That’s true of the metabolic pathways for fat, protein, and alcohol, too. Each oxygen molecule we breathe feeds into chemical reactions so that it picks up a carbon atom and becomes CO2 on the way out. The carbon comes from whatever food was metabolized, including anaerobic respiration where the lactic acid eventually gets cleared out.
Sugar plus oxygen equals energy plus CO2 plus water.
That’s true of the metabolic pathways for fat, protein, and alcohol, too. Each oxygen molecule we breathe feeds into chemical reactions so that it picks up a carbon atom and becomes CO2 on the way out. The carbon comes from whatever food was metabolized, including anaerobic respiration where the lactic acid eventually gets cleared out.