When healthy people eat a carb-rich meal, their muscles get more blood flow and their blood vessels relax, even though their body also sends signals to tighten blood vessels—this might help their body absorb sugar from the meal better.

When insulin goes up after eating carbs, it lines up with bigger blood flow to muscles, looser blood vessels, and more nerve signals telling vessels to tighten—suggesting insulin might be linked to all these changes happening together.

Eating carbs makes your body naturally release insulin for a short time—this is different from when doctors give insulin through an IV for a long time.

After eating carbs, the body turns up the 'stress signal' to blood vessels, but the vessels still open up instead of tightening—meaning the body’s normal 'squeeze' signal isn’t strong enough to block the opening.

People with obesity tend to have higher insulin levels when fasting and their blood sugar spikes more after eating carbs, but their bodies still use the sugar from those carbs just like lean people do.

If you're overweight around the middle and eat a meal full of carbs, your blood sugar and insulin spike more than if you ate a meal with lots of butter or olive oil—but your body doesn’t make as much insulin for how much sugar is in your blood.