Non-Nutritive Sweetener Consumption and Glucose Homeostasis in Older Adults With Prediabetes

This study examines how regular consumption of artificial sweeteners (like those in diet sodas) affects blood sugar regulation in older adults who already have prediabetes. Participants will follow a controlled diet for 8 weeks to test this effect. You may be eligible if: - You are 40 years old or older - You have been diagnosed with prediabetes (fasting glucose 100–125 mg/dL, 2-hour glucose 140–199 mg/dL, or HbA1c 5.7%–6.4%) - Your weight has been stable for the past 6 months - Your BMI is less than 40 - You currently consume less than one serving of artificial sweeteners per week - You are able to pick up study food daily for 8 weeks You may NOT be eligible if: - You have full diabetes or take diabetes medication - You have used antibiotics, probiotics, or prebiotics in the past 3 months - You have high blood pressure above 159/99 mmHg (uncontrolled) - You have inflammatory bowel disease, heart disease, stroke, or cancer - You are vegetarian or vegan - You are pregnant, breastfeeding, or planning to become pregnant - You have food allergies, phenylketonuria (PKU), or use estrogen or testosterone Talk to your doctor to see if this trial is right for you.