Aim of the study~To compare the acute effect of the consumption of a test meal on satiety, gastrointestinal hormones' response, post-meal thermogenesis, and further metabolic parameters in lean patients with type 1 diabetes mellitus (T1DM), obese patients with T1DM, and healthy lean and obese controls.~Study subjects:~Four groups of participants will be recruited, consisting of 15 lean healthy subjects (BMI <25 kg/m2), 15 obese healthy subjects, 15 lean patients with T1DM (BMI <25 kg/m2), and 15 obese patients with T1DM (BMI ≥ 30kg/m2). Groups will be matched for age and sex. Healthy volunteers will be recruited from the community, and diabetic individuals from our diabetes clinic. Eligibility criteria will include 18-65 years of age, no use of medications affecting appetite and stable weight (no fluctuations exceeding 5 kg the last 3 months.~Methods:~Demographic data and anthropometric measurements will be collected on the day of visit. Fasting blood samples will be collected for measurement of plasma glucose, insulin, triglycerides, GIP, GLP-1, PYY (total), ghrelin (total). VAS for hunger and satiety will be completed in the fasting state. Participants will then consume a test meal of ~700 kcal consisting of protein and fat (no carbohydrates) within 10 minutes. Blood samples will be drawn and VAS scales completed postprandially at 30, 60, 90, 120, 150, 180 min. RMR measurements using indirect calorimetry will be performed in the fasting state, 1 hour and 3 hours postprandially to assess meal induced thermogenesis. Postprandial responses for these parameters will be assessed as area under the curve (AUC).~Patients with T1DM treated with basal- bolus insulin therapy will receive their regular basal insulin dose and patients on an insulin pump will be kept on their basal rate of insulin infusion. In case of fasting hyperglycemia, the session will be canceled.~Postrpandial glucose excursion will be treated with fast acting insulin.
The study will compare the postprandial responses to a test meal between subjects with type 1 diabetes and healthy control subjects, in terms of gut hormone levels, meal induced thermogenesis, hunger and satiety perception, as well as futher metabolic parameters.