I feel like in general people tend to have the opposite effect from adding more exercise, even walking – like it causes stalls- BUT this doesn’t mean that the regular fat loss on the diet isn’t happening- I actually think for something low impact like walking, it’s probably just causing a little water retention. It’s one of those things I think you won’t know how your own body responds till you try it.
For myself when I was on the hCG Diet, if I took an evening neighborhood walk with my husband like we liked to do, I could be almost sure that I’d have a zero loss on the scale the next day. But again, I don’t think a leisurely walk like this – seriously just strolling – was preventing weight loss – I think it was just water retention – but it’s something you have to decide if you’re mentally/emotionally okay with. Some days I didn’t want to deal with it so I’d purposefully stay in.
Will the walking increase your weight loss? Overall, in the grand scheme of your whole round, it’s certainly possible. I never did it enough to know if it would have or not. What I like about walking is it gets your blood flowing and seems like it would be good for helping your body clear the toxins it’s releasing from your fat as well.
As far as more intense exercise goes, that does seem to backfire in a bigger way that work against your goals, I have an article on exercise during P2 hCG here that discusses this further if you’d like to see that.