Americans aren't eating enough fruits and vegetables, according to a researcher who studies food as medicine.Getty ImagesAmericans' diets have remained largely unchanged since 1999, according to a new study.Meals remain high in processed foods that can increase a person's risk of disease.Ditching sugary drinks and eating two fewer processed meals a week could help.Americans are eating healthier than in previous years, but they still have a long way to go, according to a researcher who studies food as medicine.Dr.