Even though obese people have higher blood sugar after eating carbs, their bodies still break down and use the sugar from those carbs just as well as lean people do.

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.

Scientists tested whether giving insulin to men who are obese and have mild diabetes changes how their fat tissue processes sugar. They found that at normal insulin levels, it doesn't really matter - the fat tissue's sugar burning stays the same.

Insulin reduces fat burning in the blood the same way in obese and lean people, but obese people still burn more fat overall because their bodies are burning fat stored inside cells — not just from the blood.

After eating just three days of mostly fatty food instead of carbs, healthy young men had higher blood sugar spikes when they drank a sugary drink, meaning their bodies handled sugar less efficiently.

If you swap out a small amount of fatty foods for sugary or starchy ones for six weeks, your body releases less insulin after eating—even though your blood sugar goes up the same—which might mean your pancreas isn’t working as well.