Ya I wish I had some scientific proof to back it up. But I feel like it is common sense especially if your trying to gain weight. If you lift in the morning fasted your body's only source for real energy is what you ate yesterday. And unless you were carb loading all the protein that you ate is already metabolized. And I know that nobody into fitness likes to eat carbs at night. So lifting fasted is only going to put your body into a catabolic state. Because when you wake up your body is in the early stages of starvation craving nourishment and the first thing your body uses for energy while in this state is muscle not fat. It's kinda like overtraining just counterproductive.
i agree with lift and eat. It is science your body is catabolic in the morning, in a starving state. If you're trying to grow you shouldn't train fasted..
Usually i'll wake up, eat 4 whole eggs, 3-4oz gd beef or sirloin, and then some carbs (sometimes 2xtoast + jelly w/ banana, othertimes hashbrowns, bagles with nattypb, english muffins, etc)
wait b/w 40min - 1hr then go to gym (4 minute drive) do about 30 minutes of prehab (depending on muscle group maybe less)
then train.