Mid-morning fatigue may result from an insufficient breakfast of animal protein.
It’s desirable that at least one third of the daily protein intake be derived from animal sources such as eggs. Some high quality protein, as from eggs and other animal products, should be included in every diet. The tissues must have all of the essential amino acids for cell synthesis. Eggs provide these!
(IronMan Magazine July 1976 Vol. 35 No. 5)