Playing devil's advocate here a bit...Sometimes it is actually cheaper to eat a lot of processed foods/carby foods as they're commonly promoted through in-store sales and manufacturers' coupons. This holds true with many diet foods such as Smart Balance, Smart Choices, Healthy Choice, Weight Watchers, Slim Fast, Atkins products, etc... With coupons, sugary yogurts can be as low as $0.10/container. Compare that to Fage or any other full-fat "choice" yogurt and there's a drastic price difference, even when using the occasional coupon on said choice yogurt.
Before being quick to judge, watch if the people hand over a stack of coupons and then watch the final price they pay. I think it might surprise you... (NOTE: this is usually not the case at Whole Paycheck.)
Most "frugal" guides advocate cutting ground meat with oats and other grains. Yeah, blasphemy for all of us here, but it is essentially reducing the cost per serving.