Dietary carb is not necessary for the HFD-induced insulin resistance but a small amount of it can induce a maximal level of insulin resistance in mice on HFD.

<p>(<b>A</b>) Fasting blood glucose was measured once a week after an 8-hour fast. (<b>B</b>) Plasma level of insulin was evaluated at the end of the 5-week experiment after an 8 hour fast. (<b>C–D</b>) Insulin tolerance test (ITT) was performed at the end of the 5-week experiment after an 8 hour fast and the area under curve was calculated. Results represent mean ± SD of 8 mice/group. *: P<0.05 vs. CD. **: P<0.01 vs. CD. #: P<0.05 vs. HFD +0.1% carbs. ##: P<0.01 vs. HFD +0.1% carbs. $$: P<0.01 vs. HFD +5% carbs. ++: P<0.01 vs. HFD +10% carbs.