Here at the monastery we never just bake potatoes. We add winter squash and a pan of onions. Another reminder is that someone who lives alone needs to search for a fair amount of variety in his or her eating. This variety will motivate effort. Otherwise, there is a danger of getting into a rut and eating the same thing nearly everyday.
Variety is an important part of nutrition.
Perhaps the main thing a person who lives alone needs to do is sit down and think, give some time to questioning whether he or she is getting proper nutrition. It would also help to talk with a doctor or nutritionist and perhaps to read up on nutrition.