No tomatoes are not very high in calories.
One full size tomato contains around 35 calories so that's not all that much when it comes to calories.
If you eat too many tomatoes though then your calories intake would be higher but even then it would take at least 10 to 20 tomatoes to even cause you to consume enough calories to cause weight gain.
Tomatoes are a healthy food and are a good choice of food to eat when you are trying to lose weight.
Tomatoes are also very healthy for you and tomatoes are very rich in vitamins such as vitamins A and C, many B vitamins and some minerals.
Cherry tomatoes are even lower in calories and 5 cherry tomatoes contain around 20 calories.