Best Plant Milk: How They Compare (Honest Guide)

There is no single best plant milk. The right one depends on your goal. Soy and pea come closest to cow's milk for protein, almond and coconut are the lowest in calories, and oat brings fiber and the best barista texture. Whichever you choose, the decision that matters most is buying an unsweetened, fortified version and reading the label, because brands vary far more than the category names suggest.

How do the main plant milks compare per cup?

The biggest real difference between plant milks is protein, and it is large. A 2022 peer-reviewed study in Frontiers in Nutrition measured protein per 100 ml at 3.78 g for soy and 3.26 g for cow's milk, but just 1.02 g for almond, 0.46 g for oat, 0.32 g for coconut and 0.17 g for rice. Translated to a US one-cup serving, soy lands around 7-8 g, cow's milk about 8 g, oat 2-3 g, almond about 1 g, and rice and coconut under a gram. Soy was the only plant milk to match cow's-milk protein quantity.

Which plant milk has the most protein?

Soy, and it is the only plant milk that genuinely matches cow's milk for protein quantity. Pea milk is the close non-soy rival at 7+ g per serving, which is why Harvard Health groups it with soy as a high-protein choice. One honest limit applies here: even soy's protein scored lower on digestibility and amino-acid quality than dairy in the Frontiers study, so plant protein is not identical to dairy protein gram-for-gram. Among nut and grain milks, almond, oat, coconut and rice all fall far short, unsweetened almond milk supplies about 1 g per cup versus dairy's 8 g, per UF/IFAS extension figures. If protein is your priority, soy and pea are the answer; nut milks are not protein drinks.

Which is the lowest-calorie plant milk?

Unsweetened almond and coconut are the lowest-calorie options. The Frontiers data put almond at 32.8 kcal and coconut at 23 kcal per 100 ml, the two lowest of the milks measured, with soy at 41.6, oat at 41.5 and rice at 54.6. UF/IFAS lists unsweetened almond milk at roughly 30 calories per cup. The catch is that "low calorie" usually means "low protein," so almond and coconut suit people watching calories or using milk mainly to lighten coffee, not those leaning on milk for nutrition. This is also where reading the label matters: flavored and sweetened versions can carry far more sugar and calories than the unsweetened base.

Which plant milk is best for fiber and heart health?

Oat is the standout for fiber, and soy and oat are both recognized for heart and environmental benefits. Unsweetened oat milk carries about 2 g of fiber per cup including beta-glucan, the soluble fiber shown to lower LDL cholesterol, a real advantage over cow's milk, which has none. The honest limit, flagged directly by UF/IFAS, is that it may be difficult to consume enough beta-glucan from oat milk to get that cholesterol effect, so oat milk should not be treated as a proven cholesterol treatment. Harvard's nutrition experts highlight soy and oat for both cardiovascular and planetary benefits, while cautioning that the gains depend on choosing fortified, low-sugar products.

Where does pistachio milk fit in?

Pistachio milk sits in the middle: Harvard Health describes it as a bit higher in protein than most other plant milks, typically under 100 calories per cup, but notes that commercial versions contain little actual pistachio, so you miss most of the whole nut's thiamin, manganese and B6. It is a pleasant, mild choice rather than a nutritional powerhouse. If you want the real-nut nutrition, making it yourself gets you closer; our guide to how to make pistachio milk and the deeper looks at pistachio milk benefits and pistachio milk protein cover what the homemade version actually delivers. For head-to-head detail, see pistachio milk vs almond milk, vs oat and vs soy.

Why does fortification matter more than the base ingredient?

Because plant milks are naturally low in calcium, vitamin D and B12, fortification, not the nut, grain or bean itself, decides whether a plant milk approaches cow's milk on those nutrients. A US market survey in the Journal of the Academy of Nutrition and Dietetics found only about 76% of oat, 69% of soy and 66% of almond products were fortified with both calcium and vitamin D, meaning roughly a third are not. The Frontiers study also notes soy still trails cow's milk on iodine and B12 unless fortified. Harvard guidance is consistent: choose unsweetened, fortified products and keep added sugar under about 10 g per serving. The label is the deciding document here, not the category name.

A note on children and infants

Plant milks are not a like-for-like replacement for breast milk or infant formula. Per the NHS, rice drinks should not be given to children under five because of their arsenic content, a caution echoed by the FDA's work on inorganic arsenic in rice products. The NHS says unsweetened, calcium-fortified soya, oat or almond drinks are acceptable from age one, and for toddlers, soy or oat are generally preferred over nut milks for protein. If a young child relies on a plant milk, discuss it with a health visitor or pediatrician first.

So there is no flat winner. Match the milk to the job: soy or pea for protein, almond or coconut for fewest calories, oat for fiber and foam, and always unsweetened and fortified. To go deeper on any single pairing, browse the full set of pistachio milk comparisons, or see our rundown of the best pistachio milk brands.

Allergy note

Almond, cashew, pistachio and other nut milks are tree-nut products and are unsuitable for anyone with a tree-nut allergy. Soy milk is one of the major food allergens and should be avoided by those with a soy allergy. Oat, rice, pea and coconut milks are typically free of nuts and dairy, but always check the label, as shared production lines and added ingredients vary by brand. Most of the plant milks here are dairy-free and vegan, which makes them useful swaps for lactose intolerance, but a plant milk being dairy-free does not make it allergen-free.