[PuppyTailWags]

It seems that despite increased risk of diabetes, being slightly overweight actually decreases all-cause mortality and being grade 1 obese doesn't affect all-cause mortality. I heard of this through a podcast and I'm not super educated, but it seems to me that the relationship of weight and health is more complicated, since I agree that increasing risk of heart disease, diabetes, etc. is bad. It just doesn't seem to bear out in actually killing a person. Maybe it decreases their quality of life drastically instead?

https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4855514/

[adrianN]

I wonder whether that is true for all age groups. In very old patients, being somewhat overweight can act as an important energy reserve that allows the patient to survive an illness or a hospital visit. Younger patients generally are more robust, I assume they benefit less from a couple of extra kilos of fat.

[PuppyTailWags]

The study accounts for age and shows the phenomenon is consistent across multiple age ranges.

[DontchaKnowit]

Yes THANK YOU. This is why it is infuriating to me that elementary/middle school students are still being graded on their BMI in gym class and taught to maintain a "good" BMI. With my body composition, I would be absolutely emaciated if I was on the lower end of the "healthy" BMI range. As it is I am bordering on obese, which if you saw me in person would be completely preposterous. The BMI itself is a pretty useless metric of body fat, and body fat is a pretty useless metric for health.

[eternityforest]

Why is this such a hard question? You would think a question as ubiquitous as "What should I eat?" would have more consensus.

Some studies show extra mortality in normal to underweight people, including from common causes relevant to average people, but there's also a ton of work on calorie restriction?

Is low BMI dangerous, or does it just commonly go along with a lifestyle that might lead to injuries and rhabdomyolysis and a case of diarrhoea in a place without hospitals?

It would be interesting to see adventurousness treated as a separate category for controls.

In the past there was no fridge, people stored their own energy, and there was no pepper spray and cops and forklifts, exercise programs had the extra constraint of physical activity being directly needed to survive.

What amount and type of activity should a modern person who has reason to believe they'll probably never be in a serious fair fight with no weapons or need to walk 3 days to get help do?

How much should someone eat when they do not ever plan to drink untreated water or go somewhere away from medical help if they catch some parasite that causes rapid weight loss?

Is the ideal profile of nutrition changed for someone who will not be exposed to woodsmoke, bacterial illness, etc?

And then furthermore, if higher BMI isn't helpful by itself, what should people who ARE in poverty or otherwise exposed to more stresses do?

Is there a subgroup that needs a metabolic reserve? Should those people eat less to save money and be able to DoorDash if needed and have external reserves like people without poverty or adventurousness?

Or is there a real independent benefit to some level of fat?

[stnmtn]

̶R̶e̶a̶d̶i̶n̶g̶ ̶t̶h̶i̶s̶ ̶s̶t̶u̶d̶y̶,̶ ̶I̶ ̶b̶e̶l̶i̶e̶v̶e̶ ̶y̶o̶u̶ ̶a̶r̶e̶ ̶m̶i̶s̶i̶n̶t̶e̶r̶p̶r̶e̶t̶i̶n̶g̶ ̶t̶h̶e̶ ̶r̶e̶s̶u̶l̶t̶s̶.̶ ̶I̶t̶ ̶s̶a̶y̶s̶ ̶n̶o̶t̶h̶i̶n̶g̶ ̶a̶b̶o̶u̶t̶ ̶i̶f̶ ̶b̶e̶i̶n̶g̶ ̶o̶v̶e̶r̶w̶e̶i̶g̶h̶t̶ ̶d̶e̶c̶r̶e̶a̶s̶e̶s̶ ̶a̶l̶l̶-̶c̶a̶u̶s̶e̶ ̶m̶o̶r̶t̶a̶l̶i̶t̶y̶ ̶r̶e̶l̶a̶t̶i̶v̶e̶ ̶t̶o̶ ̶n̶o̶r̶m̶a̶l̶ ̶w̶e̶i̶g̶h̶t̶.̶ ̶I̶t̶ ̶o̶n̶l̶y̶ ̶s̶a̶y̶s̶ ̶b̶e̶i̶n̶g̶ ̶o̶v̶e̶r̶w̶e̶i̶g̶h̶t̶ ̶d̶e̶c̶r̶e̶a̶s̶e̶s̶ ̶a̶l̶l̶-̶c̶a̶u̶s̶e̶ ̶m̶o̶r̶t̶a̶l̶i̶t̶y̶ ̶r̶e̶l̶a̶t̶i̶v̶e̶ ̶t̶o̶ ̶o̶b̶e̶s̶i̶t̶y̶.̶ ̶ ̶T̶h̶a̶t̶ ̶i̶s̶ ̶h̶o̶w̶ ̶I̶ ̶r̶e̶a̶d̶ ̶i̶t̶ ̶a̶t̶ ̶l̶e̶a̶s̶t̶,̶ ̶I̶ ̶c̶a̶n̶'̶t̶ ̶f̶i̶n̶d̶ ̶a̶ ̶b̶a̶s̶e̶l̶i̶n̶e̶ ̶f̶o̶r̶ ̶t̶h̶e̶ ̶H̶R̶ ̶o̶f̶ ̶a̶ ̶n̶o̶r̶m̶a̶l̶ ̶w̶e̶i̶g̶h̶t̶ ̶i̶n̶ ̶t̶h̶e̶ ̶s̶t̶u̶d̶y̶ ̶l̶i̶n̶k̶e̶d̶.̶

edit: this is wrong, see reply below

[PuppyTailWags]

The article explicitly compares overweight, grade 1 obesity, grade 2 & 3 obesity together, obesity generally, relative to normal weight.

> Random-effects summary all-cause mortality HRs for overweight (BMI of 25–<30), obesity (BMI of ≥30), grade 1 obesity (BMI of 30–<35), and grades 2 and 3 obesity (BMI of ≥35) were calculated relative to normal weight (BMI of 18.5–<25).

[stnmtn]

Great point, I completely misread that. Edited my original comment!

[PuppyTailWags]

Yeah I had to read this a few times too! I was totally baffled by having 3 categories for obesity, but one of the categories is grade 2 & 3 categories together, and one of the categories is grade 1, 2, & 3 together.

[thisismyswamp]

I think the catch with this study is that BMI is different from muscle mass and fat mass.

Higher BMI can simply mean more athletic.

I wish we could tell!