It said, to lower calories you can try one of the following or a combination of these options:
1. Remove the bun.
2. Request no cheese.
3. Change the burger meat for chicken.
4. Remove the sauce.
5. Switch the fries out for a vegetable or salad.
Basically a low fat burger is chicken and a salad with no sauce.
Or you can just ask for an empty plate, pay for it and go home.