Thing is... whether fat is unhealthy or not, and on balance I would say it wasn't a great idea to get fat, the OP has asked in the title of her thread how to 'deal' with her DH's weight gain. I've been fat and I've been thin, and I know what it is like to have someone in the family 'deal' with my weight problem [FYI Mother - all I got was food hang-ups and body image problems, for life]
There is absolutely nothing the OP can do to make her DH lose weight. As is said very often on these boards, you cannot change someone - you just can't. They have to want to make changes themselves, whether they are an abuser, whether they are an addict, an obssessive cleaner or hoarder or whatever. They have to do it themselves and find the key to it themselves.
OP, I suspect, can police the biscuit tin all she likes and it will be a pointless, hopeless and depressing task.
OP - you may care that he is fat, he might not care. Or he might care a lot. Again, I don't think these things are of much relevance. If you pressurise him to lose weight, my guess is that he will feel attacked and unhappy. If you start monitoring what he puts in his mouth he may feel really resentful and cross and, most importantly, quite determined to spike your guns... which would entail more overeating and general subversive behaviour like hiding his eating, so he'd be stuffing himself when he is not in the house and out of reach of the food-stasi.
Be pragmatic. If he raises the subject himself, that's fine... talk to him, say you will support him if he chooses a new exercise regime or eating programme. But please don't initiate this yourself. If he's already concerned, he will articulate it. If he is not already concerned about his weight, then you raising it will not help. He is the one living in his body - so of course he knows he has put on weight. I would think that he would want to do something about it. This is an emotive issue. He is a person, not a concept. Obesity is a huge problem... if there was a simple thing like confronting a fat person and telling them they've got to cut down then we'd all be thin by now.