Kiwi is spot on..any excess calories consumed will be stored as fat ,from carbs,fats or protein,your body uses what it needs and stores the rest as lard.Add in training and even drugs and this turnover changes but you still will only use what you need , any excess will be stored as fat..complex carbs with make you fat if you take in more than you need.
Again he is correct when saying everyone is different , we cant be pigeon holed all into one box..what works for you may not work for me,differing metabolisms,hormone eficency etc the list goes on and on.
Its all trial and error to see what works for you as an individual but to say Complex carbs dont make you fat is rubbish.
That's the thing with people nowadays - they needlessly complicate things. Are you fat? Then just eat less and exercise more. Are you skinny and not putting on weight? Then just increase your caloric intake via whole foods and focus on compound movements in the gym where your goal should be to try and get stronger over time, which is the easiest way to progress.
But that would mean that the experts out there aren't needed and so, up they come with this bullshit about numbers and number of carbs and grams per pound of bodyweight and all that - stuff which only the elite and people who are competing need to use, to keep close track of how they are changing over time so they can keep working on it and peak properly for whatever it is that they are preparing.
The average person who wants to gain a few pounds of muscle or lose a few pounds of fat has absolutely no need to get to exact with numbers, at least for the first 90% of the gaining or cutting phase. They should just bump up their protein, make sure everything is balanced diet wise and focus on getting stronger in the gym, where they should use compound movements. Similarly, if they are trying to lose fat, they should just cut down their food intake as well as the amount of junk food that they eat and be more active physically. It's that simple.
Instead, you've got people spending hours and hours debating irrelevant things. No one wants to put in the effort - they just try and make up for it with some fancy theory or study, which is never going to help. And some time later, they can't settle down on any theory due to all the inconsistencies and counter arguments and give up, thinking that the 30,000 diets out there are BS and that none of them work. The current generation is just shocking this way.