Yes! You are absolutely right!
It's perilous to start the game at 2X speed because they eat very much, more than in normal or 1/2 speed. At the beginning, the food resources are very important.
But, when you have enough time to stay nursing your villagers, you may play in 2X for getting tech points faster (or another task) You just have, you and the kids of the village, to be on the look-out for mushrooms!!