Question: what are the three stages of metabolism?
Answer: Stage one. Nutrients are digested into absorbable units, into the blood and moved to tissue cells.
Stage two anabolism. nutrients are made into macromolecules.
Stage two catabolism. Catabolism: nutrients broken down into pyruvic acid and acetol CoA. ... 
Stage three. CO2 released. ... 
Proteins. ... 
Carbohydrates. ... 
Fats.