Why paleo excludes soy milk
Paleo excludes by category rather than by macro: grains, legumes, dairy, refined sugar, and seed oils are out regardless of how nutritious they might be otherwise. Paleo eaters typically reach for meat, fish, eggs, vegetables, fruit, nuts, seeds, and animal-derived fats as the foundation of any meal.
Soy Milk falls outside the paleo framework and is typically avoided. The classification rests on category of origin, since paleo excludes grains, legumes, dairy, refined sugar, and seed oils regardless of preparation — soy milk is either a grain, legume, dairy product, refined sugar, or industrial seed-oil product — all categories paleo excludes regardless of preparation.
Reading the package
On the nutrition panel and ingredient list, the relevant signals are grains, legume-derived ingredients, dairy, refined sugar, and industrial seed oils.
How paleo eaters handle this
For paleo eaters, the practical question with soy milk is usually which substitute fits best in the meals where it would normally appear.
This is reference-only classification content and does not constitute medical or dietary advice.