My husband and I have both been obese since pretty early on in our marriage (we used to be extremely bad "enablers" of each others' food consumption) and we each started going to the gym last May. We're a perfect illustration of how important eating habits are to weight loss; while I have lost 85+ pounds in the last year, his weight has stayed the same, although his body shape has changed somewhat (and he's got some NICE muscles! ).
Anyway, I basically had gotten used to the differences in the way we eat, not pointing them out but instead trying to model healthier habits and their results (and planning healthier meals at home). Something seems to have *clicked* with him in recent days, however, because he has started changing the way he eats in some fairly dramatic ways. As a result, he's lost 8 pounds since two weeks ago! I still don't mention it too much (it's not his style to talk about it in any major way) but I'm really thrilled that he's making this effort. I think he will only get more motivated when he starts seeing more tangible results (like the pants-o-meter or comments from others).
The only [minor] downside is that, even with a reduced calorie diet, he can still eat a whole lot more calories than I can and still lose. This means we can eat the same thing and result in a "good day" for him and a "bad day" for me. As long as I'm constantly aware of that, I can continue to adjust my intake.
Anyway, just wanted to share. If anybody else has been through something similar or just has thoughts, I'd love to hear what you have to say. In the meantime, wish us luck... I really hope this trend continues!