And different populations evolutionarily "fine-tuned" in environments with different availabilities of various foodstuffs. While many dietary requirements are common to all humans (e.g. we lost the ability to synthesise vitamin C, making us all susceptible to scurvy), some are specific to individuals and (genetically-related) families.

Diet is one of the very few places where your genetic ancestry actually matters – although your gut microbiome, which evolves faster (https://doi.org/10.3389/fmicb.2014.00587), may not share quite the same ancestry as your human cell tissue.

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throwaway198846 3 hours ago | parent [-]

> Diet is one of the very few places where your genetic ancestry actually matters

Aside from lactose intolerance what else is different between humans?

	▲	adrian_b 3 hours ago \| parent [-]
		There are many other intolerances, e.g. coeliac disease and the many different kinds of food allergies. Besides these cases, which are obvious due to immediate harm, and which are the reason for laws about food labeling that mentions lactose, gluten and various allergens, there is a lot of variability between humans in the efficiency of digesting various foods and in the capacity of absorption for various nutrients. Some people are able to eat pretty much anything, while others are aware that they do not feel well after eating certain things, so they avoid them.