RQ is the respiratory quotient. His equation represents carbon, oxygen, and hydrogen metabolism. But, for specific macronutrients, it breaks down like this.
c6h12o6 + 6 O2 -> 6 CO2 + 6 H2O the gas exchanged is equal so... rq = 6 co2 / 6 o2 = 1.0
If we take his 16 co2 it would leave fat with an RQ of 0.696 round up to 0.7
c16h32o2 + 23 o2-> 16 co2 + 16 h20 16 co2 / 23 o2 = 0.696
Fat also oxidizes much slower due to this fact.