Why can't people use food stamps to buy hot/cook foods?

[Puzzledtraveller]

9. From the USDA

http://www.fns.usda.gov/SNAP/rules/Legislation/about.htm

The First Food Stamp Program (FSP) - May 16, 1939-Spring 1943

The idea for the first FSP is credited to various people, most notably Secretary of Agriculture Henry Wallace and the program's first Administrator Milo Perkins. The program operated by permitting people on relief to buy orange stamps equal to their normal food expenditures; for every $1 worth of orange stamps purchased, 50 cents worth of blue stamps were received. Orange stamps could be used to buy any food; blue stamps could only be used to buy food determined by the Department to be surplus.

Over the course of nearly 4 years, the first FSP reached approximately 20 million people at one time or another in nearly half of the counties in the U.S.--peak participation was 4 million--at a total cost of $262 million. The first recipient was Mabel McFiggin of Rochester, New York; the first retailer to redeem the stamps was Joseph Mutolo; and the first retailer caught violating the program was Nick Salzano in October 1939. The program ended "since the conditions that brought the program into being--unmarketable food surpluses and widespread unemployment--no longer

I have been a SNAP worker for about 4 years. The reason I hear most often for the restriction is nutrition. I also have heard that the original intent was to assist farmers who had a surplus during the period of recovery after the Dustbowl. It seems this would have extended to Grocers as part of that program via the Orange stamps.