I've searched the forum but haven't come across the answer to this question. If this is a topic discussed before and I missed it, then if someone would just point me to that thread I'll go away.

Anyway, does anyone know how 60g carbs per day was chosen as the limit on a low carb diet? It just seems to me that this would be an approximation that would vary greatly depending on a person's gender, metabolism, height, weight, body-fat, and exercise level. I would think some people are unnecessarily restricting the carbs each day and could have more while others would have to only take in 40g or 50g carbs per day.

Can anyone enlighten me as to the science behind the 60g per day limit?