Most rodent CR experiments use very severe CR that humans can't tolerate. Lifespan studies suggest that the extension of healthy life is proportional to the degree of CR, starting from a mouse colony's characteristic nonobese baseline. A series of studies in posted in this week's Weekly research updates by CR Society Board member James Cain drills down into the anthropometric and metabolic effects of graded doses of CR, and the parallels (or not!) of equivalent levels of protein restriction. Plus the effects of CR iin lean and obese strains of laboratory ra, and the effects of methionine restriction on adipose tissue mitochondria.