Going grain/sugar free doesn't lead to weight loss for me unless I actively restrict intake at the same time. For me, it's all about the calories and going grain free/sugar free won't automatically lead to a deficit.
I think it's because I don't have a sweet tooth, I've got a umami tooth. So, give me a well-seasoned piece of chicken or steak, or cheese, and I can easily over consume. Easily.
You know how some people can't stop at a serving of ice cream or candy? Well, that's me with protein. I have to be very careful or I am at the refrigerator jamming in multiple pieces of grilled chicken breast, followed by multiple pieces of string cheese, feeling so hungry and unable to satiate it.
Sometimes I feel like the only person in the world who gains weight on low-carb diets. For me, I do best with a healthy moderate diet in which all food groups are represented.