You have it wrong... there's no recommended daily dose of Refined sugar for sure.
You definitely need to eat products that contain sugars, or you will die.
I know that not eating fats and proteins will kill you, but not eating sugars (or at least extremely low quantities) will not kill you (I might be wrong, I'm not a doctor). For example Ketogenic diets have been studied for almost a 100 years by modern medicine, and is used very effectively to control epilepsy. A general public version is known as the Atkins Diet.
The ketogenic diet is a high-fat content diet in which carbohydrates are nearly eliminated so that the body has minimal dietary sources of glucose. Fatty acids are thus an obligatory source of cellular energy production by peripheral tissues and also the brain.
In the absence of glucose, the preferred source of energy (particularly of the brain), the ketone bodies are used as fuel in extrahepatic tissues.
there is evidence from uncontrolled clinical trials and studies in animal models that the ketogenic diet can provide symptomatic and disease-modifying activity in a broad range of neurodegenerative disorders including Alzheimer’s disease and Parkinson’s disease, and may also be protective in traumatic brain injury and stroke
I don't have any specific citations but some believe that Alzheimers is like a form of brains diabetes, where the brain cells are no longer able to absorb sugars, which might be caused by modern high sugar diets. Switching to a Ketogenic diet, bypass the brain inability to feed on sugars and is fed ketone bodies instead, potentially reversing the symptoms.