Remove most of the obstacle, and the improvement tracks proportionally. That formula holds everywhere — clear three-quarters of a blockage, and roughly three-quarters of the flow returns.
Sprouting makes the same promise for plant protein. Soak the lentils, germinate the beans, strip away the compounds that interfere with digestion — and the protein should absorb proportionally better. Whether soaking or sprouting actually improves plant protein hinges on a ratio most people skip: how much obstacle disappears versus how much improvement arrives.
Does Soaking or Sprouting Improve Plant Protein?
Sprouting reduces key antinutritional compounds dramatically — phytic acid by up to 76%, trypsin inhibitors by up to 39%. But protein digestibility improves only 1–4% across three of four legume types, and peas slightly declined. Meanwhile, saponin levels increased up to 27-fold. The improvement exists but falls far short of what the antinutrient reductions suggest.
— Yilmaz Tuncel et al. 2025 · Food Sci. Nutr. · 4 pulse types, in vitro
The obstacle-removal side of the equation is genuinely impressive. A 2025 germination study tested four legumes — chickpeas, lentils, peas, and mung beans — and measured what 48 hours of sprouting did to the compounds that block protein digestion. Phytic acid, the most studied of those compounds, fell by up to 76% in lentils. Trypsin inhibitors — molecules that latch onto digestive enzymes and prevent them from breaking protein apart — dropped up to 39% in mung beans.
Those numbers read like the formula working. Remove three-quarters of the primary blocker, cut another by more than a third, and the protein should follow.
The protein digestibility improvement that followed all of that: up to 4.4%.
After 76% of the phytic acid and 39% of the trypsin inhibitors disappeared, the actual change in how completely the protein breaks down landed in single digits. Chickpeas gained 4.4%. Lentils, 3.8%. Mung beans, 4.4%. And peas — the legume with the highest protein digestibility at baseline — declined 2.3%.
Then a second cost surfaced. Saponins, another group of compounds that interfere with nutrient absorption, did not decline with sprouting. In mung beans, saponin levels rose 27-fold — from a trace amount to a concentration that dominated the antinutritional profile. Sprouting did not clear the field. It rearranged it.
The disconnect resolves once digestibility stops being treated as a one-variable problem. Phytic acid is one of at least five compound groups — including trypsin inhibitors, lectins, tannins, and fiber structure — that affect how thoroughly the body breaks down plant protein. Removing most of one compound does not open a door with five locks.
The measurement carries a caveat that matters: these digestibility changes were quantified using enzymes in a laboratory, not inside a human digestive system. The method simulates digestion well enough to compare legumes against each other, but it cannot predict exactly how much more protein a person would extract from a sprouted lentil over the course of a real meal.
Sprouting is not wasted effort. For chickpeas, lentils, and mung beans, 48 hours of germination nudges digestibility upward — modestly, and with a saponin trade-off the supplement label will not mention. But the preparation-method question was always a smaller question inside a larger one — what determines whether plant protein actually builds muscle runs through factors the sprouting debate never reaches.