Just curious what the advantage of low carb/mediumn fat/high protein over low fat/medium carb/high protein is?

The obvious reason seems to be that the insulin levels are constantly VERY low when on a almost zero carb(except pwo, ppwo)diet and the body then utilizes fat more efficently as a energy source.

But would the same result be possible if doing very low fat(just the vital ones), medium carb and high protein if you do EVERYTHING humanly possible to lower gi to very low levels. Im talking about washing down ****loads of psyllium seeds before every meal, Im talking using alot of r-ala, metformin, cinnamon and every other substance know to man that increases insulin sensitivity and I mean the only carb sources(again except pwo,ppwo)is brown rice, poatoes(first boiled then reheated so the gi is mega low) and other very low gi complex carbs.

Would it be possible then to keep the gi of each meal so low and the slin sensitivity so high that slin levels will be stable and the extra carbs will be good during workouts and cardio(didnt someone once say that fat burns in the carb flame or something along those lines )

Im just curious to why low carb is the norm nowdays while it wasnt 10 years ago but the guys(competetive bb'ers) back then where usualy as conditioned as todays