In this LAB note
Question · Hypothesis · Method · Results · What Failed · What We Learned · What Changed at MOMS
Question
In a 16oz whole-food shake, which slot actually sets the fiber, the vegetables or the protein?
Hypothesis
We expected fiber to be an outcome of the vegetable slot. The Fruit and Vegetable slot is where the visible plant matter lives, so we assumed recipes carrying more grams of produce would carry more fiber, and that leafy greens would be the strongest single lever. We predicted a clear positive relationship between total Fruit and Vegetable grams and total fiber, and a weaker one for everything else.
Method
Published work on pulses (Mudryj, Yu and Aukema, 2014) reports that a half-cup serving of beans, chickpeas or lentils is among the densest routine fiber sources available in an ordinary diet, and Li and colleagues (2014) meta-analyzed 9 acute feeding trials showing that a single pulse serving measurably increases satiety. Internally, we pulled all 201 published MOMS recipes and parsed the ingredient grams out of every slot: Liquid, Body, Fruit and Vegetable, Protein, and Functional. For each recipe we summed total produce grams and total legume grams appearing in the Protein slot (chickpeas, lentils, black beans, kidney beans, adzuki beans, white beans, mung bean), then correlated each against the recipe's stated Fiber (g). We grouped recipes into legume-dose bands to look for a dose-response curve, and we tracked Carb (g) and Score in every band so that any fiber gain could be read against what it costs.
Results
The vegetable slot does not predict fiber. Total Fruit and Vegetable grams correlate with total fiber at r = 0.07, which is no relationship at all. Legume grams in the Protein slot correlate at r = 0.64. The dose response is clean across all 201 recipes: recipes with no legume (79 recipes) average 5.9g fiber; 1 to 39g of legume (46 recipes) average 7.9g; 40 to 69g (63 recipes) average 8.9g; 70g and above (13 recipes) average 10.7g. The unit conversion makes it concrete. Chickpeas appear in 75 of 201 recipes at an average of 39.4g, worth roughly 3.0g of fiber. Spinach appears in 21 recipes at an average of 26.6g, about one loosely packed cup, worth roughly 0.6g. To match one average chickpea portion using spinach alone you would need about 136g of raw leaves, roughly four and a half cups, inside a 16oz glass that is already holding 150 to 300ml of liquid and everything else. That volume does not exist. Two recipes show it directly. EI-W3-GUT-008-V1 Soft Center reads as a green shake, Spinach 30g plus Cabbage 45g, but its 10.4g of fiber comes mostly from Lentils 55g in the protein slot. WAY-W1-HYDRATE-008-V1 Even Waters carries Broccoli 45g and looks vegetable-forward, but its protein slot is Chicken 120g with no legume, and it lands at 2.5g fiber, the lowest in the entire database.
What Failed
Two things, and the second one matters more. First, simply adding a legume is not a fiber lever on its own. WAY-W4-RENEWAL-008-V1 Quiet Rebuild carries Chickpeas 30g in the protein slot and still comes in at 3.0g fiber, because the rest of the build (White Rice 19.5g, Seaweed 4g) contributes almost nothing. Dose and surrounding context both matter. Second, and more important: chasing fiber upward damages everything else. Past 40g of legume the average carb load climbs from 36.4g to 45.1g and then to 48.0g, while average Score falls from 15.3 to 14.8 to 14.2. Our three highest-scoring recipes in the whole database, EY-W4-CALM-001-V1 Quiet Recovery, EI-W2-WARM-001-V1 Cozy Glow, and EI-W2-WARM-002-V1 Inner Fire, all at Score 20, use egg white alone in the protein slot and sit at just 5.2 to 5.7g fiber. Fiber is a lever, not the objective. A version of this analysis that stopped at more legume, more fiber would have pushed us to formulate worse shakes.
What We Learned
Fiber in a whole-food shake is decided upstream of where people look for it. The vegetable slot governs color, micronutrients, flavor and volume, and it is doing real work, just not this work. The protein slot is where fiber is actually set, because legumes are the only ingredient class in our system that delivers meaningful protein and meaningful fiber in a portion that physically fits in a 16oz glass. The corollary is uncomfortable but useful: a shake's appearance is a poor predictor of its fiber in both directions. Green does not mean high fiber, and beige does not mean low.
What Changed at MOMS
We stopped treating fiber as a produce target and moved it into the protein-slot specification. Recipes now carry a default legume dose of 25 to 40g, the band that gained 2.0g of fiber over legume-free builds while holding the highest average Score of 15.3 and adding only about 1g of carb. Doses above 70g are now reserved for Meal Replacement builds where the carb headroom is deliberate. And when a recipe reads green but has no legume in the protein slot, that is now a flag in review rather than a finished formula: we check the fiber number against the protein slot before the recipe ships.
References
Mudryj AN, Yu N, Aukema HM. Nutritional and health benefits of pulses. Applied Physiology, Nutrition, and Metabolism, 39(11):1197-1204, 2014. | Li SS, Kendall CWC, de Souza RJ, et al. Dietary pulses, satiety and food intake: a systematic review and meta-analysis of acute feeding trials. Obesity, 22(8):1773-1780, 2014.
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