If a spouse begins to gain a lot of weight should the other say or do anything different?

I’ll start off with a (sort of) sexist example. Let’s say the woman begins eating a lot more than usual and the man notices the obvious. No medical problem is involved. The gain is purely from eating more at every meal and a snack at night. Is there a point where he should say something? Should he pretend he does not notice? Should he hide or discard the cookies and ice cream?
On one hand, she is an adult and is clearly responsible for her own actions. On the other hand, he can be supportive by suggesting joint exercise or cooking healthy meals.
For those who say she is an adult and is making her own choices, would you leave crack out in front of a crack addict? Would you drink or leave alcohol in front of an alcoholic?
What if the added weight is affecting the couple’s life style? How is this different from the man spending their money on extravagant purchases without consulting her?

I put this in Social so have fun with it.
Although, I’d like some honest responses, too – especially from men or women in relationships who gained weight to excess.