What is the scientific reasoning of the theory of splitting meals into P+F and P+C like Berardi suggested?
Fat consumption slows down gastric emptying which MAY lower the insulin response to a meal.
Also, your stomach is never empty during the day; in other words, it won't be empty before you eat your next meal.
Bryan Haycock stated that avoiding combining C + F does have merit -- but only when hypercaloric. If hypocaloric, it would not matter.
On the other hand, it serves a good purpose by detering people from consuming junk food with high refine carbs + fat and it macronutrient splitting is useful before and after workouts.