Increased nutrition and health are evolution every bit as much as genetic change. Evolution just means change.
I.e. a change in DNA within a population.
If a population moved from a location with scant food resources to one with abundant food resources - and as a result attained a larger average size - that would not be an example of evolution. Unless there was also a corresponding change in the DNA of the population that would take place over several generations (i.e. the abundant resources favor certain alleles that are advantageous only when nutrition is not limited).
Chinese children raised eating an American diet grow taller than thier parents or Chinese raised cohorts. They didn't “evolve” to be taller - they just got taller through better nutrition.