题目选项分析

Beets and carrots are higher in sugar than many other vegetables. They are also high on the glycemic index, a scale that measures the rate at which a food increases blood sugar levels. But while nutritionists usually advise people to avoid high-sugar and high-glycemic-index foods, despite any nutritional benefits they may confer, they are not very concerned about the consumption of beets and carrots.

Which of the following, if true, would best explain the nutritionists' lack of concern?

【选项】Nutritionists have only recently come to understand that a food's effect on blood sugar levels is an important determinant of that food`s impact on a person's health.