What is the minimum caloric intake for an adult? I'm not talking about a healthy diet. There's plenty of advice on that. I'm wondering what the absolute limits of H. sapiens are. When there's a multi-year famine, and the body is willing to shut down as much of its capacity as possible without actually failing to function for years at a time, how much energy is it consuming?
I know the Basal Metabolic Rate is a key factor to this, but the numbers I have seen for it are all "healthy" BMRs. I'm interested in the unhealthy numbers. For example, I'd consider maintenance of temperature optional for these circumstances (assume we have a temperate enough climate), and I presume heart rate and breathing will go down, decreasing those loads. Obviously there's limits as to how many environmental constraints can be addressed (if I knew what environments this was studied in, I'd likely know which studies to look for!). And obviously not everyone is the same, but that's an issue in every human study ever completed.