Why would someone need to eat chametz on Pesach?
Answer: We would be happy to explain the general concept. We are choosing not to name specific conditions however, because there are many circumstances in which someone would be required to eat chametz. We can't list them all, and we don't want to imply that only the ones listed are valid.
It's important to know that many (but not all) people have enough flexibility and choices around eating that they can eliminate chametz for Pesach, and still get enough nourishment. Many Ashkenazi Jews are able to get enough nourishment when eliminating both chametz and kitniyot, while others may either choose to, or be required to, eat kitniyot in order to be fully nourished.
Other people may have chronic conditions or disabilities where they have very little or no flexibility around food. In fact, they may require very specific foods or meal replacements year round. If these foods contain chametz and they are required in order to survive, they are not only allowed to be eaten, but there is actually a mitzvah to eat them.
Others may have acutely dangerous conditions but more flexibility with foods, however, if there is even the possibility that changing their foods for Pesach would be detrimental, we do not risk endangering them.
We would like to close by thanking the people who asked us this question. We are committed to raising awareness and providing education around issues of health and mitzvot centered on food and eating. Your questions help guide us in this process.