On the contrary, the game won't ensure more food than one banana -- so long as there is any other 2F resource tile of any kind, and we know there is. The game will also add food if there were not initially 4 resources, but we don't know anything about that. 4 resources together is rare, but hardly unknown.
1N gives up one of the three unknown resources, while gaining the gems -- a known, very valuable resource. There is no source of early commerce other than gems/gold/silver. This does increase the risk somewhat of getting a low-food capital. But it does not increase this chance a lot, and in any case I don't think a capital with only a 2F surplus is such a problem, given its siting in the middle of all grasslands.
Here's a question to help think about this. Say that you knew for certain that there was a pigs, a corn, a banana, or a rice, on the tile 2S1E. Would you SIP? If it were a banana or a rice I would move north.
Kossin will decide and he is better than I am. Maybe trading food for commerce is a worse idea than I think.