I have lived on that before in the US and it’s not that hard. You just need to buy macro-nutritionally dense food at super markets - rice, chicken, beans, cooking oil, butter, oatmeal, noodles, etc.

Of course the problem is that you don’t get a super varied diet which can be problematic both mentally and nutritionally. It can also become a bit harder to incorporate fruits and veggies into your diet when they’re not on sale. And you also need to cook a decent amount

When I was in Rome I found that I could eat on less than $20 a day extremely easily so unless you’re going to restaurants every day I’m not sure how you spent so much