Strengthening Dietary Recommendations

A health expert recently suggested that consuming a diet rich in fruits and vegetables can lower the risk of developing chronic diseases. While many nutritionists support this idea, critics argue that people can maintain a healthy lifestyle regardless of their dietary choices by focusing on regular exercise.

The health expert counters that while exercise is beneficial, it cannot compensate for the absence of essential nutrients that a balanced diet provides. Thus, the expert concludes that changing one's diet is necessary for reducing chronic disease risk.

Which of the following, if true, would most strengthen the health expert's argument?