I average $325 a month for our family of five, just food, no home, personal or pet supplies in that number. We eat Flexitarian. My kids eat as much as I do. Only one child eats as much F&V as I do, the rest of the family lean more heavily on carbs and proteins.
My biggest tips:
-Shop the loss-leaders and have a food storage system for bulk buying(freezing, canning, dehydrating)
-Make a menu for a few weeks at a time, from what's already stocked in your pantry and freezer(I limit meat centric meals to Wednesdays and Sundays)
-Use recipes with less ingredients/ make cheaper in-season substitutions/ embrace simplicity(pbj and an apple every day has literally raised millions of children into healthy adults-kids do fine with a different balance of nutrients than adults...carbs and fats are good for them)
-limit shopping(I shop every three weeks and have hubby pick up perishables after work as needed)and don't waste food(I even save the outer peels of onions and carrots to make veggie broth)
-Stop being so darn picky. Don't feel like eating spinach pasta bake and wheat bread tonight? Want a roast with all the trimmings instead? Tough. Remember when you were a kid and you had no choice about what mom made? Might not be something you loved but you could usually eat a side or two and some bread. Or you ate some of what you didn't like very much because you were hungry and it was there. A lot of people go crazy when they get out of mom's house and can now choose eat whatever they want. It then becomes all about that, their favorites all the time, to the detriment of their wallet and waistline. Start cooking like a mom. Don't make what you hate, but make the frugal, "It's Ok" stuff too.
-Soup and bread. Make your own broth from veggies scraps and carcasses. Make your own dumplings and noodles. Throw in lots of those loss-leader veggies you bought cheap and threw in the freezer. Make a loaf of homemade bread with bulk-purchased flour and yeast.
-Learn to cook. A lot of people think they know how to cook because they learned 30 recipes and make them well. That's a good start but won't generally help to save any money on food. A good cook can look at a bag of 10 ingredients and think of at least 10 different meals to make out of them. My mother and both my grandmothers cooked like this and I learned from them. I'll gave you an example why limited cooking skills can cost you money. My MIL didn't like to cook and she had super picky kids. She would make a rotation of about 20 meals, exactly the same way every time. They were good and nutritious meals. But here's the problem, she had the same shopping list at all times and paid full price for her ingredient list every time. Once when I came over for a visit, she was out of pineapple juice for her sweet and sour sauce. When I suggested she use the orange juice in her fridge as a substitution, she looked at me like I'd asked her to swap in pickle juice. She decided to drive 25 minutes to town and back for a can of pineapple juice. Yes, their food spending was astronomical. Learning to really cook will give you plenty of ideas what do do with that half eggplant, chicken scraps, rice flour and slice of American cheese that are leftover from other recipes.
-Be willing to spend the time. I cook like a 1950's housewife. I'm in the kitchen a good 10 hours a week. I enjoy cooking and baking so it's no hardship to me. Glad I don't have to do it in high heels and a frilly apron though. ;)