Another concern calories is that this varies over the person's lifespan.

The same woman (say, me!) who could eat like a horse as a child and young
teen may find herself with a lower ideal calorie intake in her 30s and yet
another (lower) level in her 50s. The metabolism definitely adjusts
downward as most of us age. I have found that menopause is putting my
brakes on my metabolism in a dramatic way. :-(

- Anne