What exactly is the lowest number of calories you can eat and not go into starvation mode?

Hard to avoid. When you force the body to burn fat & not allowing your body to get that needed energy from the food u eat, u r n starv mode. As long as the intake is healthy and the body burns fat instead of muscle u are in good shape. The 2 words have a bad wrap because of the useless fad diets that end up burning muscle. The key is to use medicine to help in wt loss. In general 800 calories is lower limit.