The best way to avoid eating ketchup with added sugar is to replace all usages of ketchup with mayonnaise.
[1] https://www.primalkitchen.com/products/organic-unsweetened-s...
A tablespoon of the most HFCS sweetened ketchup is 20 calories.
It may be a win on taste but I'm not sure it's a win on calorie reduction. I do love some mayonnaise fries, tho.