proteins是什么意思？

As part of the Kids Live Well campaign-expected to be announced nationwide Wednesday—participating restaurants must promise to offer at least one children's meal that has fewer than 600 calories(卡路里), no soft drinks and at least two items from the following food groups: fruits, vegetables, whole grains, lean proteins or low-fat dairy.

When they detect an extended dry period, they divert their metabolisms, producing sugars and certain stress- associated proteins and other materials in their tissues.