Definition of "healthy"

By one o'clock the place was choc-a-bloc. […] The restaurant was packed, and the promenade between the two main courts and the subsidiary courts was thronged with healthy-looking youngish people, drawn to the Mecca of tennis from all parts of the country.

1935, George Goodchild, chapter 5, in Death on the Centre Court

Irregular bedtimes may disrupt healthy brain development in young children, according to a study of intelligence and sleeping habits. ¶ Going to bed at a different time each night affected girls more than boys, but both fared worse on mental tasks than children who had a set bedtime, researchers found.

2013 July 19, Ian Sample, “Irregular bedtimes may affect children's brains”, in The Guardian Weekly‎, volume 189, number 6, page 34

It was heretical to say that protein wasn't healthy, let alone say it promoted cancer.

2016, T. Colin Campbell, Thomas M. Campbell, The China Study, revised and expanded edition, BenBella Books, Inc., page 214