Ice cream, doughnuts, pizza. This summer’s giveaways have been taxing on our bodies, but today’s heart-clogging bargain may really take the cake. The Cheesecake Factory is celebrating its 30th anniversary, conveniently scheduled on National Cheesecake Day, by offering slices of any of its 30+ cheesecake variations for $1.50 all day long (limit 1 per guest). Since the offer is for dine-in guests only, don’t expect to waltz out of the Factory gorging on cake without…