Figure 1

Metabolic steps accounting for a lower efficiency of fructose compared to glucose. Fructose conversion into glucose in the liver, followed by glucose oxidation in extrahepatic cells requires the use an additional 2 ATPs compared to the direct oxidation of blood glucose; this is associated with a higher ATP used/ATP synthesized ratio, and thus to a higher energy cost of net ATP gained. F-1-P: fructose-1-phosphate; G-6-P: glucose-6-phosphate; DHAP: dihydroxyacetone-phosphate; GAP: glyceraldehyde-phosphate; GAH: glyceraldehyde; LAC: lactic acid.