Experimental Overfeeding in Humans

Metabolic Changes in Response to Experimental Overfeeding: A Randomized Intervention Study

The objective of this study is to determine the homeostatic mechanisms that counteract weight gain in response to experimental overfeeding.

The homeostatic regulation of body weight implies that biological processes have evolved to protect energy stores from changes to the food environment. Accordingly, many individuals remain remarkably weight stable over years without carefully considering how much they eat or how much energy they expend, which has given rise to the theory that body weight is regulated around an individual biological 'set point'. Notably, overfeeding humans in experimentally controlled conditions, support this phenomenon, but the underlying mechanisms are unknown.

To systematically map out the components of the overfed state, the investigators will execute a 2-week randomized controlled overfeeding trial in lean and overweight individuals. The trial is preceded by a 1-week lead-in period and followed by a 2-wk controlled ad libitum study period. The comparison between lean and overweight subjects, men and women, enables the determination of whether a differential response in overfeeding-induced signals is present in relation to BMI and sex.

Inclusion Criteria:

• Male or female otherwise healthy subjects
• 20-40 years of age
• BMI (Body mass index) between 22-30 kg/m2

Exclusion Criteria:

• Present or previous cardiovascular disease, diabetes or thyroid-disease
• smoking
• more than 3 hours of planned physical activity per week