Metabolic Water from Glucose Oxidation

Metabolic water produced by oxidation of 1 gram of sugar (glucose) is:

Correct Answer: 0.60 g

Metabolic water is water produced inside the body during the oxidation of organic nutrients. It comprises 5–10% of the total water intake of domestic animals.

Metabolic Water Values (Per 1 gram)

• Glucose / Sugar: 0.60 g water
• Starch: 0.56 g water
• Protein: 0.40 g water
• Fat: 1.07 g water — highest of all (this is why camels can survive long periods without drinking; they oxidise hump fat)

Why Fat Produces the Most Metabolic Water?

Fat has the highest hydrogen:oxygen ratio among nutrients. The complete oxidation of 1 mol of palmitic acid (C₁₆H₃₂O₂) produces 16 mol CO₂ and 16 mol H₂O. Fat is nearly anhydrous, so oxidation yields proportionally more water than carbohydrates or protein.