Can you take food ie sweets crisps eg in main luggage when travelling to America?

As long as they fit in your luggage I don't see why not. When I traveled back from London to the states I took candy on board and was planning on packing a few small bags of hula hoops ( oh how I miss them!!) but I ended up eating them in the air port. I got them through security with no problems if that's your question. Oh and PS we call them chips :-) but you probably already knew that!