I used it to eliminate an afternoon shake, (25 Grams of Protein and 120 Calories) did not notice any difference in mass or training so I was happy with the HumaPro.
just looked at the humapro label... interesting that they don't list a calorie amount???? amino acids contain energy * for sure* - the 3 bcaa are -
leucine: 4.65 calories per gram
isoleucine: 4.65 calories per gram
valine: 4.64 calories per gram
for example.
the label is using fda loophole - indiv aminos can not be used as a "protein" declaration see 21cfr111:101.36 -
"protein shall not be declared on labels of products that...contain only individual amino acids"
https://www.accessdata.fda.gov/scripts/cdrh/cfdocs/cfcfr/CFRSearch.cfm?fr=101.36
and if it therefore contains no protein (or carbs or fat - n/a for amino only product), it contains no calories - 21cfr111:101.9 -
https://www.accessdata.fda.gov/scripts/cdrh/cfdocs/cfcfr/cfrsearch.cfm?fr=101.9
you were saving *some* energy, but with an allowed fda 20% error rate - not much. i'd stick to the whey (isolate if you want fewest calories). we eat way more protein than needed anyway - thats why you probably didnt notice a difference (and "muscle loss" is way over-blown too, imo).