I recently lost 30 pounds with NO exercise at all. In fact when I started I was very sick and barely dragging myself through the day.

I would be truthful but diplomatic: if he's never been overweight, especially as a woman, he's got no experience to offer. I would also point out previous attempts at following conventional advice (like his) has gotten you worse, not better.

It's time for you to choose your way.

I went down to Atkins Induction levels, and below! for amazing health results. That's what the weight loss is really about: my body is working better, and I am giving it better fuel.