I'd like to suggest an alternative explanation for "tolerance" to caffeine/coffee other than improvement of the liver (or at least a partial explanation that works in conjunction with the liver improvement). It is informed by the idea that exercise likewise increases metabolism temporarily.
Exercising on a fasted, empty stomach causes up-regulation or adaptations improving ability to use stored (and probably acutely ingested) fat utilization for energy (along with increased glucose utilization ability). But this takes time. Similarly, the purported "~3 days adaptation"(from Haiduts thread) and even lasting changes can be seen as a lasting increased ability to use stored fat as energy, similarly to how exercise causes this adaptation.
Another further idea: This adaptation (resulting from increasing metabolism) gradually results in less stress hormones needed to be released as the body and cells becomes more efficient at releasing stored fat quickly, as well as all sorts of processes involved. Likewise, I'm sure increasing fitness involves improvements in the speed at which the body can mobilize resources, both glucose and fats.
Another adaptation may be an increased sensitivity to adrenalin and other hormones. I've read before about how fasting occasionally increases sensitivity to adrenaline, in a good way, similar to the concept of insulin sensitivity. Perhaps this allows the body to achieve the results it wants with less stress hormone released? i.e. by creating surges/spikes in adrenalin and cortisol, by stressful, metabolism stimulating events like exercise or caffeine ingestion, the body adapts and responds better in the future (such as with tighter feedback mechanisms, keeping stress hormones at useful rather than excessive levels, and reducing them more quickly). Smaller amounts cortisol/adrenalin will be needed to release needed amino acids for gluconeogenesis, resulting in less cortisol causing problems elsewhere.
This could all be instructive as to how preventative stress hormone spiking could actually be. Hormetic effects, from acute stressors, are anti-stress effects, and should be looked into more here.
Another consideration: The Fat Burning Zone
In light exercise, moderate to slow cardio, the body uses both fat and carbs, and as intensity increases, the ratio of carbs to fat used increases, but fat is still basically always used, and higher intensity results in higher total calories used over same time span, but one realization in the past few years that dispelled myth that fat burning zone burnt more total fat was that in both cases, moderate and high intensity, basically the same level of fat is burnt. The higher intensity also results in alot of post exercise calorie burning, which will certainly be a lot of fat burning if your only eating carbs and spiking/crashing blood sugar by not having fiber or fat with it.
The insight from the "Fat Burning Zone" is that fat is always being used for energy in all activities, on a continuum from light to vigorous, from sitting in a chair (burns more calories than laying down) to sprinting away from a raging grizzly bear, and I suspect anything that increases metabolism will instantly encourage the body to increase efficiency of both glucose and fat utilization (in more ways than cellular metabolism), and, will always do such. In this light, Caffeine, and any other metabolism booster, can be seen as a surrogates for exercise benefits, thus explaining its health protective and longevity benefits in those who use it daily, matching the humans and all animals natural "daily" highly physically active lifestyle.
Since caffeine strongly increases metabolism, like exercise does, having just carbs with your caffeine probably isn't going to prevent it from increasing fat utilization, and probably hasn't for most who have tried it here. To avoid releasing stored fat, one would do best to have fat with the caffeine. (But those using it to clear liver fat may do best to take caffeine before meals, so it reaches highest concentrations. Also on this note: It is well known in bodybuilding circles that taking metabolic boosters for fat burning "cuts" become much more effective if you take them while intermittent fasting. I suspect this could also apply to clearing liver fat)
So having just carbs and protein (both of which are insulemic, especially when removing fat and fibre) probably won't last for the 2-4-6-10 hours+ metabolism increase (which could depend on individual clearance rates of caffeine, thus making the metabolic increase a potential connection for caffeine intolerance and decreased clearance rates by the liver.)
Basically, the idea is regular caffeine use may give you (and maintains) the improved fuel utilization and hormetic broad anti-stress benefits of regular, probably prolonged, fed and fasted exercise without having to exercise.
Exercising on a fasted, empty stomach causes up-regulation or adaptations improving ability to use stored (and probably acutely ingested) fat utilization for energy (along with increased glucose utilization ability). But this takes time. Similarly, the purported "~3 days adaptation"(from Haiduts thread) and even lasting changes can be seen as a lasting increased ability to use stored fat as energy, similarly to how exercise causes this adaptation.
Another further idea: This adaptation (resulting from increasing metabolism) gradually results in less stress hormones needed to be released as the body and cells becomes more efficient at releasing stored fat quickly, as well as all sorts of processes involved. Likewise, I'm sure increasing fitness involves improvements in the speed at which the body can mobilize resources, both glucose and fats.
Another adaptation may be an increased sensitivity to adrenalin and other hormones. I've read before about how fasting occasionally increases sensitivity to adrenaline, in a good way, similar to the concept of insulin sensitivity. Perhaps this allows the body to achieve the results it wants with less stress hormone released? i.e. by creating surges/spikes in adrenalin and cortisol, by stressful, metabolism stimulating events like exercise or caffeine ingestion, the body adapts and responds better in the future (such as with tighter feedback mechanisms, keeping stress hormones at useful rather than excessive levels, and reducing them more quickly). Smaller amounts cortisol/adrenalin will be needed to release needed amino acids for gluconeogenesis, resulting in less cortisol causing problems elsewhere.
This could all be instructive as to how preventative stress hormone spiking could actually be. Hormetic effects, from acute stressors, are anti-stress effects, and should be looked into more here.
Another consideration: The Fat Burning Zone
In light exercise, moderate to slow cardio, the body uses both fat and carbs, and as intensity increases, the ratio of carbs to fat used increases, but fat is still basically always used, and higher intensity results in higher total calories used over same time span, but one realization in the past few years that dispelled myth that fat burning zone burnt more total fat was that in both cases, moderate and high intensity, basically the same level of fat is burnt. The higher intensity also results in alot of post exercise calorie burning, which will certainly be a lot of fat burning if your only eating carbs and spiking/crashing blood sugar by not having fiber or fat with it.
The insight from the "Fat Burning Zone" is that fat is always being used for energy in all activities, on a continuum from light to vigorous, from sitting in a chair (burns more calories than laying down) to sprinting away from a raging grizzly bear, and I suspect anything that increases metabolism will instantly encourage the body to increase efficiency of both glucose and fat utilization (in more ways than cellular metabolism), and, will always do such. In this light, Caffeine, and any other metabolism booster, can be seen as a surrogates for exercise benefits, thus explaining its health protective and longevity benefits in those who use it daily, matching the humans and all animals natural "daily" highly physically active lifestyle.
Since caffeine strongly increases metabolism, like exercise does, having just carbs with your caffeine probably isn't going to prevent it from increasing fat utilization, and probably hasn't for most who have tried it here. To avoid releasing stored fat, one would do best to have fat with the caffeine. (But those using it to clear liver fat may do best to take caffeine before meals, so it reaches highest concentrations. Also on this note: It is well known in bodybuilding circles that taking metabolic boosters for fat burning "cuts" become much more effective if you take them while intermittent fasting. I suspect this could also apply to clearing liver fat)
So having just carbs and protein (both of which are insulemic, especially when removing fat and fibre) probably won't last for the 2-4-6-10 hours+ metabolism increase (which could depend on individual clearance rates of caffeine, thus making the metabolic increase a potential connection for caffeine intolerance and decreased clearance rates by the liver.)
Basically, the idea is regular caffeine use may give you (and maintains) the improved fuel utilization and hormetic broad anti-stress benefits of regular, probably prolonged, fed and fasted exercise without having to exercise.
