Inclusion Criteria:  Healthy. Age 18-40 y. BMI between 18.5 kg/m2 and 30 kg/m2 (both inclusive). Willing to fast and not to consume non-caloric stimulant for 12h before the assessments. Willing to avoid moderate or vigorous physical activity during 24-48h respectively. Have a stable body weight over the last 3 months (changes ≤3 kg) and not being enrolled in a weight loss program.  Exclusion Criteria:  Smoking or use of tobacco products within the last 3 months. Diagnosed with diabetes. Previous bariatric surgery (or other surgeries) for obesity or weight loss. Use of medications affecting metabolism or sleep. History of neurological disease. History of cardiovascular disease, including hypertension, or other chronic diseases. Pregnant, planning to become pregnant, or breastfeeding. Adherence to special restrained diets (e.g., low-carbohydrates, low-fat, or vegetarian/vegan diets) over the last 3 months. Claustrophobia impeding to stay calm under a plastic canopy.