Should you have someone else do your grocery shopping?

In a comment made in response to my post lamenting New York City's insane grocery prices, one WalletPop reader explained how he cuts down on his grocery bills (edited for clarity):

I get my son to shop for me... It helps me avoid me from impulse buying. Thefirst thing I do is visit online grocery stores, prepare a grocery list & if I think the delivery fee doesn't make sense then I get Neil to pick up the stuff for me. I really think getting a person who doesn't like to grocery shop works because it doesn't put a hole in your pocket.

It makes perfect sense to me -- if you have a son who's willing to do your shopping for you at no charge. Most people know that making a grocery list and sticking to it is a good way to avoid overspending on impulse items. But I also wonder whether having someone else to your shopping is a good personal finance strategy: maybe if you and a friend swap lists and do each other's shopping, you'll both spend less? It seems a little complicated and most orders would probably get messed up in some way: "I wanted the light blue cheese dressing!" But if are looking to lose weight -- and can't help stocking up on unhealthy foods -- sending someone else to do your food shopping might be just the trick. It's sort of the idea behind programs like Nutrisystem.

I'm curious if anyone reading this has experimented with having someone else do their shopping, and what the results have been. Please leave a comment and I'll do a follow-up!