Dieting and the obesity paradox
It’s a real paradox, one I’d not heard of before, and it shows once again how little we really know about disease and weight and health.
Type 2 (adult onset) diabetes, which is more common in the overweight, also occurs in normal weight people, who constitute about 20% of the population that suffers from the disease. But the odd thing is that normal weight Type 2 diabetics seem to do worse than the overweight ones in terms of mortality, and no one has a clue why:
In the study…researchers reviewed data involving more than 2,500 people with Type 2 diabetes, some of whom were followed for decades.The scientists found that those who were of normal weight around the time of their diagnoses were twice as likely to die during the study period, compared with those who were overweight or obese.
The researchers could not explain why having a greater body mass index, or B.M.I., might protect someone with diabetes. But they did point out that some doctors may be prone to treating thin diabetics differently from their obese counterparts, and may be less likely to push them to make diet and exercise changes that could improve their survival.
That explanation is just a guess. I have a different guess, which is that since overweight can bring on Type 2 diabetes in the genetically susceptible, those who develop it when they’re not overweight probably have a more severe form of the disease in the first place.
But that’s not all. The obesity paradox is not limited to Type 2 diabetes:
The findings also provide evidence that patients with Type 2 diabetes may display what researchers call the obesity paradox, the observation that people with certain chronic diseases tend to have lower mortality rates if they carry excess pounds. The phenomenon has been documented previously in people with heart failure, hypertension and kidney disease.
Yep—there’s an awful lot we don’t know.
Aww come on, Neo. The human body is incredibly simple and easy to understand. Why, if we know now that CO2 is the one and only driver of the climate, then surely we also understand that being overweight is the only condition that affects lifespan and disease. /sarc off
BTW, I am forever dealing with pre-meds who insist that since the computer fit a straight line to data with an r^2 of .9 then that MUST be the correct relation. To be a physician requires a mind that can absorb and catalog vast amounts of known data. And then correlate that data to a list of symptoms. But synthesizing new data is the thing that usually throws them for a loop. Which is why physics is the bane (err Bain?) of pre-meds.
I doubt that the difference in outcomes has anything at all to do with treatment differences. Obesity is a defense mechanism against high blood sugar. In the years before diagnosis, fat Type 2s are able to shunt excess glucose into the fat tissue, maintaining relatively normal blood sugar levels most of the time but at the cost of weight gain. It’s only when the fat cells are no longer capable of further growth that fat Type 2s become overtly diabetic, with persistently high blood glucose levels.
Thin Type 2s don’t have that option. They have a physiology that for whatever reason resists fattening. Perhaps they experience higher average sugars for a longer period before diagnosis than do fat Type 2s.
By the way, hypertension, heart disease and kidney disease are all among the sequelae of impaired glycemic control. I don’t think there’s really much of a paradox or mystery here.
The paradox (I’m reluctant to simply call it the obesity paradox) relates to almost all illnesses. That is the best health outcomes for all ages with alomst all illnesses happen when the patient is at a BMI of about 27.5. 27.5 is not obese. The rational for the name “obesity paradox” is because people with a BMI of 30-35 are healthier then people with a BMI of 15-20. Those two BMI ranges are on equally opposite sides of the BMI spectrum. This paradox also applies to the more normal ranges, i.e. people with a BMI between 25-30 have better health outcomes then people with a BMI between 20-25. When you look at the data this way it is more reasonable and intuitively acceptable then the mental picture of “obesity” being “healthful”. It is true that “obesity” is healthier then the malnurished BMI range of 15-20 but not necessarily healthier then the thin BMI range of 20-25.
My sister, who’s been an ER nurse for over 30 years, says she sees far more skinny patients for medical emergencies (as opposed to injuries) than she does fat ones. Being morbidly obese is no benefit to health, but apparently being too thin isn’t, either. Maybe being just a bit heavier than the charts say you should be is the sweet spot.
There’s a towering amount of hubris in all sorts of sciences. I’ve gotten increasingly disgusted with it the older I’ve gotten.
It’s rampant, of course, in climate science, where the word science has to be used advisedly. But it’s present in paleoanthropology, medicine, etc., etc.
We just don’t know everything about everything, and because we know a little doesn’t mean we know a lot. But it seems to make some people more comfortable to believe they know a lot than to admit they know little.
It was always very noticeable in paleonthropology where, over the years, sweeping conclusions beyond all reason have been drawn from a handful of bones. Just yesterday I was reading an article about claims that there are two new human-related ancestors but other anthropologists were criticizing those conclusions for just the reason I stated. The only evidence is a handful of bones that don’t lend themselves to a clearcut conclusion.
Climate science, as I said, is rotten with this sort of declarative assertion, as well. The temptation to leap from “this is the best information we’ve got” (however paltry and incomplete) to “this must therefore be absolutely true” must be overwhelming to weaker minds. Uncertainty is not for the faint of heart, I suppose.
And medicine is just another very complex area where certainty is the hobgoblin of little minds. Take a problem with 1200 unknowns and solve for x. Good luck.
“In the beginning, I did not expect plate tectonics, but the more I studied it, the more I realized Mars is so different from what other scientists anticipated,” Yin said. “I saw that the idea that it is just a big crack that opened up is incorrect. It is really a plate boundary, with horizontal motion. That is kind of shocking, but the evidence is quite clear.”
link
The paradox is similar to one in dementia. So-called ‘early onset’ Alzheimer’s disease is more deadly and leads to faster cognitive decline than so called ‘late onset’ AD. Basically, the younger you are when you get diagnosed, the worse off you will be (to simplify greatly).