"But the real reason [married people gain weight] is moral hazard, or the tendency to take more risks and behave more irresponsibly when there are no consequences." I'd never equated being overweight as behaving irresponsibly. If everyone thought this way, would we all be thinner? If my spouse can't nag me to lose weight (see #1), is there anything she could do to encourage it, or is it all on me?
Recent research shows that obesity is caused more by the types of food that we eat than the amount that we eat. (And the types of food that surround us these days are increasingly the wrong kinds). I would suggest that you and your wife do some research into obesity/nutrition and form a meal plan together. It is much easier to eat the right foods when you're doing it together. It's also fun to cook together. At least…
A blog post I wrote illustrating one of his deceptions: http://crazybear.posterous.com/how-1-graph-reveals-what-3000...