The sun is a point light source that is very harsh and unflattering. Most of the lighting work that takes place outdoors is an attempt to soften the harsh sunlight and/or fill in the dark  shadows. As you can see in the scene at the right, the sun can be a real problem. A few possible solutions:

1) One simple solution is a bounce card or reflector (which was demonstrated earlier in this lesson). If properly angled, it will fill in the shadowy areas.

2) Another option would be to use artificial lights to fill in the shadowy areas. Because the sun is so bright, artificial lights must be very large to have an impact outdoors. (For example, think of how little effect car headlights have in the daytime.)

3) A third solution would be to move your subject to a nearby shady location.

4) In a pinch, simply turning the subject so the sun hits him from behind would at least reduce the harsh side shadows... and create something of a back light.