
Originally Posted by
Xenoxorph
Cardio can deplete glycogen(source of energy) stores found in the muscles. Depletion of glycogen can cause loss of water inside the muscles. Making you look "flat". Somewhat an illusion that makes it look like you lost muscle mass. But in fact, it was just water/glycogen weight.
Cardio will help since it will make you burn more calories, but 2/3 of the equation will come from proper diet. Cardio combined with a calorie deficit will make you leaner. The leaner you get, the more visible your lower abs will be