The only common pulse with complete protein — and the one with real caveats.
Soybean is nutritionally unusual among pulses. It contains all nine essential amino
acids in useful amounts, which almost no other plant food does, and it is far higher in
protein and fat than any other bean here.
It also attracts more argument than any
other food in this category. Most of that argument is louder than the evidence supports, but
soy is genuinely different enough from other pulses that it deserves its own
consideration.
Per 100g dry. Soy is far higher in protein and fat than any other pulse on this site.
Based on the nutrients and fibre this food supplies. These are supporting foods, not treatments.
It must be cooked thoroughly. Raw soybeans contain trypsin
inhibitors that interfere with protein digestion. Proper cooking destroys them.
Soak overnight and pressure cook 8–10 whistles. Soy is hard and takes
longer than almost anything.
Fermented soy is easier. Tempeh, miso and
natto are more digestible than plain cooked beans, because fermentation has already broken
down much of what makes soy hard work.
Whole soy over isolates. Soy
flour, tofu and tempeh behave differently from highly processed soy protein isolate in
ultra-processed foods. Prefer the former.
Complete protein is what sets soy apart. Most pulses are low in methionine, which is
why dal is traditionally eaten with rice or roti — the grain supplies what the pulse
lacks. Soy does not need that pairing.
Soy's cholesterol effect has been studied
extensively enough that several regulators permit a health claim for it. The mechanism appears
to involve both the protein itself and the soluble fibre, though the effect size in most
trials is modest.
Thyroid conditions: soy can interfere with absorption of thyroid
medication. Leave several hours between your tablet and a soy-heavy meal, and tell your
doctor.
Soy allergy is among the more common food allergies —
avoid entirely if diagnosed.
Gout: soy is moderate in purines.
Kidney disease: pulses are high in potassium and
phosphorus, and protein often needs limiting. This needs your doctor's numbers, not a general
rule.
IBS: pulses are high-FODMAP. Small, well-soaked, well-cooked
portions are tolerated far better than large ones.
Gout: pulses
contain moderate purines, though plant purines appear to be much less of a problem than those
from meat and seafood. If you flare after dal, trust your own pattern.
This is information, not a prescription. If you are managing a diagnosed condition or taking medication, talk to your doctor before making a large change to your diet.
Nutrition figures on this page come from standard food composition data. These links let you check the numbers and read the underlying research yourself rather than taking our word for it.