I had some time over the Christmas holiday and needed to get blood tests done. I decided to do an N=1 of the following:
- What happens to blood lipids for water-only fasting versus drinking (black) coffee/tea?
- What happens to insulin when drinking coffee/tea?
The upper row is water-only fasting, 12+ hours fasting (I think around 13 hours). Blood draw at 8:10am. I then chugged, as quickly as I could (which is not that quick, given the short time period between blood draws) the following:
- 16 ounces of coffee (3/4 cup cold-brewed coffee, diluted to about 16 ounces)
- 2 cups Pu-Erh tea
Both black (no cream, nothing added at all).
The lower row is the second blood draw, at 10:36 am. Here are the results:
There is basically no change in lipids.
For insulin, I’m unsure of how to interpret this. I was hoping for something larger. Also, I usually drink my coffee at about 6am, then one cup of Pu-Erh tea at about 9am. Usually only one cup (5+ days/week). Sometimes, two cups, maybe 1/week. Every once in a great while (once a month?), three cups.
Additionally, what is the increase of 3 uIU/ml relative to, say, eating a lower fat, high protein lunch?
I don’t think I’ll change my coffee/tea drinking based on this. And I guess I needn’t be concerned about drinking coffee/tea for lipids.
Caveats: I did not get blood sugar taken on the first test. That was probably a mistake; it might have added some data. I had some carbs over the Christmas holiday, so my trigs are about 30 points higher than “normal”. My AST, ALT, and ferritin were much higher than normal (carbs?), but I don’t get these tested enough to know why (could some carbs beforehand change them?). My Lp(a) was shockingly low (1/3 less than normal).
