The last of the tridoshas, Vata, is peculiar because it is made out of elements completely different from the other two doshas.
Vata is associated with movement; be it your blinking, heartbeat or the flow of oxygen and carbon dioxide in and out of your lungs.
People with Vata dominance are more likely thin. They are also generally enthusiastic and creative. When not in balance, Vata people tend to be flighty and erratic and this could clinically present as constipation, anxiety and/or insomnia.
An appropriate diet includes dense, nourishing food like oatmeal or lentils. These individuals also benefit from wearing layers such as blankets or sweaters to stay warm and cozy!
Source: Lad, Vasant. The Textbook of Ayurveda, Volume One. The Ayurvedic Press: Albuquerque, 2002.