Total average isn't a good metric. We need to see a distribution graph over time. If the bell curve has flattened out, then that could be explained just with increasing obesity. If the entire graph has shifted left, then that's more likely an omnipresent environmental factor.
Total average isn't a good metric. We need to see a distribution graph over time. If the bell curve has flattened out, then that could be explained just with increasing obesity. If the entire graph has shifted left, then that's more likely an omnipresent environmental factor.