Long and a bit ranty. Sorry. Need to get it off my chest.
The family I married into has had problems with obesity since I've known them (17 years) but it's only in the past 10 that the chickens have started to come home to roost. As thread title says, I'm feeling sad and angry about the situation, but also worried at how it may affect my immediate family, because dd (12) is now beginning to develop a weight problem as well. Sorry for the length of this - I've been chewing this issue over during Christmas and really want to unload.
MIL - morbidly obese pretty much her whole adult life. She now has type 2 diabetes and heart problems. And arthritis. And has never fully recovered from a botched hernia operation a few years ago which was complicated by her obesity.
FIL also morbidly obese. He had a stroke a few years back while MIL was recovering from her botched surgery and was still in hospital. At 79 he weighs about 18 stone and is only barely mobile. He's incontinent and starting to become senile.
SIL morbidly obese and hypertensive. She's 50 and has just been told she will be diabetic in 2 years time. Her pancreas isn't working well at the moment but she's not yet developed diabetes proper.
BIL is obese and a smoker. He's had to retire after having a heart attack at 48.
Their youngest dc is 12 and is obese.
All in laws are lovely, lovely people, and morbidly obese SIL in particular is a beautiful person inside and out. I really love her very much.
But I've started to feel angry and intensely frustrated at how intelligent people - because not one of them is stupid - can be so fatalistic about their health and not see what's staring them in the face: that they eat way, way, way too much, and it's ruining their lives. 
Family parties involve obscene amount of food, whatever the time of year. A casual family barbecue will involve every conceivable type of meat: ribs, burgers, chicken, steak, sausages. It's expected that all the adults present will eat a couple of burgers, a couple of hot dogs, some chicken, a massive portion of lasagna, some steak, salads, garlic bread. And the children too. And at least three types of pudding. Oh, and lashings and lashings of full-fat coke, which is poured for the children into massive plastic cups. Last time DH invited the family over I asked him whether it made sense to cater for them in this way - we're either encouraging ridiculous waste (which we don't approve of and can't afford) or ridiculous overeating.
Obese SIL talks about being a bit 'naughty' and helps herself to two or three heaped tablespoons of double cream on her (massive portion of) pudding. Then has another portion afterwards, with a little tinkle of conspiratorial laughter. And we all play along. When she came back from her recent set of blood tests she told me that the nurse had said the fact that she was going to develop diabetes had nothing to do with her weight. That she'd develop it even if she was (SIL's words) 'a twiglet', because there's a family propensity towards diabetes (other SIL has had type 1 diabetes since childhood). I appreciate that there is SOME truth that she is more likely to get diabetes but surely, surely, the fact that's she's morbidly obese is an aggravating factor?
A couple of weeks ago I cracked and said to SIL that she needed to do something to protect her health, and told her I was worried about her. We discussed using internet tools like my fitness pal to log her food intake. I deliberately mentioned it because I know that the problem isn't generally that my SIL eats junk food. Actually she's an amazing cook and creates beautiful, usually healthy food. Just way, way, way too much of it. And she eats too much. I know this because I've had so many meals with her over the years. I can't tell you how many times I've had to ask her to take food off my children's plates when we've eaten at her house and she's been serving. Her response to me suggesting measuring and logging her food intake was 'oh I really couldn't be bothered with doing that - I'm just too busy'. And then in the next breath talk in a fairly non-committal way about having to do something about her weight.
It makes me want to scream.
They've done all the plans, joined all the clubs, and failed to lose weight. Or lost it and put it straight back on. Her and MIL join together, and then conspire to cheat together. They undermine each other's attempts to lose weight, and BIL is constantly sabotaging SIL's efforts too. They comfort themselves by convincing themselves that actually they eat quite healthily, and that SIL is fitter than a lot of slimmer women because she walks to work every day (about a couple of miles over the course of the day - but she doesn't do speed). And that they could be hit by a bus anyway, and that their health problems are genetic, and .... you name it. Excuses, justification, trivialising the issue day in and day out.
Also watching MIL serving absolutely MASSIVE portions to my completely sedentary 18 stone FIL. And when I say massive - I mean a big plate with food piled up to the height of about 4 inches and falling off the edge of the plate. Huge curries, corned beef hash, stews..... The sort of plate of food any normal person would serve up to a 21 year old man at the end of a day of working down a mine or building a house. I mean - this is a woman who was a nurse. And she's his carer for goodness sake. I don't think she takes any responsibility for his health problems, which are immense and are both caused and complicated by obesity, as are hers.
Anyway, so now dd is showing signs of over-eating. She's JUST within the normal BMI for her age, but is at the top end of it and edging towards being overweight. She has muffin tops, big thighs and is starting to carry a lot more weight than is healthy around her middle. She doesn't have a big frame. I can't bear the thought of a fat future for her, with all the possible health problems that can go with it, especially in a family with a tendency towards diabetes and hypertension. I try so hard to be sensible about portion sizes and serve healthy food, but she just eats and eats and eats. When she's bored. When she's tired. Because she wants to. I'm starting to suspect she see's overweight as being normal and nothing to worry about, despite the horrible fall-out she sees around her.
Should add - I'm a bit overweight myself and am trying hard to address this issue, with some success. This has happened in the last few years as I'd always been a skinny before developing thyroid problems at 43 (I'm 45 now). But I take my health and DH's health seriously and will do everything I can to stay as well as possible for as long as possible, for the sake of my children and the rest of my family, as well as for myself.
Anyway, if you've got this far, well done. 
. Am I being unreasonable to have such strong feelings about this issue. Or should I keep my big nose out of my inlaws eating habits?