That's not the meaning of the word "natural" in the context of nutrition, from my understanding. Perhaps the word you're looking for is "traditional".
Semantics aside, I'll gladly grant you that lard is a food that has been eaten in the past. But, once again, that doesn't mean it's necessarily better than other foods that haven't been eaten in the past.
An good example is "golden" rice. An argument could be made (and has been made) that golden rice could save millions of people from devastating vitamin deficiency which they would continue suffer from were they to avoid golden rice for their "traditional" foods.
Plenty of traditional foods just aren't very nutritious or healthy.
I know that HNers will scoff at the citing of popular literature, but I find the arguments in "Diet for a Small Planet" and "In Defense of Food" quite compelling when it comes to "traditional" foods. Traditional diets are developed to make best use of the ingredients available in a region and are often the healthier than "scientific" diets. A good example is Mexican food. Corn and beans together make a complete protein.
I think that tradition, like cuisines, is an ever changing thing, however.
Semantics aside, I'll gladly grant you that lard is a food that has been eaten in the past. But, once again, that doesn't mean it's necessarily better than other foods that haven't been eaten in the past.
An good example is "golden" rice. An argument could be made (and has been made) that golden rice could save millions of people from devastating vitamin deficiency which they would continue suffer from were they to avoid golden rice for their "traditional" foods.
Plenty of traditional foods just aren't very nutritious or healthy.