Studies have shown that by eating a high protein breakfast, you are more likely to feel fuller throughout the day and therefore eat fewer snacks and a smaller dinner. Doing so has also been shown to help you wake up, feel more alert and feel energized, without the dependence on caffeine. These recommendations also come with the reminder to not eat more protein than what your body can comfortably digest at one time. Overeating anything, protein included, can tax your digestion and have adverse effects.
SOURCE: Leidy HJ, Ortinau LC, Douglass SM, Hoertel HA. Department of Nutrition and Exercise Physiology, School of Medicine, University of Missouri, Columbia, MO. The American Journal of Clinical Nutrition. 2013 April;97(4):677-88. As sited here: http://greatist.com/health/high-protein-breakfast-benefits