<Tr> <Th> Name of the substance </Th> <Th> Respiratory Quotient </Th> </Tr> <Tr> <Td> Carbohydrates </Td> <Td> </Td> </Tr> <Tr> <Td> Proteins </Td> <Td> 0.8 - 0.9 </Td> </Tr> <Tr> <Td> Ketones (eucaloric) </Td> <Td> 0.73 </Td> </Tr>

When are amino acids used significantly as an energy fuel