Avatar Nutrition has a "calorie floor" built into the system that prevents calories from dropping below the level that we deem safe. This number is different for each person and is based on body composition and weight.
We don’t recommend that you diet long enough or hard enough to hit this calorie floor, as it’s the absolute lowest number of calories a person can eat and is certainly not optimal!
Fortunately, most people will never reach the calorie floor because of compliance issues. As calories drop lower, ravenous hunger and plummeting energy levels make it increasingly difficult to stick to low macros. As soon as this happens, we recommend that you switch your goal from weight loss to reverse dieting rather than waiting until you hit the calorie floor.