The tomato is a vegetable wich has given controversy for his classification between fruit or vegetable. From a botanical point of view the tomato is a fruit because it contain seeds. However, despite other reasons as not being used for desserts and being served in lunch is populary classified as vegetable.
The tomato contains not much calories because the 95 % of his weight is water. It has an bittersweet despite a smaal acount of simple sugars and some organic acids (as the citric and malico) which make us see it as appetizing and digestive.
If we compare it with other fruits and vegetables it has not much fiber, but the seeds, the pulp and the skin are enough to improve the digestive transit.