There is popular belief that potatoes are fattening and eating other vegetables like tomato are much better for our health.
Let us look at the nutritional profile of both both potato and tomato:
Nutritional value of potato with skin
Nutrition Facts: Serving Size 100 g
Calories 77
Total Fat 0.1g
Sodium 6mg
Total Carbohydrate 17g
Dietary Fiber 2.1g
Sugar 0.8g
Protein 2.1g
Vitamin A 0% of daily requirement
Vitamin C 33% of daily requirement
Calcium 1% of daily requirement
Iron 4% of daily requirement
Source: https://www.nutritionvalue.org/Potatoes%2C_raw%2C_flesh_and_skin_nutritional_value.html
Tomato Nutrition Facts
Serving Size 100 g
Amount Per Serving
Calories 16
Total Fat 0.2g
Sodium 42mg
Total Carbohydrate 3.2g
Dietary Fiber 0.9g
Protein 1.2g
Vitamin A 30% of daily requirement
Vitamin C 27% of daily requirement
Iron 3% of daily requirement
Source: https://www.nutritionvalue.org/Tomatoes%2C_raw%2C_orange_nutritional_value.html
Our body requires carbohydrates, fat, protein, minerals and other immunity building molecules like antioxidants etc. The nutritional requirements vary from individual to individual. Customizing the diet to your need is important. The question is not prefering one over the other but about consuming a balanced diet.
If you would like to know more about the facts on nutrition, you can check here.