I've always heard this and accepted it as a hard and fast rule but now that I'm older I wonder about it. Calculators say that at my age and exercise level I should eat 1271 calories to lose one pound a week -- 721 to lose 2 pounds a week. I find the one pound a week thing very slow and frustrating, particularly if I plateau or actually gain that week.
I've always heard you must have 1200 cals per day to meet all your nutritional needs, but I'm considering trying 1000 a day. Surely, my nutritional needs as a 70 year-old sedentary woman are not the same as when I was a young active mother.
Thoughts?

I'm not a big calorie counter but I would guess normal pound a week weight loss for me is at 2200 calories a day. Can you build up some lean muscle with pilates or exercise bands? You might gain a pound or two initially but it should up your metabolism.