This is a perennial question, first asked by (I believe) Lucy in the Enid Blyton's XXX of Adventure series (Castle of Adventure, Island of Adventure, and so on), and more lately, by kitchenhand on his excellent blog, What I cooked last night. My answer is I don't know, but also, who cares, because it does, and we should just accept this and then go forth and eat as many meals out of doors as the weather will permit.
On my writing weekend, I ate most breakfasts and some lunches on the deck, and all snacks on the beach. Dinners were formally served in the dining room, but the appetizer course was eaten on the deck, with various forms of alcohol. As Virginia Woolf is my witness, it did taste better. See above, a 7-layer dip that was devoured not long after this picture was taken.
I took brownies (see here), and made a curried vegetable dish, for which there is neither picture nor recipe. It was the kind of dish which arises out of what vegetables are available and look good (onions, green and hot peppers, potatoes, corn, cherry tomatoes) and comes together with a pinch of this and a grating of that.
We were also well-supplied with chocolate, which as everyone knows is crucial to the writing process.