I was there two weeks ago.
They have the normal breakfast stuff (cereal, fruit, bagels, donuts, etc.)
Very light snacks in the afternoon (pretzels, goldfish, cookies, pb&j).
Evenings had cheese/crackers/dips, some fresh veggies, soups and one other hors d'oeuvres (changes daily).
Later at night, they had a nice sampling of desserts.
It probably hasn't changed since last summer, but it has changed significantly (for the worse) in the 10 years I have been going to YC.