Ghrelin does not orchestrate the metabolic changes seen in fasting but has significant effects on lipid mobilisation and substrate utilisation.

Objective: Short-term fasting is associated with increased GH pulsatility and mobilisation of fats, but underlying mechanisms are unclear. We studied ghrelin's role during fasting and the effects of exogenous ghrelin on lipid mobilisation.

Design: Randomised placebo-controlled study.

Ghrelin restores 'lean-type' hunger and energy expenditure profiles in morbidly obese subjects but has no effect on postgastrectomy subjects.

Objective: To examine the effects of ghrelin on appetite and energy expenditure in lean, obese and postgastrectomy subjects.

Design: A randomized, double-blind, placebo-controlled study.

Patients: Nine lean subjects (mean body mass index (BMI) 23.