I watched a video a while back by Dr MacDougall (he of the 'plant based diet' mantra), and one of the things he mentioned as an arguement in favour of eating carbohydrates instead of fat was that your blood run swiftly when you are eating carbs, and is sluggish and lethargic when eating a fat based cue. I tried digging further but only found rodent studies.

Cue my personal experience.

I was donating plasma this morning (like a blood donation, they draw off your blood, but then they centrifuge it and siphon off the blood plasma and then pump the red blood cells back into me). The machine errored on 3 of the 4 cycles because it timed out returning my blood cells to me. Basically, my blood was too viscous for the machine to return it all to me within the timeframe allotted by the machine settings. The nurses had never seen this before.

Do people have any explanations for this? From what I can tell, increased blood viscosity is a known side effect of a high fat diet, but the exact mechanism is unclear (one site I read posited that it was due to excess serum triglycerides cloating the surface of the red blood cells, which slowed them down and made them stick to each other, although this was speculation only).

Anyway, just thought that I would throw it out there. I'm wondering if I should intentionally eat more tubers (carbs).