I don't understand this. Rice, potatoes, vegetables are still cheap here. I guess if you're looking at restaurants, this is true. If you are with a group and have to go eat somewhere, they usually provide healthy options which are not too expensive compared to the unhealthy ones (though sometimes, that's just due to smaller portions).

Maybe you have a different experience, having just visited, instead of living here.

addendum: it also depends quite heavily on the area's cost of living, apparently. I just bought a sack of potatoes for $0.40/lb, whereas https://news.ycombinator.com/item?id=16448984 says potatoes in LA are $1.88/lb (nearly 5x as expensive).