100% agree with this.
One thing I notice about people who fail diets/loosing weight, is they try one that is unsustainable in the long run. It should be a whole lifestyle change with the goal to eat better your whole life. From my experience it seems Women are the worst for this, they will juice or only eat carrot sticks for a month end up loosing a stone but a few weeks later are back to eating 4 biscuits with their tea 5 times a day and buying loads of sweets.
It is the instant gratification thing I suspect... people try to lose weight in short amounts of time/want to see results now - try some faddy diet that involves starving themselves or eating just soup or some other nonsense... and they perhaps do see some immediate results, though perhaps just losing water weight.
In reality it is perhaps a lifestyle change that is needed, not just a 'special diet' that is followed for a bit and seen as a chore. Most of the obesity crisis is just down to the extra rubbish we eat that didn't used to be a part of life a couple of generations ago... it isn't like out grandparent's generation went around feeling hungry all the time... they just didn't have lots of cans/bottles of sugary water in their fridge, didn't have fried chicken shops and kebab houses on every high street, didn't have McDonalds, didn't have big multipacks of crips, freezer food from Iceland etc.. etc..etc..
If people are really struggling then just don't buy junk, make things from scratch, eat proper meals/stop snacking and you shouldn't feel hungry... no reason why you can't have a big bowl of porridge in the morning, decent sized lunch and some traditional dinner in the evening with plenty of veg etc.. just cutting out all the **** and eating your greens, cooking proper meals etc.. would do the trick for most people - no one needs cans of coke and bags of crisps in their house.
I've got to be super careful about some of the things I eat, but for people without long term health conditions it is a hell of a lot simpler to eat healthily.