The immune system is like a guard at the gate, ensuring that foreign and abnormal cells do not pass. This system needs fuel to take on invading infections, and unless an underweight person is eating very carefully, he or she could easily starve this disease defense guard. That means that very thin people are at extra risk for getting sick during cold and flu season, and they could be at risk for more serious conditions such as cancer, which begins with abnormal cell activity. If you're very thin, check with a doctor or a nutritionist about dietary supplements that might be necessary to keep you well year-round.
Nutritional deficiencies can also lead to the next problem on our list. What is it?