The investigators want to evaluate the difference in glucose metabolism and intestinal hormonal response after a liquid meal versus a solid meal in patients after bariatric surgery.

Inclusion Criteria:

• Age > 18 years
• RYGB or SG operation > 12 months prior to inclusion
• Weight stable (± 3 kg during the last month)
• HbA1c < 48 mmol/mol before surgery, and no history of diabetes
• HbA1c < 48 mmol/mol and fasting plasma glucose < 6.1 mmol/l at inclusion

Exclusion Criteria:

• Thyrotoxicosis or inadequately treated hypothyreosis
• Hemoglobin < 6.5 mmol/l at inclusion
• Pregnancy or breast feeding
• Medication affecting the planned examinations