Just a heads up that this achievement is glitched. I completed the game on Hard difficulty without losing a battle (I did reload when I was about to lose though I imagine that must be legal). I didn't even unlock the regular "Hard" achievement, just the one for normal difficulty.
Didn't have anyone die of hunger nor get low morale and didn't get any of those achievements either.
Tip from
Sir Lagselot :
"I've spoken with Stoic and their suggestion is to change the difficulty to hard BEFORE importing a TBS1 save, then continue to play through the game (w/Hard difficulty), and it should pop after the varl defeats the final foe."Myself, I didn't even import a game though, it still didn't count.