Brooke Schantz, a registered dietitian at the Loyola University Health System near Chicago, said overeating healthy foods is easy to do, but the same rules apply to healthy food as junk food.
"While fruits are nutritious, too much of even a healthy food can lead to weight gain," Schantz said in a statement. "The key is to remember to control the portion sizes of the foods you consume."
Weight fluctuates based on a basic concept -- energy in versus energy out -- so if total caloric intake is higher than the energy you burn off during a day, people gain weight, Schantz said.
"If it is lower, you will lose weight," Schantz said in a statement. "I have had many patients tell me that they don't know why they are not losing weight. Then they report that they eat fruit all day long. They are almost always shocked when I advise them to watch the quantity of food they eat even if it is healthy."
There is one exception -- non-starchy vegetables are difficult to overeat unless they are accompanied by calories from sauces, cheeses and butter, Schantz said.
"This is due to the high water and fiber content of these vegetables coupled with the stretching capacity of the stomach," Schantz said. "But, limit vegetables high in starch, such as peas, corn and potatoes."