We've been in your shoes with the Whole Foods thing. I won't lie; it was a hard adjustment to make. We gradually stepped our grocery bill down from $2500/month to $1200/month (includes household products and paper goods, and occasional meals out). As kids grow they start to eat more, my 9 year old eats as much or more than us, so we're actually feeding more people on $1200/month now than we did on $2500/month five years ago.
The first cut was no more wine, fancy cheese, and the salami my husband liked to buy a lot of in tiny packages. And fewer nice cuts of meat, no more baby back ribs, cut down a lot on breakfast sausages and fancy packaged fish sticks the kids liked. That got us down to $400/week.
We stayed there a while, then decided to cut another 25% to $1200/month. To do this we had to change where we shopped. I now buy all our fruit, cheese, coffee and cereal at Costco. And some other things, like spaghetti sauce and the kids snacks for school. We also cut our meat consumption and are eating more affordable cuts. We still buy most of our meat and a bunch of other staples from WF but stick to their store brand, and only go there once a month instead of several times a week.
Two other things that helped were to make a shopping list and not buy things that are not on the list, and we opened a second bank account with just the grocery money in it -- when it's gone we have to stop buying until we fund the account again.
Edited to add: we are a family of 5 with older kids -- the kids eat as much as we do, sometimes more. I'm glad we worked on our food budget when we did because otherwise we'd have a much bigger problem on our hands now.