Advantages of having been ill

I don't tend to talk much on here about having been ill, just the main problem of not sleeping that I have now. But I've been thinking about the positives to have come out of it. When I was really ill back in November I lost all my fittness but I also lost half a stone of weight in a week. At the time I was really worried, I know losing weight that fast is a bad thing! But as I clawed my way back towards fitness I never put the weight back on, the way I eat I would have epected to. Instead it's stayed off but I have got healthier again, now I'm getting fit again but I weigh less. This means that my power to weight ratio has improved. The question is would I have lost the weight anyway now I'm doing more endurance riding or was losing it when I was really ill lucky as now I am lighter?