The change in protein grams per serving (from 24g to 15g) is simply due to a decrease in the serving size itself. If you notice the scoop size is smaller in new canisters versus old canisters. For example, our old/former Chocolate Rice Protein provided 25g protein in a 34g serving (1 large scoop). You can get 25g of protein by using 1 and a half small scoops in the New Premium Chocolate rice which is approximately a 33g serving–and about as much as the old scoop size/serving.
The serving size was lowered to make it easier to tailor to individual protein needs as not everyone needs a 24g protein per day, though you can still get this by simply using 1.5 scoops. Now you can get as little or as much protein as YOU individually need: 15g (1 scoop); 23-24g (1.5 scoops); and 30g (2 scoops).