It's about 1800 KCal, give or take, on a day of sedentary office work. I'm deeply familiar with it after years of calorie tracking. My grocery shopping and meals, most cooked from scratch on a daily basis, are designed around it to keep at a stable weight.

If what you actually mean to say is "you're wrong, there's no way you could eat like that", the response is "give me nothing but heads of lettuce with salt and pepper, and there are days when I could still continue eating them the entire day whenever my stomach isn't literally full".