Fig. 2.

Stable-isotope study design. Recruited subjects arrived at the Metabolic Research Center after a 10–12 h fast. An intravenous line was placed and a baseline blood draw was taken. Subsequently, subjects were given meals, a sugar-sweetened beverage, and the oral stable-isotope 1-¹³C acetate, and blood was drawn as outlined above. We used oral isotopes in a previous study and found that this type of administration was very effective (8).