Want to Reduce Risk of Dementia? Don’t Diet!

Debbie says:

I know I’m not alone in being more frightened of old-age dementia than any other thing that could happen to me. Everyone is different about these things, but for me, my mind is me, and without it I do not want to survive.

That fear, a lifetime of body image activism, and my hatred of junk science combine to make this the best science news possible.

The analysis of nearly two million British people, in the Lancet Diabetes & Endocrinology, showed underweight people had the highest risk. …

Dementia is one of the most pressing modern health issues. The number of patients globally is expected to treble to 135 million by 2050.

At least by basic criteria, the science is impeccable. There were 1,958,000 subjects.

Compared with people of a “healthy weight,” underweight people (BMI <20 kg/m2) had a 34% higher (95% CI 29–38) risk of dementia. Furthermore, the incidence of dementia continued to fall for every increasing BMI category, with very obese people (BMI >40 kg/m2) having a 29% lower (95% CI 22–36) dementia risk than people of a “healthy weight.” These patterns persisted throughout two decades of follow-up … [quotation marks added]

In other words, it’s not just that low BMI correlates with greater dementia, but higher BMI, well into the categories that modern medicine continues to describe as “morbidly obese,” correlates with even less dementia. The difference between having an “underweight” BMI and an “obese” BMI is a 54% (!) reduced risk of dementia. That’s a gigantic number.

Of course, BMI is and always has been a bullshit benchmark. Also of course, the scientists are thrown for a loop by their own findings, because they went in assuming that fat would fry your brain, just as their counterparts continue to insist (against evidence) that fat destroys your body. They really have to grasp for their “faith sentence” here, and what they came up with is:

… the findings were not an excuse to pile on the pounds or binge on Easter eggs.

“You can’t walk away and think it’s OK to be overweight or obese. Even if there is a protective effect, you may not live long enough to get the benefits,” he added.

We know from other large-population studies and analyses that this isn’t true.

Of course,  no one is suggesting that these results suggest that low-BMI people should try to gain weight. Just to be clear, I’m not suggesting that either; people find their own weight and everything, including dementia risk, has multiple complex factors. But you do know what they would be saying if the study had gone the way they expected!

For me, I will continue to live the way I live, to follow my doctor’s advice (“Whatever you’re doing, keep doing it”), to appreciate my fat body, and I will breathe just a little easier when fear of dementia sneaks up and ambushes me.

3 thoughts on “Want to Reduce Risk of Dementia? Don’t Diet!

  1. That’s fantastic! Also, if I haven’t said it before, thank you for “faith sentence”. You introduced me to that very valuable concept.

  2. Interesting findings. I have so little trust in the BMI measurement, however, that I wonder what this study really measured, since, as you, note, the multiple factors involved in dementia risk — many of which we may be unaware of — make it unlikely that such a study can actually measure the effect of one single variable on so large a population.

    However, I completely agree that dieting (as opposed to eating healthy food) is for most people a negative, not a positive. And I’m totally down with calming fears of dementia.

  3. I share that particular fear, Debbie. Long before I heard the dementia or Alzheimer’s disease, ever since my first real job as an aide in a nursing home, I’ve felt afraid of winding up like the elderly people there. This study makes sense and I appreciate hearing about it!

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