^^ or the takeaway is BMI is total baloney, because it does not differentiate between fat and muscle.
This topic actually first came up a few decades ago in relation to the weight of people when they died and the weight of people with terminal diseases. Guess what? People who were sicker weighed less because they were sicker. There was no causal relation between weight and disease, just a correlation between weight and how sick you were.
If indeed this work is done off BMI, then I’d expect the exact same result: BMI when you’re an adult does not mean much so a low BMI is a better indicator of illness than a mid-range BMI.
Take me. Using the NIH BMI calculator, my BMI today is 25.4, which means I’m overweight. Except any person would say I’m in the top quintile at least of men my age in physical condition. I’m not extremely muscular or anything like that but I have dense bones and little fat - and it seems very little visceral fat. If I lost all the fat on my body, I’d be somewhere above 23 BMI. And I mean down to the level where there would be no visible fat anywhere. In other words, if I actually had a low BMI, the odds would be very much in favor of one outcome: that I’d be ill.
DH has been a distance/marathon runner for the last 6 years, and has gotten very thin–“gaunt” is the word I’d use–especially since becoming vegetarian. He has become quite fragile, and is almost always injured somehow. He had surgery for a torn meniscus a couple years ago and now has developed osteoarthritis in that same knee that seems like it will force him to stop running. Stairs may even be a problem going forward. (Or, he’ll keep running and tear it up worse.)
Personally, I’m happy to be slightly overweight but still able to play beach volleyball, hike, bike, do things with the kids, clean the house, and pick things off the floor. Honestly, DH hasn’t been able to pick things off the floor for 5 years because of his constant injuries or soreness.
These medical researchers have done extensive studies on this and have dealt with examples of truly overweight and obese people, I think its not just people with a higher BMI due to muscle. I’m sure they’ve thought of that as well.
They’ve also devised studies to factor out the sick/thin factor, so that isn’t coming into play either.
@Ynotgo - Some people do get into an exercise fixation/obsession that becomes a kind of eating disorder. Do you worry that might be the case with your husband?
@doschicos Yes, he knows that it’s the endorphin rush he’s doing it for, and is upset that he can’t get the same rush from biking. If he didn’t have exercise, he would probably need some sort of medication for depression. He does tend to be obsessive about his hobbies. (She says, as she tries to stay off CC for a few hours…)
Well, exercise is cathartic @Ynotgo. Better way to get one’s happiness boost than drugs or some other less constructive crutch. And yes to CC addiction. I guess its our own form of escape/therapy. 
Perhaps a better measure of obesity and the risks thereof would be waist / height, as described at http://www.ashwell.uk.com/shapechart.htm . It is easy to measure and calculate, and directly captures the abdominal (high risk) body fat in proportion to your size.
Do not tell it to people with the family history of diabetes and HB pressure. In fact, even the young people in their mid. 20s can easily lower their BP without any medication whatsoever by just loosing weight. And I heard from many that they actually got rid of Type II diabetes simply by loosing weight. And as we have all relatives dying from diabetes on both sides of the family, mine and my H’s and we both measuring blood sugar on the regular basis (my H. is diabetic and I am not), I can tell you, that loosing weight is lowering the blood sugar even in non-diabetic person. It also definitely lowers cholesterol. So, from my personal history, I do not see any benefits in being overweight whatsoever. Of course, my family and my H’s family may be some freaks out of space who do not relate to any other human being on Earth. It is a possibility, but I would call it a very distant possibility.
Yes, if you do not have enough to carry on your bones, then osteoporosis is a real thread. However, being outside every day, walking and doing weights on a daily basis can prevent it. For the real thread to exist, you got to be skinny and also there are some genetic predisposition. So, every reasonable person can assess the risk, do not loose weight down to your bare bones and exercise reasonably.
At the end, we all die from something, dying is part of our life cycle even for the healthiest and the most normal of us.
Losing body fat specifically, not weight that may be muscle or bone, can help against type 2 diabetes. Losing muscle will probably make it worse.
I’m not well versed on diabetes issues, but how much of the improvement in diabetes is related to the weight loss vs. the change in diet related to the weight loss? I would imagine that dietary changes - less sugar and carbs, more veggies - might be more beneficial with or without weight loss, than a weight loss achieved through eating less but still eating crap.
For type 2 diabetes (either prevention or treatment), the main lifestyle changes (in no particular order) are (a) increase exercise, (b) keep body fat down, © avoid sugars and refined carbohydrates.
I saw a documentary on a unique aging study completed at a facility in California over about 15-20 years. The researchers wanted to know the common health factors shown by people who aged really well i.e. no dementia, stroke, chronic diseases. I remember the common factors well because I thought “heck I can do that!” The common factors were:
-walked at least 30-40 minutes per day (no other form of exercise seemed to have the same protective results)
-drank at least 4-7 servings of alcohol a week
-stayed active in some form of engaged work or volunteer work
-were at least 10-20 pounds over the ideal weight for their height.
Does anyone else remember seeing that?
I wish people would read the original , not just regurgitations of it by the media. Here is the Nature article cited in the link:
http://www.nature.com/news/the-big-fat-truth-1.13039
A pretty good explanation of why this study needs to be taken with a grain of salt and not as a general guide.
carachel, take a look at this:
The Survivor comparison is unfortunate, IMO.
What none of these studies addressed so far as I can see is the quality of life preceding death.
@BunsenBurner That was addressed in the original article I linked:
"Another potential explanation is that the data on people of normal weight are skewed. Researchers know that people tend to lose weight toward the end of life, but don’t always realize that they are sick. Smoking also makes people thinner and sicker. So, goes the theory, maybe researchers have inadvertently lumped mortally ill people and smokers in with healthy folk of normal weight, thus making the normal weight group look less healthy than it really is.
No matter how many ways Carnethon sliced and diced the data, the obesity paradox persisted.
There’s some evidence to back up this argument, but the studies on the issue are far from clear. The argument certainly does not seem to make the obesity paradox go away, at least according to Mercedes Carnethon, an epidemiologist at Northwestern University who has analyzed data on diabetes patients. Carnethon began by excluding patients who died within two years of diagnosis, to account for people who were already sick but didn’t know it; she still found higher mortality rates among thin people. Then she ran the data separately for smokers and non-smokers; still no difference. No matter how many ways she sliced and diced the data, the obesity paradox persisted. (Flegal also ran her data with and without smokers, and found no difference."
Personally I think quality of life preceeding death is often not great - even for people who land there simply as a result of age. My parent passed away, disease free, as is on his death certificate from failure to thrive over a period of about a year. There was nothing that could be medically done. His body simply slowed down right up until the end. Except for the last couple weeks he ate fine and was totally mentally “all there.” It was a very frustrating year for him. Now we should all be so lucky to live into our nineties and have only one bad year or we should be be so lucky to live into our nineties and go quick. Failure to thrive to me in a euphemism for what happens if you lead a good long healthy life. My other parent is also in incredibly fit, drug free health. We called them the Energizer Bunnies…they just go and go and go. Some of it’s those northern European genes, and they are, “big people” for their generation, but alot of it is simply being robust as opposed to obese and athletic right into their 90s. Being “overweight” or “large” is not the same as being obese or worse yet morbidly obese.
Excess fat behaves like an active endocrine organ in some ways, that is why it is so pro diabetic.
doschicos - not the same
The Nature paper says that one hypothesis is that age matters. A few extra pounds toward the end of life maybe beneficial, while earlier in life these same pounds are detrimental to one’s health.
If you need a little excuse for putting on a few pounds, just say we are over that hill. 
Ok, I get your distinction now, @BunsenBurner
The graph in the Nature paper shows U-shaped mortality curves based on BMI, with curves for ages 20, 30, 40, 50, 60, and 70. Only for age 60 and 70 were the lowest mortality rates at BMI > 25 (and not that much higher than 25). It is also at age 60 and 70 that the low end of the BMI-normal weight range (18.5 < BMI < 20) has a significantly higher mortality rate than the BMI-overweight range (25 < BMI < 30).
Another possible explanation is that people tend to gain fat and lose muscle as they age. At older ages, it may be that many of the BMI-normal people have very low muscle, while the BMI-overweight have retained more muscle, in addition to both groups getting fatter. I.e. it may be higher muscle weight that is more protective as one ages. Obviously, exercise helps retain muscle.