lvysaur
Member
- Joined
- Mar 15, 2014
- Messages
- 2,287
All the regions with widespread lactase persistence are carb-deficient environments. Either they are hot/arid (no water for crops), or dark (no light for crops).
In a hot environment, digesting lactose provides extra calories, simply because of the general lack of food.
In a cold environment, since food is naturally plentiful (fish and meats), lactose is more significant for its carbohydrate value, than for its caloric value (fish and meat are far more calorically dense than milk).
I think that the ability to obtain carbohydrates from lactose, in an otherwise carb-deficient environment, was a partial driver of the evolution of lactose digestion.
In a hot environment, digesting lactose provides extra calories, simply because of the general lack of food.
In a cold environment, since food is naturally plentiful (fish and meats), lactose is more significant for its carbohydrate value, than for its caloric value (fish and meat are far more calorically dense than milk).
I think that the ability to obtain carbohydrates from lactose, in an otherwise carb-deficient environment, was a partial driver of the evolution of lactose digestion.
