Should I be upset with my parents for this?

I think that you should be very grateful to your parents for seeing that you were well fed, with healthy food in spite of their relatively low income. They did their best for you. And they did what they thought best in not telling you what you were eating. Would it have been better for them to be up front? Perhaps, but you shouldn't be upset with them about it. You should be grateful. And your Mom stayed home with you to give you a good upbringing, and a secure home. It would have been easier for them to both work, live more comfortably, not have to hunt, let you go to school with the house key hanging around your neck. But instead, they chose YOU.