Daniel Marks and his colleague Kevin Grove of Oregon Health and Science University studied the effects of a high-fat diet on developing organs using a non-human primate animal model. These photographs show the livers of fetuses from monkeys whose mothers had been fed either a regular low-fat diet (control) or a high-fat, high-calorie diet. The livers were treated with a compound (oil-red O) which stains fat deposits red. Significantly more fat deposits can be seen inside fetal liver cells in the high-fat diet group, a picture reminiscent of fatty liver disease commonly experienced in alcoholics.