Increasing the protein:carbohydrate ratio in high fat diets attenuate obesity development and increase UCP1 expression in mice kept at both 22°C (Madsen et al., 2008) and at thermoneutrality (Ma et al., 2011), but obesity development and feed-efficiency in mice kept at the two different temperatures have not yet been directly compared. The gene discussed is UCP1; the disease is obesity due to melanocortin 4 receptor deficiency.