Washington, June 8 -- Mice genetically engineered to lack the ability to make the amino acid cysteine, and fed a cysteine-free diet, lost 30 per cent of their body weight in just one week, a new study shows.

Published online May 21 in Nature, the work found that cysteine depletion disrupts the normal metabolic pathways mammalian cells use to convert food into energy, forcing the animals to rapidly burn fat stores in a futile attempt to meet energy demands.

Led by researchers at NYU Grossman School of Medicine, the study reveals key details about how cells process fuels like carbohydrates and fats (metabolism), and how cysteine depletion affects tissues.

Experiments showed that lowering cysteine levels caused a drop in levels of the sma...