Do you mean sugar or carbohydrates. You are actually advocating that human beings can live on zero carbohydrates?
Absolutely. I try to eat no carbs at all.
Mr. McGowan is quite right. There are 8 amino acids that are essential and that we get from proteins; there are 2 essential fatty acids that we get from, yes, FAT; however, there are NO essential carbohydrates. None. We can make any carb we need from stuff lying around our metabolic milieu.
What I DO tell my patients who low carb it is that the only side effect is constipation, so a fiber supplement is recommended.