It is difficult to determine if researchers are measuring the effect of caffeine itself or the effect of individuals taking caffeine to recover from the effects of caffeine withdrawal. This is a common weakness in studies that show purported benefits to caffeine consumption[1,2,3].
Anecdotally as someone who quit caffeine entirely about a year ago, the effects of caffeine withdrawal seemed to last much longer than the 24 hour period that many studies ask participants to abstain for.
24 hours, seriously? In my experience from quitting caffeine cold turkey many times, caffeine detox takes 2-3 weeks. The first 24 hours is relatively easy, on days 2-3 the headache and extreme lethargy really sets in. The worst clears up in 7-10 days.
I think the only meaningful way to run the study is to compare people who are completely free of caffeine, versus people who are steady state a certain level of caffeine per day. Either two different groups, or the same group separated by a month.
This research assumption is right in line with how society ignores caffeine as a non-drug. When asked what drugs I'm taking, I've told doctors things like "500mg caffeine" and they looked at me like I had two heads. Or my aunt who has trouble sleeping to the point of being prescribed benzos, but still has coffee at 5PM. Apparently it's all just "drinking coffee" and not doing a psychoactive drug, because "drugs" are "bad".
or the effect of individuals taking caffeine to recover from the effects of caffeine withdrawal
After decades of personal experimentation with caffeine, this is my conclusion personally. I get about two weeks of a boost if I go from 0 caffeine consumption to moderate caffeine consumption. After that two week period, I am simply consuming caffeine to feel normal.
I think the only meaningful way to run the study is to compare people who are completely free of caffeine, versus people who are steady state a certain level of caffeine per day. Either two different groups, or the same group separated by a month.
This research assumption is right in line with how society ignores caffeine as a non-drug. When asked what drugs I'm taking, I've told doctors things like "500mg caffeine" and they looked at me like I had two heads. Or my aunt who has trouble sleeping to the point of being prescribed benzos, but still has coffee at 5PM. Apparently it's all just "drinking coffee" and not doing a psychoactive drug, because "drugs" are "bad".