From the research I've done, the general consensus is that it is really difficult to lose fat and gain muscle at the same time unless you are new (in which case at least some of those gains are coming from improved CNS efficiency) or devote a lot of time to micromanaging diet. I don't have the time for that.
If your goal is to build muscle and lose fat you need to do a bulking/cutting cycle where you do one or the other, not both at the same time.
I know from personal experience that I didn't make any appreciable strength gains until deciding to eat at a caloric surplus and lifting heavy, including drinking half a gallon of milk daily for the calories and protein.
When I started doing that my numbers shot up very quickly. Yes, I gained some fat, probably more than I should have because I wasn't as strict at watching my calories as I could have been. Don't care. I've successfully cut before and know that when it comes time for a cutting cycle I will easily be able to lose 1 to 2 pounds a week and keep most of my strength gains.
Discipline takes time to build up. Most people have a hard enough time making it to the gym three days a week, let alone changing their whole eating routine. Much easier for new people to just add a gallon or half gallon of milk daily to their diet and supplement with protein powder.
Also I don't buy that breakfast is some vast conspiracy by cereal corporations.
And several peer reviewed studies have shown a link between increased performance and mental alertness from eating breakfast, especially a high protein breakfast.