I couldn't find anything that wasn't paywalled on whey protein's elemental composition, and whey can be a variety of different substances at different concentrations anyway, but here are the ranges of concentrations for "average" proteins: Carbon: 50-55% Hydrogen: 6-7.3% Oxygen: 19-24% Nitrogen: 13-19% Sulfur: 0-4

For the purpose of ballparking the calculation, I'll assume whey has the following composition, which won't be too far off from its real composition: Carbon: 53% Hydrogen: 7% Oxygen: 22% Nitrogen: 17% Sulfur: 1%

So we get an average molecular weight of 12 X .53 + 1 X 0.07 + 16 X 0.22 + 14 X .17 + 32 X 0.01 = 12.65 grams per mole.

And an average molecular number of 6 X .53 + 1 X 0.07 + 8 X 0.22 + 7 X 0.17 + 16 X 0.01 = 6.36 protons per atom.

So 1 gram of protein would be 0.079 moles of our "average" element, and would contain 6.36 / 12.65 = 50.28% protons.

0.079 X 6.02 X 10²³ = 4.76 X 10^22, that's the number of nucleons. Multiplied by 50.28% protons you get 2.39 X 10²² protons in 1 gram of protein