I’ve been tracking cafeteria meals at Google for ~2 weeks and indeed, it’s not just tedious, but error-prone. to figure out quantities, you need to get a good visual grasp of what 100g (or 1oz) of whatever you eat looks like, and then also get some nutrition information. For some items, certain macro-nutrients vary wildly depending on type or brand. For example, sour cream can have either 2 or 4 grams of carbs per 2 tbsp depending on whether it’s fat-free or not.