Subjects can also be facing the sun and they will not end up squinting, also there will be no real shadows under the nose or neck, giving you the perfect opportunity to shoot portraits without having to use any artificial lighting or complex setups.
1. You could either use a reflector to bounce the light back on to the subject or
2. Shoot in the shade and compensate the under exposure using artificial lighting from an on camera flash, off camera flash or a strobe.
The video below talks about using a reflector to get the job done. I highly recommend this approach for the main reason that it is easy to do and simple to set up, while at the same time being relatively inexpensive.
The difference is very evident and makes the little effort all the more worthwhile. Try it out and let me know how it worked for you. Keep in mind that sometimes, finding the right angle to bounce the light back onto the subject takes a bit of practice and if it's windy outside, then getting your assistant to hold the reflector steady can be a challenge on its own.