According to Ellen Yack, B.Sc., M.Ed., O.T., Shirley Sutton, B.Sc., O.T. & Paula Aquilla, B.Sc., O.T. in the article “Ask the Expert: The Wilbarger Protocol for Sensory Defensiveness“:
A sensory diet is a planned and scheduled activity program designed to meet a child’s specific sensory needs. Wilbarger and Wilbarger (1991) developed the approach to provide the “just right” combination of sensory input to achieve and maintain optimal levels of arousal and performance in the nervous system. The ability to appropriately orient and respond to sensations can be enhanced by a proper sensory diet. A sensory diet also helps reduce protective or sensory defensive responses that can negatively affect social contact and interaction.
There are certain types of sensory activities that are similar to eating a “main course” and are very powerful and satisfying. These activities provide movement, deep-touch pressure, and heavy work. They are the powerhouses of any sensory diet, as they have the most significant and long-lasting impact on the nervous system (Wilbarger, 1995; Hanschu, 1997.)
There are other types of activities that may be beneficial, but their impact is not as great. These “sensory snacks,” or “mood makers,” are activities that last a shorter period of time and generally include mouth, auditory, visual, or smell experiences.
A sensory diet is not simply indiscriminately adding more sensory stimulation into the child’s day. Additional stimulation can sometimes intensify negative responses. The most successful sensory diets include activities where the child is an active participant. Every child has unique sensory needs, and his sensory diet must be customized for individual needs and responses.