Complex sentence: The PDCAAS method may also still be considered incomplete, since human diets, except in times of famine, almost never contain only one kind of protein--however, calculating the PDCAAS of a diet solely based on the PDCAAS of the individual constituents is impossible.
Split into simpler sentences: The PDCAAS method may also still be considered incomplete, since human diets, except in times of famine, almost never contain only one kind of protein. However, calculating the PDCAAS of a diet solely based on the PDCAAS of the individual constituents is impossible.