| I'm a physician. There are a lot of problems with the original article. The body is excellent at maintaining glucose concentration in the blood with food or with days of fasting. Glucose is the primary short-term energy source for most cells. The brain's energy requirements vary very little with "thinking" despite the assertions to the contrary in the introduction of this article. PET works by noting the slight transient increases in some brain regions with active thought, but moments later (as that 20% of blood flow goes swishing through the brain) more glucose is available. Meanwhile you are digesting sugars and carbohydrates, and your liver is supplying most of your fresh glucose if you are a fasting adult. Already, before reading the article, I have a low pre-test probability of their hypothesis being true, so they need extraordinarily strong evidence to make their point. Instead, there is a very weak chain of experiments, poorly reported, with borderline statistical significance. Poor charts, no tabulated results, just terrible. The primary problem is that they assert that glucose fluctuations occur due to the exercise of willpower. They try and fail to show this with their first experiment. However, their "results and discussion" combined section shows that their control group before and after glucose were very close to their post-intervention group glucose. p327 para 1. This shows how weak their statistics and data are, and from this point, you can throw the whole study in the trash. |
Suppose I made the argument "car crashes rely upon momentum":
- car crashes is a terse signifier; a high-level recognition of something that no doubt relies upon low-level phenomena
- momentum is a physical, and therefore, low-level, phenomenon
No one would say I said anything useful. They would say "well duh but why were they driving towards where they drove? were they reading a text? were they drunk? were they even to blame when they crashed? was the car fully-functional? what were the weather conditions like? how much experience driving had they had? how old were they? how good was their vision?" etc..
More or less this is what is going on with, at least, the headline implies:
- self control: high level subjective phenomenon (who is to say that every person has self-control via non-dissimilar mechanisms??)
relies upon
- glucose: a correlate. Correlates are mostly useless and used to fool people, even if r > 0, and even if r=~1. Correlation more often indicates that there is a combination of excitement and merely-coincidental yet spurious non-causality in >99.99% of measurements.
I don't blame people for wanting there to be a simple, chemiological explanation for things that are very important to their existence. But I do blame the people who are responsible for preemptively jumping the gun and broadcasting the suggestion that these questions have been answered, especially because they are reporting that it was solved via something as vulgarly facile as in vivo molar concentration of near-universal molecule
Even if it is unlikely that the claim is true in a fundamental and meaningful and not-merely-correlative sense, after so many decades of prior investigators having approached this obvious hypothesis..