Comment from a former HG+ anorexic perfectionist (not the only one on the board by a long shot, I'll be bound...): it may not be a popular view but I suspect there is no way you can talk about weight loss, food restriction, etc. without it being a danger to your intelligent perfectionist children. However you surround it with talk about wanting to be healthy, what you're drawing attention to is the fact that, because in earlier times you ate more than your bodies needed, now you need to eat less than you would like to, in order to get back to a good state. For an intelligent perfectionist child to decide to be very careful never to become overweight in the first place, and to do that by exercising careful control over what she eats, is unsurprising; and that level of concern about and control over food intake is in itself dangerous. (You can say "you just listen to your body, you're fine" but if you're simultaneously noticeably doing something different, this is a bit "don't think about a pink elephant".)
[And be careful about complacency: I remember, as a young child surrounded by dieting, eating what I was given and saying the right things, but deciding that, once I had enough autonomy over my eating, I would put clear blue water between me and being fat. In my teens I got the autonomy and did just that. When I was 5, my parents probably thought there was no problem, but there was. Being very good at delayed gratification has its drawbacks.]
My advice would be: imagine you're at a healthy weight and in a healthy lifestyle, and talk as you would talk if that were so. Don't mention weight. If you're eating less than you would then, fine, but do so without comment. Don't mention calories. And of course, exercise and encourage exercise, but don't connect this with weight.
