To wonder why people don’t look after themselves

Two thirds of adults in England are obese or overweight. It would make as much sense to ask what is different about the other one third.

I would recommend self-referring for CBT if he can. There’s a clear behaviour which needs to change but he needs help with the thoughts and feelings making it too hard for him to do it.

You do seem to know in your husband's case. Issues rooted in childhood trauma and reliance on strategies that don't work such procrastination and as buying self help books then not using them rather than accessing therapy.

People know being overweight isn't good for them. The reasons can be very complex.

I was never enormous (size 18 on a largish, tallish frame at my biggest). It was a huge weight gain from epilepsy meds. Some people treated me as though I was lazy, ignorant etc etc. It went on fast so I knew what the reason for the difference was. It was an eye opener. I've had to lose weight for this reason about 3 times now. Luckily for me I enjoy healthy food and hyper focus on things like step count and my cal counter not my weight but it's hard. Mine is quite a simple cause but a lot of self esteem, value judgement and motivation issues fed in and each time there would be false starts before I made that big kick off into a plan that stuck.

If he's addicted to food, then it's not an easy thing to break. Also once you're big you actually feel hungry a lot and your body starts to demand such a high number of calories. So he needs to shrink his stomach, slowly but surely.
I guess he could try weight loss jabs?
Could you overhaul your weekly shop together to take out all the crap, and replace with healthier snacks? It's very hard for some people to drop weight without help. I hope things improve.

It's got nothing to do with willpower, it sounds as though he eats to push down his feelings.

He feels something painful or difficult and his immediate reaction is to eat in order to feel relief. You say he's been through a lot of trauma and it sounds as though he's done nothing to address that trauma.

Mindfulness might be helpful as it helps you stop sleepwalking. It trains you to catch those moments before you reach for food.

Overeaters Anonymous might also be helpful, he can join a group to discuss experiences and find ways to move forward.

If he's depressed or suffering from anxiety or eating is a compulsion, medication might help. He'd need to see his Dr to discuss. Having blood tests might rule out anything physical contributing to it.

He could find a therapist that specialises in adverse childhood experiences and eating disorders. BACP would be a good place to start.

Indeed.
There are many people in your husband’s situation OP. If it was as simple as “just do it”, they obviously would. There’s something blocking him from doing what he needs to do. It’s possible that therapy could help, but he obviously can’t do it on his own.
It’s a bit like saying “why don’t people with depression just cheer up?” They are just not able to, that’s the whole problem.

Get him on the Mounjaro OP. Then he can try and work through his trauma without the constant reminder he's fat and therefore useless

I find this topic fascinating. I wonder this all the time. I guess if it was easy everyone would be a healthy weight and exercise and generally try and control the controllables. But so many don't. I think it's a mix of motivation and general mindset but even people with massive health problems persist with unhealthy lifestyles. I guess you need a strong reason why. Maybe talking to him about being around in the long term for his children would give him his reason why. 🙏🏻It's sad really isn't it. Being unwell is crap so you'd think he'd try and avoid it

I think your last paragraph gives the why.

How do you feel about helping? E.g not buying junk, keeping on top of him, encouraging him / beating him with a stick? Some people need a cheerleader / coach to get them through the start part, once habits are formed it can be easier.

Will power is flaky imo, I used to have crap willpower. I ended up watching a few motivational videos and they all said you need discipline not motivation, because motivation waxes and wanes but discipline is constant.

Yeah no great mystery there.

You, on the other hand OP, are more of a worry. Shocking failure of empathy which is way worse for society than fatness.

This is too simplistic. It's not about wants.

But I agree about 'why he doesn't care' there is a reason but I'm not sure it can always be identified.

I don't know.

I am your husband in this situation - it is complex, I know people trying to encourage me just makes it harder to do something about it. No one else can make me feel worse about myself than I do.

And it is all within my power to change - I don't know why I can't. It is a miserable place to be, even if no one else realise how miserable it is.

He would do it if he cared. Same as with addicts, if they wanted to, they would pull out the stops to seek help. He has to hit his own rock bottom. He needs to find out why he doesn't care.

I also struggle to understand this, particularly when someone has relatively young children. It’s frustrating when you know how much better they would feel if they got fit. I speak as someone who hates exercise and is horribly greedy but work very hard to stay slim, fit and healthy.

He has a very, very traumatic childhood and he says he slipped into this attitude of putting things over whilst he was at school and its effect him his whole life

You've just answered your own question