depends on the type of pack and where your going for this whole question.
if your in a cool area where you will have a stream nearby, you can use that stream as a form a refrigeration, keeping perishables cool and good, also you may need a tougher, bulkier tent if your in a cooler area since you don't want to freeze.
but if your in a warmer area without many moving water sources, you may need to take freeze dried and non perishable foods instead,
also you will have more room in your pack because you may only need a tarp or a light tent for warmer weather.
you need to factor everything in before deciding to go backpacking, because you want to have as much as possible without having too much weight.