What the authors were interested in were the differences, in the same individuals, of having a high protein breakfast vs. skipping breakfast (first meal at noon), on hunger, fullness, desire to eat, prospective food consumption (PFC) and related hormones, food cue–stimulated functional magnetic resonance imaging (fMRI) brain scans, ad libitum evening food intake, sleep quantity and sleep quality.
The participants were healthy young men and women without obesity and each arm of the experiment lasted for 7 days with a 3 day washout period in between.
The results saw breakfast eaters see their hunger, desire to eat, PFC, and ghrelin levels decrease on breakfast days versus skipping days, while their fullness and related hormones increased.
What didn't differ however was total energy consumed, this despite the fact that when they ate breakfast, participants on average consumed 30% fewer carb based evening snacks. There was also no real impact on sleep or sleep markers.
What was great about this study was that it didn't just look at next meal consumption, but rather the impact of breakfast on whole days, something my clinical experience has been screaming for years was necessary. That said, at least in this short study, it didn't seem to matter, at least not to total daily energy intake.
So does this mean you shouldn't skip breakfast? Not exactly, but it does suggest that eating a high protein breakfast, though it won't make you eat fewer calories, it may leave you feeling fuller and decrease evening processed food snacking.
And so once again, the answer is personal and not particularly complicated. If breakfast helps you to eat less, eat better, or feel better, then yes, you should eat it, and if it doesn't, don't.