Yes I believe it is their hours, less to do with biscuits. Cats are usually more active at night. Oliver has decidedly taken after us (or WE have taken after cats should I say...) and a very much nocturnal, we have several play sessions a day but without a doubt he goes way nuttier after midnight than other hours. During the day his reaction is often almost lazy on the other hand. Yes we have to be careful to keep it down as much as possible as when Oliver runs around it sounds like a stampeding bull on the loose!!
He, at 7 months eats 2 main meals when we get up and then a supper around 21, nibbles (dry food) during the day (afternoon) and before we retire. We may have to consider cutting down a little of his food as he is getting quite hefty and he is getting neutered in 3 days. We don't think it is because of fat, he seems quite solid but his built is not the cobby type, or big boned, I am not sure if we should let him get any heavier. I guess we need to check with the vet about that when we have to bring him in come Saturday...