A key component of good health is understanding portion sizes. Eating the right amount of food will keep you at a healthy weight and may help you loose weight if you are overeating on a regular basis. Here are some links with information about portions sizes.
A Quick and Easy Way to Determine Portion Size: http://www.livestrong.com/blog/a-quick-and-easy-way-to-estimate-portion-size
8 Tips for Controling Portion Sizes: http://www.health.com/health/gallery/0,,20405321,00.html
Portion Size Pitfalls: http://www.choosemyplate.gov/weight-management-calories/weight-management/better-choices/decrease-portions.html
Servings Size vs. Portion Size: http://www.livestrong.com/article/409307-serving-size-vs-portion-size
Serving Sizes: http://on.aol.com/video/food-serving-sizes-vs--reality-518022229
What does 200 calories look like? http://www.wisegeek.com/what-does-200-calories-look-like.htm