Graded Insulin Suppression Test P&F

This study is testing a procedure called the Graded Insulin Suppression Test (GIST) to measure how well insulin controls blood sugar (insulin resistance) in people who are either lean or overweight. It is a research test comparing people who have normal vs. high insulin levels while fasting. **You may be eligible if...** - Your BMI is either 18–25 (healthy weight) or 30–45 (obese range) - You are able to understand written and spoken English or Spanish - Your fasting insulin level is either 4–10 µU/mL (normal group) or 13 µU/mL or higher (high insulin group) **You may NOT be eligible if...** - You have pre-diabetes or diabetes (HbA1c of 5.7% or above, or elevated fasting glucose) - Your blood pressure is very high or very low outside normal ranges - You have abnormal heart rhythms or ECG findings - You are unwilling to use a bedpan or avoid phone use during the test - You have lost more than 5% of your body weight in the past 6 months Talk to your doctor to see if this trial is right for you.