Sforno on Numbers 13:32/ספורנו על במדבר י״ג:ל״ב

1ארץ אוכלת יושביה, even though the people living there are strong, this is not a compliment to the land; rather it means that it is only due to their exceptionally hardy constitution that they were able to survive in that land. Ordinary people would die there because the climate is so hard to take.