Fructose has a low glycaemic index because it skips the blood entirely and goes straight to the liver, and the health aisle sold that as a virtue. The glycaemic index measures one thing: how much a food raises blood glucose. Bread scores seventy. Table sugar scores about sixty. Fructose scores around twenty, and agave syrup, which is up to ninety per cent fructose, is marketed to diabetics on that number. The number is low because the glucose meter never sees the fructose. It is pulled out of the portal blood by the liver on the first pass and dealt with there, and the meter reads clear while the liver does the work. Inside the liver the enzyme that grabs fructose has no off switch. It runs regardless of how full the cell is, the excess is turned into fat on the spot, and the reaction spits out uric acid on the way, which raises blood pressure and fills the joint of a gout sufferer. And because fructose does not raise blood glucose it does not raise insulin, and because it does not raise insulin it does not raise leptin, the hormone that tells your brain you have eaten. The low GI sweetener is the one that leaves you hungry. So the number that made it diabetic-friendly is the number that proves it never checked in.Fructose has a low glycaemic index because it skips the blood entirely and goes straight to the liver, and the health aisle sold that as a virtue.
— Sama Hoole (@SamaHoole) September 8, 2026
The glycaemic index measures one thing: how much a food raises blood glucose. Bread scores seventy. Table sugar scores about sixty.… pic.twitter.com/Qbttc8VLwg
A sugar that dodges the test is not a safe sugar. It is a sugar that has found the back door.
