Reasons fructose causes metabolic problems that glucose doesn’t.
What the evidence says
- Insulin sensitivity decreased 17% in fructose group (no change in glucose group) over 10 weeks[1]
- Women showed greater insulin sensitivity decline (23.6%) than men (11.7%) on fructose[1]
- Visceral fat increased only in fructose group (not glucose) at equal calories[1]
- Multiple lipid markers worsened only with fructose: apoB, LDL, small dense LDL, oxidized LDL[1]
- Fasting triglycerides did not increase with fructose, but 23-hour postprandial triglyceride AUC markedly increased (P < 0.01) — standard fasting lipid panels miss fructose's lipid effects[1]
- In mice, fructose uniquely increased SREBP1c and downstream fatty acid synthesis genes, a proposed mechanism from animal work[2]