It's okay to eat a little bit of Quinoa when on a low Carb diet however it's best to avoid eating Quinoa on a low carb diet since Quinoa which is not a vegetable contains more carbohydrates than vegetables do.
So Quinoa is not really a good choice of food to eat when being on a low carb diet to lose weight.
It's best to eat vegetables instead that are low in carbohydrates when on a low carb diet for the diet to be successful.