance (rest, sleep, office work) instead of doing aerobic/cv workout that requires energy too quick for it to be providable solely by adipose fat.

If this style of nutrition (i.e. a lot of protein, with low carbs, e.g. 2xprot and 1xcarbs) is followed with this kind of exercise (e.g. 2xweek 30mins cardio, plus 2xweek half-body free-weight sessions), then muscle mass will at least be maintained while fat will be getting lost. How much this will be the case depends on the particulars (with genetics a major factor) but it will always be the case. If you do the calc, you will see that low-fat 2xprot, 1xcarb diets will always gives you less calories than your sedentary BMR.

It would be good if right in the middle of your ripping period you took, for 3 or 4 consecutive days, instead of 2x protein 1.2x protein. Some researchers say that this boosts your metabolism, fat burning and muscle building.

One of the more serious problems associated with abnormal gain of muscle mass is heart failure. While for most people gaining muscle and losing fat is desirable, a body builder is at risk of producing more muscle mass than the heart can handle. One pound of fat contains about 3.5 miles of blood vessels, but one pound of muscle has about 6.5 miles. Hence, additional muscle causes the heart to pump more blood. Some people that have too much muscle will be very strong but will not have a healthy aerobic endurance, in part because of the difficulty of providing oxygenated blood to so much tissue.