To investigate whether there is a linear dose-response relationship between oral lactate and its effects on gut hormone secretion, motility, and appetite.

Hypothesis Oral lactate administration affects gut hormone secretion, insulin levels, motility, appetite sensation and the amount of food intake in a linear dose-response relationship.

The participants will meet up fasting at the Steno Diabetes Centre Aarhus Research Lab. Immediately after arrival, they will be placed in a bed. The four trial days will be completely alike, besides the interventions.

The participants will have one intravenous (iv.) access placed in the elbow on the four trial days for a continuous drawing of blood samples throughout the trial day.

Before drinking the intervention, baseline blood samples will be drawn. Immediately after drinking the intervention, the participants will take 1500 mg paracetamol to determine ventricular emptying rate through the acetaminophen test.

After this, the participants can lay in their bed and watch TV, Ipad or work on their computer. Blood samples will be collected at 0, 10, 20, 30, 45, 60, 75, 90, 105, 120, 150, 180, 210 and 240 minutes after the intervention. Appetite sensations will be measured by a visual analog scales (VAS). After 3 hours the trial day is finished, and the participants can go home.

Before and after each trial day the participants will collect a fecal sample.

We will use ANOVA and mixed model regression analyses for comparing the four groups.

Based on a previous study we will need 11 individuals to detect a difference of 17,3 pmol/L in mean insulin concentrations at time 60 minutes, with a SD of 18,3 (α=0.05, β=0.80). To account for potential missing values, we will include a total of 12 participants

Inclusion Criteria:

• 18-75 years
• Written and oral consent
• Healthy

Exclusion Criteria:

• HbA1c > 39
• Taking medicine
• Any diseases
• Allergy to paracetamol
• Doesn't speak or understand Danish.
• Special diets