Oatly oat milk at a grocery store in Chicago. | Scott Olson/Getty Images
The unhelpful, distracting debate about whether oat milk is bad for you totally misses the point.
Is oat milk good or bad for you?
That’s the question a bunch of recent news headlines have asked. I really hate that question.
Obviously, how the food we eat affects our health is very important. But most foods — including nondairy milks — are not universally good or bad for everyone. Whether or not oat milk is bad for your health depends on a lot of things: your current body condition, the context in which you’re consuming it, and how much of it you’re drinking, to name a few.
“Simple ‘good or bad’ stories about traditional milk or nondairy milks, such as oat milk, often overlook the complexity of nutrition,” Hassan Vatanparast, a professor of nutrition at the University of Saskatchewan who has studied non-dairy milks, told me over email.
This healthy/unhealthy dichotomy also obscures a much more complicated set of factors that determine what we eat. For many of us, health is high on that list. But so is taste, cost, presence of allergens, and environmental impact. We live in a time that begs us to think beyond ourselves, beyond our bodies, and to recognize that what we eat affects the world around us — often in very serious ways.
So, what should we drink? That question has been gnawing at me, and so I read some things and talked to some experts to try to figure it out.
If you’re a healthy person, a daily oat milk latte is not a problem
Many recent stories about oat milk raise concerns about the drink’s effect on blood sugar — more specifically, that it causes a spike in blood sugar following consumption. So let’s start there.
Repeated spikes in blood sugar (i.e., a fast build-up of glucose in your blood) are famously not good. It’s linked to cardiovascular disease and insulin resistance, a precursor to diabetes. What does oat milk have to do with it? It’s higher in starch (a carb) than some other nondairy milks, and starch is converted into simple sugars when you digest it. That raises your blood sugar. (This conversion of starch to more simple sugars also happens when oats are processed into oat milk, which is why oat milk often tastes somewhat sweet, even if sugar isn’t listed as an ingredient.)
But it’s normal for food to raise your blood sugar, especially if that food is a processed grain. For most people, that won’t be a problem. If you’re healthy and not loading your diet with starchy carbs, you should have no problem regulating your blood sugar after a cup of oat milk and bringing glucose levels back down after a spike. To be clear, oat milk is not a sugary drink like, say, soda.
Going a bit deeper: Nutritionists use a rating system called the glycemic index to measure how quickly different foods raise our blood sugar (which is different from just the total amount of sugar in something because different kinds of sugar have different effects on blood sugar — it’s confusing). In general, oat milk has only a “moderate” glycemic index, Vatanparast told me. That means it’s not particularly bad for blood sugar or particularly good.
I asked the oat milk company Oatly about this, too. The company’s nutrition specialist, Kate Twine, said that its popular Barista Edition, which is slightly fattier than regular Oatly, has a medium glycemic index. If you factor in the serving size (e.g., one cup), using a related measure called glycemic load, the blood sugar profile is even better — the glycemic load is “low,” she said.
One somewhat obvious takeaway is that the amount of milk (and thus carbs) you’re drinking matters. What you’re consuming with it matters, too. Foods high in fiber, protein, and fat can blunt the impact on blood sugar because they slow down the absorption of glucose. (Cow’s milk has a lower glycemic index than oat milk and other nondairy milks, but a more comparable glycemic load. Rice milk, meanwhile, has a very high glycemic index and load. The bottom line: A cup of oat milk is probably not going to be a problem for blood sugar.)
But there’s an important caveat: For people with diabetes or insulin resistance, glucose — and the presence of starchy carbs — obviously matters a lot more. “If you have diabetes, oat milk may not be the best option since it’s one of the higher carbohydrate-containing milk substitutes,” Marion Groetch, a registered dietitian and director of nutrition services at Jaffe Food Allergy Institute, a division of the Icahn School of Medicine at Mount Sinai, told me. But if you’re not diabetic and otherwise eat well, Groetch said, there’s not much of a concern with having an oat milk latte every day.
Some other health-related considerations:
Oat milk tends to be lower in protein, compared to dairy and soy milk. But you probably don’t have to worry about that.
These milks are typically higher in fiber and lower in fat than dairy and some other nondairy milks, such as coconut (assuming you avoid full-fat options or those with added sugar).
Additives like rapeseed oil and emulsifiers (which essentially prevent the ingredients from separating), common among nondairy milks including oat milk, are generally recognized as safe by national and international health authorities, Vatanparast said.
That said, there’s some research linking emulsifiers — and especially synthetic emulsifiers like carboxymethylcellulose and polysorbate 80 — to potentially harmful changes in the gut microbiome. The real-world implications are not clear or well-tested. The studies I read suggest that there aren’t serious safety concerns with the emulsifiers used by popular oat milk brands (I reviewed several), such as gellan gum, though more research is needed.
So, where does that leave us? Drinking oat milk is probably fine for your body unless you’re drinking large quantities of it, already loading your diet with carbs, and/or diabetic. If most of your day’s liquid is coming from any milk, plant-based or not, that’s probably not great. Moderation is key.
The other reason why you might consider a milk “good” or “bad”
Now is a good time to mention: I’m not vegan, I occasionally eat dairy, and I don’t really love any of the nondairy milks. They’re all kind of eh. But I typically choose to consume oat and soy milks because they taste good enough in coffee and cereal, I can afford them, and, importantly, it’s an easy way to support the welfare of cows and reduce my carbon footprint.
That’s another reason why I find the “is it good vs. bad for you” debate over oat milk kind of icky: It distracts from these other important considerations, catering instead to the public’s desire for simple, comfortable answers. I want choosing something as basic as milk to be simple, but it’s not.
My personal perspective is that I like cows, and the treatment they receive at a typical dairy seems, at best, unkind. Farmers repeatedly impregnate cows and take away their calves right after they’re born. If those babies are male, they are usually turned into veal or raised for beef. If they’re female, the calves are typically dehorned and docked, and also eventually slaughtered (when their milk production wanes). I’m having trouble imagining that this is a happy existence.
I’m also aware that, globally, a liter of dairy milk produces around three times as much carbon emissions as the same amount of plant-based milk. Cows release methane, a potent greenhouse gas, through their burps and manure. The chart below, drawing on a 2018 study from the journal Science, is especially revealing. It shows that nondairy milks — and especially oat milk — not only release fewer emissions but also require less land and water. They tend to pollute less, too. (Growing feed for cows requires a lot of land, fertilizers, and pesticides.)
I don’t mean to imply that avoiding dairy is an easy choice. It requires wrestling with the pain that a declining dairy industry would cause. I’ve met loads of farmers in my career as a journalist (and before that as a researcher), and it’s clear to me that they love their animals. Many of them are also working to reduce their emissions. Farming families also obviously make their living from consumer demand for dairy products (just as other farmers make their living from growing plants). The growing popularity of oat milk is a threat, and one that a powerful dairy lobby is trying hard to eliminate.
I don’t live under the delusion that by not drinking dairy I live a cruelty-free life. No such life exists. The coffee I put my milk in likely comes from land that’s been cleared of forests (once home to a more abundant array of wildlife). The cafes I go to use plastic lids. My clothes come from oil (nylon) and industrial fields of cotton. It’s a nightmare!
Nonetheless, I’ll probably continue opting for plant-based drinks. Drinking oat milk is not obviously bad or good, but relative to other ways I can help out, it’s easy. I’m increasingly aware — I almost wish I wasn’t — that choosing to buy dairy is choosing to cause harm to farm animals, wildlife, and our planet.