Here's why I think eating out is more economical and more environmentally friendly than eating in: packaging.
When you buy food from a grocery store, you are paying for a lot of packaging that you also have to pay to have taken to a dump. Restaurants buy their food in bulk, so there is less packaging. That means your money is going toward your meal and toward the chef, the restaurateur, the waiter, the dishwasher, etc. They are all a part of your local economy.
When you buy food from the grocery store, you're usually supporting a chain that is headquartered somewhere else, [and paying] for a lot of packaging that just gets thrown away and for the trucking industry to deliver all of that food that sits on shelves in boxes.
Restaurants can afford to support local growers more easily, as well, because they don't have to let food sit on the shelf and rot while it waits for someone to buy it. The restaurant can go through all of its tomatoes, etc., in a night.
Grocery stores prefer to buy from large agro-industry farms, which, as we all know, have a serious environmental impact and are detrimental to local economies other than those in which the farms reside.
Restaurants have better refrigeration, so produce lasts longer there than at your home. How many boxes of lettuce have you bought only to have half of it go bad before you eat it? So then you're throwing away your money in the form of rotten food you didn't eat along with the box or bag or whatever it came in.
For grocery stores to actually make more environmental and economical sense than restaurants, they'd have to sell their food without packaging. Imagine going to your local grocery store with your own boxes and jugs and filling all of them up with food that comes out of dispensers, rather than coming in a box. That would be sensible.
Also, remember that grocery stores use enormous amounts of power illuminating their space. Restaurants use significantly less electricity, which lowers carbon emissions. And if you live in a well-designed city, you can walk to a restaurant even if it's like a mile away. This would also help solve the obesity problem in this country. You can't really walk to and from a grocery store, even if it's close to a mile away, due to all of the crap you'd have to carry back. Plus, on the walk back, your milk and eggs and many other items would go bad. Grocery stores, as they are now, are a waste.
— Christopher Blake Burgher