Do not consume tomatoes in high quantities because it increases the amount of sugar per serving (a cup of tomato sauce is like 22g+ of sugar, way too much).
Why not consume tomatoes?
I can see the reason for limiting the consumption of tomato sauce (perhaps even limiting it to zero), but I really do not see why tomatoes would be bad.
When you make or purchase sauces like marinara sauce or salsa, etc. this will increase the sugar content found in the item. So if you were to compare eating pasta with one cup of marinara (25g+ of sugar) to a single tomato that you dice and put on salad (8g of sugar or less), this is a big difference in sugar content.
Additionally, eating overly acidic foods can pose problems in that it potentially would reduce the pH of the body. Acidic pH is tied to inflammation and inflammation is tied to disease, so this is a cycle you shouldn’t get involved in if possible while on the diet.