As a sedentary male over 50, I average close to 3000 calories a day. On MY diet I have gone as high as 4400 calories and as low as 800 (I was sick).

I believe age, weight, activity level and sex have a bearing on how much you can eat and still lose weight. And then there are some nebulous things like "basal metabolic rate" and other genetic influences.

If you are active, I would believe you can do 10X body weight and lose.