Ok, so maybe the “science” part of it is a little thin, but I found it interesting that there was the report of increased risk of death in being UNDERweight.
There are a few people I’ve met over the years in the plant based vegan community that looked like skin stretched over bone, death warmed over, that were trying to convince me that what I was looking at was the ultimate in health and I needed to be just like them. Even back then, I knew better.
I didn’t read it but in response to your comment: my cancer doc (I’m in remission) gets so pissed if I talk about losing weight stating my chances of survival are better when the cancer returns (it’s incurable) the more fat I have on me. We have a little fight about it at every 3 month visit.
His point being I’ve got a better chance of surviving being ravaged for a bit during another round of treatments if I’m fatter.
Being “overweight” is almost always better than being underweight or even normal weight for most studies, though there are always exceptions. That’s why I’m not in a race to get chiseled abs (even if I could, which I can’t).
I hear ya, Bob. My goal weight, which I’m not really all that far from at this point, (around 20 pounds or so, it varies a little,) is still considered “overweight” when just looking at a BMI chart. I come from “stocky” ancestry. We’re built kinda short and wide, including the bone structure. I’ve often remarked that I feel like if I’d been about 3 or 4 inches taller, I’d have been more “normal” in proportion. In particular, I have kinda short legs compared to the rest of me. It’s not obnoxious, but it’s noticeable to me.
BMI is a ridiculous concept in this day and age when there are so many options for evaluating body composition and the health of various adipose and muscle tissues. I consider science with BMI as a factor highly suspect.
I agree with you, Todd. It’s one reason I don’t get all that excited about it one way or the other in regards to any particular number.
When I was thinking about it, I kinda remember Ted Naiman’s graph of pretty much everything. Too much isn’t good. Too little isn’t good. Love the graph, can’t remember where it lives but I know I’ve seen it on the forums here. 
I also agree - this responsibility should not be left up to the doctor.
If your BMI is high or low, go do a DEXA scan and confirm a low visceral fat level - figure out the reason (larger than usual arms and legs, excess muscle just maybe a generally thin set of bones and flesh) you are out of the normal BMI range and determine if it a safe way to be (I’m stocky) or not (too much visceral fat). It is important to know if your BMI is normal but you are loaded with visceral fat and the doctor doesn’t have time to strip you down and use calipers. Probably unable to write a prescription to do a DEXA if your BMI is normal (which is just wonderful logic).
Make sure you can clearly explain your non-normal BMI to your doctor if asked.
Remember, they are just handed a few numbers by a nurse and have a few minutes with you. An out-of-norm BMI is a good reason for further visits and potential medication (that needs to be monitored by more visits). They are not paid by how well they reduced your visceral fat levels - they are paid to get you on something and keep you coming back.
I’ve often wondered why they lumped all adults into the one ‘healthy range’ category when they know full well that older people have better outcomes when they carry a bit extra. Found this after a quick bit of digging but I’d never seen these figures anywhere else https://www.leadingnutrition.com.au/elderlybmichanges/ This puts the healthy range at 23 - 31 for anyone over 65 years of age.
I just did a DXA two days ago. I was a little disappointed to learn that I have 17 pounds of fat that I still need to drop. I have very little visceral fat (under 2 pounds) but have been looking more height weight proportionate so was hoping I just had about 10. Oh well. I did learn that I have shrunk an inch since the last time I was measured for height so my BMI is actually higher than I thought. Again, kind of a bummer. But where they have me at healthy fat, the weight exceeds the BMI for height. Also, DXA wasn’t covered by my insurance but I was able to do it at a local university and it was $95 out of pocket, which was reasonable to get the information.
Interesting how caloric restriction impacts certain genotypes in a single based pair nucleotide polymorphism (SNP’s) DNA sequence expression in contrast to longevity and “BMI risk of death:”
16 Biomarkers May Predict Human Lifespan - GEN Genetic Engineering & Biotechnology:
“…The SIB team found that most SNPs influenced lifespan by impacting more than a single disease or risk factor—for example, through being more addicted to smoking as well as being predisposed to schizophrenia. The discovered SNPs, combined with gene expression data, allowed the researchers to identify that lower brain expression of three genes neighboring the SNPs (involved in nicotine dependence) was causally linked to increased lifespan.
“Further analysis revealed that brain expression levels of nearby genes (RBM6, SULT1A1 and CHRNA5 ) might be causally implicated in longevity. Gene expression and caloric restriction experiments in model organisms confirm[1] the conserved role for RBM6 and SULT1A1 in modulating lifespan," the authors concluded.
“These three genes could, therefore, act as biomarkers of longevity, i.e., survival beyond 85 to 100 years,” commented study co-author Johan Auwerx, Ph.D., a professor at the EPFL. “To support this hypothesis, we have shown that mice with a lower brain expression level of RBM6 lived substantially longer.”
Study co-author Marc Robinson-Rechavi, Ph.D., a SIB group leader, and professor at the University of Lausanne, concluded that “interestingly, the gene expression impact of some of these SNPs in humans is analogous to the consequence of a low-calorie diet in mice, which is known to have positive effects on lifespan.” …” …More
Footnotes:
[1] “…Four among the down-regulated genes are involved in key regulatory steps within the pentose phosphate pathway, which has been previously associated with lifespan extension in Drosophila. Combined analysis of dietary switch with whole-genome time-course profiling can identify transcriptional responses that are closely associated with and perhaps causal to longevity assurance conferred by dietary restriction. …” - Dietary switch reveals fast coordinated gene expression changes in Drosophila melanogaster
I’ve read this before but think bone size matters as well. For me to get to 23, that would mean I would have to gain 20 pounds. It was only by losing the 20 pounds on keto that I was able to normalize my blood work and glucose.
I also have a low personal fat threshold & need to stay small to keep my blood sugar in check - I’m just going to assume that the link I posted doesn’t apply to you & me. I’ve also had to quit worrying that my LDL is too low 