In this LAB note
Question · Hypothesis · Method · Results · What Failed · What We Learned · What Changed at MOMS
Question
Egg white is the single heaviest ingredient in 98 of our 201 recipes, at an average of 199.8 grams. Egg white is also 88 percent water. So what is that 200 grams actually delivering to the shake — protein, or liquid?
Hypothesis
We expected the protein slot to behave like a protein slot: grams in, protein out, with weight roughly tracking protein contribution. On that assumption a 200-gram ingredient should be doing several times the protein work of a 40-gram one. We also expected that if egg white were mostly water, our own formulation system would already be compensating for it — pulling down the liquid slot in recipes that lean on egg white, so the finished shake did not end up thinner than intended.
Method
We pulled all 201 recipes from the MOMS formulation database and parsed the protein slot of each into individual ingredients with their gram weights, then compared every ingredient's average dose against the shake's finished macros and against its liquid-slot volume. Reference composition for raw egg white is USDA's: 88 percent water, 10.9 g protein and 52 kcal per 100 g, with negligible fat and no fiber. For the absorption question we used two human ileal-digestibility studies. Evenepoel and colleagues (1998) measured true ileal digestibility of 13C- and 15N-labeled egg protein in ileostomy patients after a 25 g test meal, given in cooked and in raw form. Kashyap and colleagues (2018) measured true ileal indispensable amino acid digestibility of intrinsically labeled egg white protein in Indian adults using a dual stable isotope tracer method.
Results
Egg white appears in 98 of 201 recipes at a mean dose of 199.8 g, ranging from 95 g to 240 g. Every other ingredient in the protein slot is a fraction of that weight: chickpeas average 39.4 g, lentils 40.4 g, tofu 45.8 g, black beans 52.4 g, chicken 80.7 g. At USDA composition, 200 g of egg white is roughly 176 g of water, 21.8 g of protein, 104 kcal and about 0.3 g of fat. The cleanest case is EI-W1-CLEANSE-017-V1 ("Slow Clean", Filling), where Egg White 240 g is the entire protein slot. That 240 g supplies about 26 g of the shake's 32.1 g of total protein, close to 82 percent of it, and carries roughly 211 g of water in with it. The liquid slot of that same recipe is Oat Milk 182.7 ml. The protein slot is putting more water into the blender than the liquid slot is. Its neighbours show the same division of labour. EI-W1-CLEANSE-001-V1 ("Quiet Cleanse") uses Chickpeas 30 g + Lentils 30 g + Egg White 240 g and finishes at 32.5 g protein, 313.2 kcal and 6.4 g fiber. EI-W1-CLEANSE-016-V1 ("Barely There Cleanse") uses Lentils 55 g + Egg White 240 g for 32.0 g protein, 298.1 kcal and 7.1 g fiber. In both, 60 g or less of legume is doing the fiber work while 240 g of egg white does the protein work — four times the weight, and no fiber at all. For contrast, WAI-W2-PROTEIN-008-V1 ("Muscle Renew") reaches 48.2 g of protein from Chicken 150 g. Chicken is the denser carrier: fewer grams, more protein, and roughly 100 g of water brought along rather than 211 g.
What Failed
Two things failed, and the second matters more than the first. Our compensation hypothesis is simply wrong. Across all 201 recipes the correlation between egg white grams and liquid-slot volume is -0.05, which is statistically nothing. Recipes containing egg white average 224 ml in the liquid slot; recipes without it average 234 ml. A 10 ml gap comes nowhere near accounting for the roughly 176 g of water arriving through the protein slot. "Slow Clean" happening to have a below-average 182.7 ml liquid slot is one recipe, not a pattern, and we should not read intent into it. Our own system was not treating egg white as a water source at all. We found a gap, not a design. Second, the protein figure we attach to egg white is conditional on heat, and our database does not record heat. Evenepoel and colleagues measured true ileal digestibility of cooked egg protein at 90.9 plus or minus 0.8 percent, and of raw egg protein at 51.3 plus or minus 9.8 percent. Kashyap and colleagues measured cooked egg white protein at 86.3 plus or minus 4.6 percent. Both studies are small — the 1998 one used five ileostomy patients — so the exact percentages should be held loosely. The direction is not in doubt: 26 g of egg white protein on a spreadsheet is not 26 g of absorbed protein unless that egg white has been heat-treated. We record grams of ingredient, not processing state, so at present we cannot tell from the database which of those 98 recipes clear the bar.
What We Learned
Weight in the protein slot is not a proxy for protein. The heaviest single thing in half our shakes is mostly water, and the lightest things sharing that slot — 30 g of lentils, 40 g of chickpeas — are there for fiber, not for protein. Splitting a recipe into a protein slot and a liquid slot hid the fact that in those 98 recipes the protein slot is also the largest single source of liquid. The second lesson is narrower and less comfortable. A protein gram on a formulation sheet is a claim about composition. Absorption is a separate claim, and the processing step sits between the two. We had been treating the first as though it settled the second.
What Changed at MOMS
We now compute a total free-water figure for every recipe — the liquid slot plus the water carried in by egg white, Greek yogurt and other high-moisture protein ingredients — and hold that combined number, rather than the liquid slot alone, against the texture target for each Cal Label. In practice that means recipes carrying 200 g or more of egg white have their liquid slot trimmed rather than left at the default. We have also added a processing-state field to the protein slot, so egg white is specified as pasteurized or cooked rather than simply "egg white", and we have flagged the raw-versus-heated digestibility gap for review before we quote protein figures drawn from those recipes.
References
Evenepoel P, Geypens B, Luypaerts A, Hiele M, Ghoos Y, Rutgeerts P. Digestibility of Cooked and Raw Egg Protein in Humans as Assessed by Stable Isotope Techniques. Journal of Nutrition, 128(10):1716-1722, 1998. | Kashyap S, Shivakumar N, Varkey A, Duraisamy R, Thomas T, Preston T, Devi S, et al. Ileal digestibility of intrinsically labeled hen's egg and meat protein determined with the dual stable isotope tracer method in Indian adults. American Journal of Clinical Nutrition, 108(5):980-987, 2018.
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