i don't believe all brands of whey protein are equal in weight.
table spoon is a volume measurement while gram is weight.
say want to know how many grams of protein in 4 tbsp of protein powder.
it's a 2-step conversion process. tablespoons are a volume measure, which relates to typical protein powder serving sizes, which are in cc, as follows:
1 cc = 0.0676280451 US tablespoons
so 4 tablespoons = 4/.06763 = 59.1 cc
now look at ur protein powder label & see how many grams protein are in what serving size (cc's) & convert.
say it's 25g protein in 70 cc, like ON whey, then you finish off the calculation as follows:
4 tbsp ON whey = 59.1*25/70 = 21.1g protein