It will definitely affect your weight loss if you do more than the recommended amount in your first few weeks. Basically what happens is that your body will go into starvation mode which means that it hangs on to every ounce of fat as reserves, and instead starts to use up muscle as fuel to keep going, which is obviously a bad thing, especially since your heart is one of those muscles. So the aim is to do gentle exercise which will tone you, but you dont want to be burning lots of calories which is what will send your body into shock and starvation mode.