Parents of overweight children don't know their children are overweight

Such abstract thinking just doesn't come naturally. We are incredibly biased here because our jobs often require little else except abstract thinking. This is massively atypical.

From the study: A person's chances of becoming obese increased by 57% (95% confidence interval [CI], 6 to 123) if he or she had a friend who became obese in a given interval.[0]

One of the authors is quoted as saying: “You change your idea of what is an acceptable body type by looking at the people around you,” Dr. Christakis said.[1]

[0]http://www.nejm.org/doi/full/10.1056/NEJMsa066082 [1]http://www.nytimes.com/2007/07/25/health/25cnd-fat.html

  "Respondents were grouped by child body mass index (BMI)
   percentile (<5th, 5–84th, 85–94th [at risk for overweight
  (AROW)], and ≥95th [overweight])."

I've always been very conscious of my child's weight, because I don't want her dealing with the same feelings of shame, discomfort, lack of energy, etc. that I went through as a kid, or to face the medical problems later in life that I'm now working hard to avoid. This is, for me, a Really Big Deal. Being overweight sucks. I want better for my kid.

If anything, having a kid has helped me, because teaching healthy lifestyle and eating habits by example is far better than telling her one thing and doing something totally different, myself.

On the other hand, I have an overweight friend with a 100+lb, average height, 9yr olds who will argue all day that the kid "isn't fat."

The first link when googling for "lifespan by bmi" is:

http://wehrintheworld.blogspot.com/2009/05/bmi-and-life-expe...

Which cites two metareviews. The first is a collaboration between the UK Medical Research Council, several British organizations including one out of Oxford, and the US National Institute on Aging (which is under the NIH umbrella). It was published in _The Lancet_ (Impact factor: 33). I will quote the quoted part from said blogpost:

> BMI is in itself a strong predictor of overall mortality both above and below the apparent optimum of about 22·5–25 kg/m2. The progressive excess mortality above this range is due mainly to vascular disease and is probably largely causal. At 30–35 kg/m2, median survival is reduced by 2–4 years; at 40–45 kg/m2, it is reduced by 8–10 years (which is comparable with the effects of smoking). The definite excess mortality below 22·5 kg/m2 is due mainly to smoking-related diseases, and is not fully explained.

While I found a few studies that didn't find a correlation (including one in AMA), I can't actually find an academic source for the claim that people with a BMI of 25-30 have the longest lifespan and see lots of claims that the optimal BMI is in the low 20s. Do you have any citations handy?

Denial's everywhere, I guess.

Assuming that the claim is true that people with a BMI of 25-30 live longer than any other BMI range, how is believing that claim denial? Or in other words, what do you think that poster is denying?

So even sizes in stores work to make people feel they're ok. 1X isn't "extra large" It's "woman sized". WTF?

There are communities where that's considered a good thing. I recall an episode of 3rd Rock from the Sun where one character was looking for a dress, and was dismayed to find that the standard sizes were designed to make women fill overweight and inadequate (it turned out that the store had been taken over by impossibly-thin supermodel aliens, IIRC).

If the trade-off is between being happy and size X, but dying early, or unhappy and size X, and dying early, which is better? How do you convince people to be happy about where they are by being happy about where they're going?

Your logic is broken (or you do not present all of it) in a different way: a quick google gives me the impression that for kids in the USA, the 75th percentile is about the edge case, but you need extra data to convert percentiles to 'being too heavy'. In the extreme, if everybody is overweight, even the lightest percent of kids will be overweight).