Even more intense, there's this book of observational research performed by Jewish doctors in the Warsaw Ghetto as they and their communities slowly starved to death.
https://theconversation.com/warsaw-ghettos-defiant-jewish-doctors-secretly-documented-the-medical-effects-of-nazi-starvation-policies-in-a-book-rediscovered-on-a-library-shelf-182726
"With final deportations of the few surviving Jews underway and his own death imminent, Milejkowski wrote of the dark, yawning emptiness of the ghetto at that moment, and the horrifying conditions the doctors had labored under to conduct and record the research."
Block quote from the article of Milejkowski's words:
"What can I tell you, my beloved colleagues and companions in misery. You are a part of all of us. Slavery, hunger, deportation, those death figures in our ghetto were also your legacy. And you, by your work, could give the henchman the answer ‘Non omnis moriar,’ [I shall not wholly die]."