Book Identification: Humans, stuck on alien planet, cannot eat food, have to teach aliens technology to survive

Question

Another one of those nagging memories from high school... I read it as a paperback in the 1990s or so. It's part of a larger cycle or series of book, which I remember only because one of the three humans protagonists (2 men, 1 woman) is an overweight merchant prince of some sort that had appeared in another story I half-remember. The three are on a trade mission to a planet who's pre-industrial aliens look like winged bears when their shuttle gets destroyed, and their means of communications confiscated. For some reason they can't eat any of the food on the planet since it's toxic to them, so they have to ally with a faction of the aliens that friendly to them to try and overthrow the flying bear government before they starve - and they do so by teaching the aliens and giving them rudimentary tech, like machine guns that shoot darts.

This whole thing probably sounds like a rambling dream, but I know for sure this book exists, even though google seems to have no idea what I'm on about. Anyone here has any clue?

Answer 1

I think this may be it.

War of the Wing Men, by Poul Anderson

From this summary:

their shuttle gets destroyed

Only three humans survived the wreck of that space-ship on the little known planet of Diomedes.

one of the three humans protagonists (2 men, 1 woman) is an overweight merchant prince

One was the beautiful ruler of a distant colonial world; another was the fat, slovenly owner of a great Solar trading company; the third was a handsome, blue-eyed engineer.

had appeared in another story

This is the first in a series of novels.

they can't eat any of the food on the planet since it's toxic to them

The survivors had food for only six weeks, for the native food was one hundred percent poisonous to people.

they have to ally with a faction of the aliens that friendly to them

So in that limited amount of time they had to gain the trust of the winged barbarians who held them prisoners, end the terrible war that these Diomedians were engaged in, and persuade the wing-men to carry the three across the thousands of miles of unmapped territory to the single Earth spaceport.

There isn't an overthrowing of the government, but there is a war.