I went through the same thing (I had over 3000 in food and they went through it very very fast). Thereafter had like three years of famine where they ran out of food constantly. They had to be monitored closely to keep them working on productive stuff and during crop season everyone harvest as fast as possible (if you drag them instead of letting them walk, they harvest more) PLUS forage until the berries ran out. I had to change their skills back and forth to the needed focus (food sometimes, research sometimes). They still ran out of food each year: several got very weakened plus two of my oldsters died, but they managed to get enough tech points to finally buy level 3. Thereafter all the weakened people got healthy again, except the oldsters who still hung in about 4 more years but then died. The game just seems to build this crisis in unless you save up and spend all your points on harvesting research. As others have noted, the safest way to play the game is to do that first. I noticed that putting the game on SLOW and going to sleep will generally give you enough points in the AM to buy the level you need, with SOME villagers still alive. The weakened ones can hang on quite a long time, and even when they go RED they can still reproduce! I had one elderly red give birth to two children in her 60's. In fact, they seem healthier when pregnant. After you get food back, keep the weakened ones eating. Health improves if they switch jobs occasionally, and farming seems very good for their health.