Summer is a popular season for diets. People want to look good at the beach or lose the pounds they gained while on vacation. Most doctors caution that fad diets don’t work for the long term. Instead they stress lifestyle choices – eating plenty of fruits and vegetables and getting enough exercise and sleep. New findings of a Harvard University project confirmed this. But the researchers also found it’s not just a matter of calories consumed versus calories burned. Certain foods, such as potatoes, can cause more weight gain over the years. Others can help keep people lean. Diane and her guests explore the relationship between food choice and weight.