The plant milk section has grown from a single soy carton to an entire refrigerator case, and the four most common options differ enough in protein, sugar, and fat that "plant milk" is really more of a category than a single nutritional profile.
Protein is where they differ most
Soy milk is the only plant milk that comes close to dairy's protein content, at roughly 7-8 grams per cup. Oat milk usually lands in the middle, around 2-4 grams, while almond and coconut milk typically have 1 gram or less unless the brand fortifies it — worth knowing if you're counting on your morning glass for protein rather than just flavor in coffee or cereal.
Check the carton for added sugar
"Original" and "vanilla" versions of any plant milk usually carry added sugar that the plain or unsweetened version doesn't — sometimes 7 grams or more per cup, on top of whatever carbohydrate the milk naturally has. Unsweetened is the safer default if you're watching blood sugar or added sugar generally.
Oat milk and its natural carb content
Even unsweetened, oat milk runs higher in carbohydrate than almond or soy milk because it's made from a grain rather than a legume or nut. That's not a reason to avoid it, but it's worth knowing if you're drinking it by the glass rather than using a splash in coffee.
Calcium and vitamin D fortification
None of these milks are naturally rich in calcium or vitamin D the way dairy milk is, so nearly all commercial versions are fortified to match dairy's levels — but fortification varies by brand and product line, and it's worth checking the label rather than assuming every carton on the shelf carries the same amount. Homemade or minimally processed plant milks, including some sold at natural food stores, often skip fortification entirely, which matters if the milk is a meaningful part of your calcium intake.
What about saturated fat?
Coconut milk beverage is the outlier on fat: unlike the others, which are low in saturated fat, coconut-based milk carries a meaningful amount, since coconut itself is one of the few plant sources high in saturated fat. It's a different fat profile from butter or animal fat, but it's still worth factoring into a cholesterol-conscious diet rather than assuming "plant-based" automatically means low in saturated fat across the board.
Picking one for your goals
Soy is the closest swap for dairy protein, almond is the lowest in calories and carbs, oat is creamiest for coffee, and coconut milk beverage (not the canned kind) is fine in moderation but brings little protein and more saturated fat than the others — read the label rather than assuming any of them is automatically the healthy choice.
There's no requirement to settle on just one. Many people keep two on hand: something creamy like oat for coffee, where a splash doesn't need to carry any nutritional weight, and something higher in protein like soy for a glass on its own or a smoothie base, where the nutrition actually matters. Matching the milk to the use case tends to work better than searching for one option that's simultaneously the best at everything.
Whichever you choose, giving the carton a shake before pouring matters more with plant milks than with dairy, since many separate slightly in the fridge and the last pour from an unshaken carton can taste noticeably thinner or more watery than the first.
Shelf-stable cartons versus refrigerated versions of the same plant milk can also differ slightly in processing, since shelf-stable versions go through ultra-high-temperature treatment for a longer unrefrigerated shelf life, which some people find changes the flavor modestly compared to the refrigerated version of the same product. Neither is a health concern, but it's worth trying both if a plant milk you've tried once didn't taste quite right, since the other format might.
For cooking and baking specifically, unsweetened soy or oat milk tend to substitute most reliably for dairy milk in a recipe, since almond and coconut milk's thinner consistency and more distinct flavor can change the result more noticeably in something like a baked good or a cream sauce. Testing a new plant milk in coffee first, before committing it to a full recipe, is a low-stakes way to judge whether it's the right fit.
Homemade versions, particularly of oat or almond milk, are simple enough to make with a blender and a nut milk bag or fine strainer, and they give full control over sweetness and additives — most commercial plant milks also contain gums or stabilizers to keep the liquid from separating, which a homemade version skips entirely. This isn't necessary for most people, but it's worth knowing as an option for anyone sensitive to those additives or simply curious about a fresher-tasting version.
Whichever version ends up in the fridge, checking the expiration date and giving it a sniff before use matters more with plant milks than some people expect, since an opened carton typically has a shorter usable window than dairy milk once air exposure begins the spoilage process.
