The phrase "portion sizes" refers to the amount of food or drink that is served or consumed in one sitting. It is about how big or small each serving is. Full definition
The purpose of including GL values in the revised table was to allow comparisons of the likely glycemic effect of realistic portion sizes of different foods. (academic.oup.com)
I am making sure all sweet recipes on the blog are small portion sizes for children. (anniesdorsetkitchen.com)
I struggled a bit to decide on portion size for this recipe. (simplysohealthy.com)