1 scoop of dry whey protein powder packs approx 118 cals in a 31g serving. The number of calories for that small serving size is considerably high, making whey powder a RED (high calorie density food)
On the other hand, a whey protein shake is actually 1 scoop dry powder blended with 250 ml of water. That makes it ~118 cals in a 250g serving (since water has no calories).
We have the same number of calories for a larger serving size now, making the whey protein shake a BLUE (low calorie density food)