It used to be that a population’s wealth was a good indicator of how tall and how much its citizens weighed. That’s not the case anymore. In the past, the wealthier individuals were almost always significantly taller than their poorer counterparts. For instance, in the late 1700’s the height difference between the rich and the poor was almost nine full inches.
In spite of the bombardment of news articles, its not even the quality of healthcare that helps a population grow taller. If there was such a direct link between height and healthcare quality, then it would be true that worldwide height would match up even halfway with the vast expansion of increased healthcare in countries that were previously all-but-void of modern vaccinations and other preventative medical care.
To further drive the point home that medical healthcare doesn’t equate to population height, consider that the drop-off decline of American height took place in the last half of the 20th centure - during the great majority of which U.S. healthcare was considered to be the best in the world.