<P> Note that the following standardized table of energy densities is an approximation and the value in kJ / g does not convert exactly to kcal / g using a conversion factor . </P> <P> The use of such a simple system has been criticized for not taking into consideration other factors pertaining to the influence of different foods on obesity . </P> <Table> <Tr> <Th> Food component </Th> <Th_colspan="2"> Energy density </Th> </Tr> <Tr> <Th> kJ / g </Th> <Th> kcal / g </Th> </Tr> <Tr> <Td> Fat </Td> <Td> 37 </Td> <Td> 9 </Td> </Tr> <Tr> <Td> Ethanol (drinking alcohol) </Td> <Td> 29 </Td> <Td> 7 </Td> </Tr> <Tr> <Td> Proteins </Td> <Td> 17 </Td> <Td> </Td> </Tr> <Tr> <Td> Carbohydrates </Td> <Td> 17 </Td> <Td> </Td> </Tr> <Tr> <Td> Organic acids </Td> <Td> 13 </Td> <Td> </Td> </Tr> <Tr> <Td> Polyols (sugar alcohols, sweeteners) </Td> <Td> 10 </Td> <Td> 2.4 </Td> </Tr> <Tr> <Td> Fiber </Td> <Td> 8 </Td> <Td> </Td> </Tr> </Table> <Tr> <Th> Food component </Th> <Th_colspan="2"> Energy density </Th> </Tr>

How much energy in 1 gram of fat