Why isn’t being obese worse for your health?

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Two things that I think everyone can agree on regarding obesity is:

  1. It’s bad for your longevity
  2. It’s bad for your cardiovascular health

I don’t think these are controversial statements. Literally every doctor in America would agree with me.

That’s why it’s so strange that the literature is so mixed up on this. Let’s take the first claim, “Obesity is bad for your longevity.” If that were true, I’d expect obese people to die sooner.

Ok, cool. That’s what this paper finds in the Netherlands: obese men lose 5.8 years of life expectancy, obese women lose 7.1 years of life expectancy. I’m not sure if those are exact numbers I’d expect, but whatever.

Now let’s go to America.

In America, obese men and women (over the age of 70) live a tiny bit longer than non-obese men and women. Seriously, look at the figure.

Estimated 2-year probability of dying (confidence intervals) for obese and nonobese men and women aged 70 and older: AHEAD 1993–1998 (a black square represents obese individuals, and a white box represents nonobese individuals)
Black squares are obese, white squares are non-obese.

“But,” you say, “that’s in the elderly! That’s not a apples-to-apples comparison!”

Fine. Let’s go to 55+ in the Netherlands. And…once again, obese people live longer than normal weight people.

Ok, cool. Huh. Maybe we can then just say something like, “Obesity is bad for your longevity if you’re young, and might be good for your longevity if you’re over 55.”

And I’d agree with you. Except if you live in Australia. Obesity is bad for all ages if you live in Australia.

Well, now I’m really mixed up. At least we can say that obesity is definitely bad for your cardiovascular health, right?

Yes, for sure. Obesity is bad for your cardiovascular health. Just, uh…if you are obese, there’s no good evidence that weight loss helps your cardiovascular health.

Random effects meta-analysis of the effects of weight loss interventions on participants with a cardiovascular event. .

Oh, also, while obesity is correlated with asthma, that’s much more true for women than men. Why? No idea.


So, in conclusion, if you’re young, try to lose weight. If you’re old, maybe gain weight, unless you’re in the Netherlands or Australia.

If you’d like to improve your cardiovascular health, losing weight may not help. But, if you’re deciding whether to gain weight to improve your cardiovascular health, I would not recommend it, especially if you’re a woman.