Kirsteen, it looks like your parents are already eating a low carb diet, albeit higher carb than Atkins for example. Consider what is not in their diet: Soft drinks, grain-based meals, processed foods of all kinds, etc. Also consider what their parents fed them when they were kids. It must have been different from their own adult diet. Your childhood diet was closer to their adult diet than their childhood diet. As their adult diet changed, so did your adult diet change. We're not really talking about different body chemistry here. We're really talking about the evolution of diet over 75-100 years.