Physical Inactivity and Appetite Regulation

To contextualize the changes in ad libitum food intake driven by two weeks of physical inactivity, a sub-study will assess the effect of GLP-1 infusion on ad libitum food intake compared with a saline control in 20 participants included based on same eligibility criteria as in the main study. The estimated GLP-1 induced change in ad libitum food intake will be descriptively compared to the estimated GLP-1 + inactivity induced change in ad libitum food intake (main-study) to provide context for any attenuation in appetite suppression observed in the main-study. Outcomes related to subjective appetite measures (hunger, satiety, and food preference) will also be assessed in this way.

The primary hypothesis is that GLP-1 infusion will suppress appetite and reduce ad libitum food intake compared with saline control. The secondary hypothesis is that GLP-1 infusion will diminish subjective feelings of hunger and increase satiety.

Inclusion criteria

• Male
• Age ≥ 40 years and ≤ 55 years
• Body mass index (BMI) > 20 and < 25 kg/m2
• Physical activity level should as a minimum include: Active commuting by biking a minimum of 10 km, four days per week or an equivalent amount of other physical activity four days per week.
• Healthy (based on self-reporting, pre-study medical examination and biochemical screening)
• Can adhere to two weeks of inactivity (refrain from running, cycling and all other exercise while reducing steps to max. 1500 pr. day)
• Caucasian
• No change in body weight > 5 kg within the last 6 months
• Eats breakfast and lunch daily
• Does not follow specific dietary restrictions
• No disliking of spaghetti bolognese
• No diagnosis of psychiatric disorder or treatment with anti-depressant or anti-psychotic medication
• No history of suicidal behavior or ideations.
• No previous surgical treatment for obesity
• No cardiovascular disease
• No rheumatologic disease
• No metabolic/endocrine disease
• No liver disease (ASAT or ALAT >2x upper normal range)
• No other chronic disease
• No elite sports
• No frequent or chronic use of medications affecting bodyweight, physical performance, or inflammation (NSAIDS, DMARDS, corticosteroids)
• No current infection
• No history of cancer
• No anemia (hematocrit <33%)
• No smoking
• No participation in other research intervention studies

Exclusion criteria

• Clinical or biochemical signs of disease
• HbA1c > 39 mmol/mol
• Unable to allocate the needed time to fulfill the intervention
• Language barrier, mental incapacity, unwillingness, or inability to understand and be able to complete the interventions