Let’s be honest: coffee is basically a universal love language – and we're especially passionate about it here in the UK. Most of us reach for it first thing (one analysis found 87% of coffee drinkers have it in the morning), and plenty keep going well past lunchtime – with some even ordering lattes, cappuccinos and flat whites in the evening, too (the Italians would be fuming).
And while a splash of cow’s milk used to be the default, the “what milk?” question has become the new normal. Plant-based options are now firmly in the mainstream, with oat milk emerging as the go-to for everything from home brews to barista-made flat whites—thanks to its creamy texture and crowd-pleasing taste.
But oat milk’s glow-up hasn’t been totally drama-free. In recent years, it’s been criticised from multiple angles: some nutrition experts have flagged its potential to spike blood sugar for certain people, others point to added sugars in some versions, and it’s also faced scrutiny over environmental claims, depending on how impact is measured.
So, is oat milk still the smart swap it’s been sold as... or is it time to rethink what we’re pouring into our coffee (and over our cereal)? Cosmopolitan UK spoke to nutritionists to get the facts, minus the hype.
What is oat milk made out of?
"Oat milk is typically made using a syrup made from oats, which is then combined with water. Many of the most popular oat milks on the market also contain oils, emulsifiers and stabilisers too," registered nutritionist Jenna Hope explains.
In fact, it's possible to make your own oat milk at home, agrees Caroline Hind, Registered Nutritional Therapist at Nutrable, by soaking oats in water and sieving the liquid.
"In reality, many oat milk products contain additives such as artificial sweeteners, vegetable oils and preservatives," she tells Cosmopolitan UK. "It's worth reading your labels to find a product that's mostly oats and water."
Is oat milk good for you?
When you drink oat milk, you're effectively knocking back starchy water, which can be carbohydrate-heavy, say the experts. Comparatively, there can be between 15 and 20g of carbs per glass of oat milk compared to around 8g of carbs in a glass of cow's milk. It also has 2.5g of protein per glass, about 4g of unsaturated fat, and around 2g of fibre. Cow's milk, on the other hand, is much richer in protein, containing between 8 and 10g per glass.
Hind says: "The concern about sugar in oat milk is not so much about added sugar as about the glucose content of oats themselves. The high starch content in oats breaks down into glucose in the gut, passing into the bloodstream as glucose and raising blood sugar."
The expert also says that many oat milks contain additives that can trigger inflammation and disturb metabolism, the gut microbiome and other aspects of health.
Should we replace cow's milk with oat milk?
On the whole, both nutritionists agree that cow's milk is the more nutritious option.
"Dairy milk consumption is associated with better metabolic and cardiovascular health," Hind explains. Hope argues that cow's milk is much higher in micronutrients such as phosphorus (something that helps with the formation of bones and teeth), calcium, vitamin D, B vitamins and potassium than oat milk.
However, cow's milk isn't always an option for everyone – be it due to an allergy, personal taste preference or following a vegan diet – and if you're firmly team oat, don't stress. It's not all doom and gloom; the experts just advise you not to overdo it. Like any food item, everything is OK in moderation.
Ultimately, Hope says that oat milk's main advantage is taste. And, that it's a "reasonable alternative if used in small amounts, for example, in coffee."
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Who should avoid drinking oat milk?
According to Hope, those who are diabetic would be better off with a higher protein, lower sugar alternative such as soya milk. This is due to oat milk's high sugar content.
Additionally, she adds that oat milk can "contain more calories than other milk alternatives, therefore those who are looking to watch their weight may choose a lower calorie alternative."
(Disclaimer: You should only look to lose weight if it's the right health journey for you. Every person is different, and there is no right or wrong body shape. In fact, it's what makes us unique!)
Are there any side effects of oat milk?
Hope assures that "drinking oat milk in moderation is safe," but warns that, like any product, "you don't want to over-consume it." This is because of the higher amounts of sugar, as mentioned earlier, plus the presence of refined oils.
How often should you drink oat milk?
On the whole, it's pretty safe to regularly consume oat milk. But Hope advises making an effort to regularly mix up your milk alternatives wherever possible.
She adds: "If you enjoy oat milk for the flavour you're better off having it in a coffee or matcha. Then, use other milks such as unsweetened almond or soya for smoothies, porridge and in baking where the taste is less relevant."
Is almond milk better than oat milk?
Of course, oat milk is not the only alternative milk product out there. Almond milk is becoming increasingly popular, too.
"Unsweetened almond milk is lower in sugar and higher in protein than oat milk," Hope explains, for those worried about health impacts.
However, as Hind warns: "Not only are many people sensitive to nuts in the diet, but almond milk can be high in oxalates, which can trigger issues such as kidney stones."
If you are looking to pick a milk alternative, Hind suggests lactose-free cow's milk, or coconut milk. Elsewhere, Hope suggests soy milk, as it's the most similar to cow's milk in terms of nutritional value: both contain similar amounts of calcium and vitamin B12, but a glass of soya milk provides more riboflavin (a B vitamin that helps the body to convert food into energy) and vitamin D.
No matter what milk alternative you choose, it's important that you seek a carton that is free from artificial sweeteners, vegetable oils, preservatives and starchy fillers if you're looking to make a health-conscious choice.
This article is not intended to be a substitute for professional medical advice or diagnosis. Always seek the advice of your GP or other qualified health provider with any questions you may have regarding a medical condition and before taking a new medication or supplement.
Kimberley Bond is a Multiplatform Writer for Harper’s Bazaar, focusing on the arts, culture, careers and lifestyle. She previously worked as a Features Writer for Cosmopolitan UK, and has bylines at The Telegraph, The Independent and British Vogue among countless others.
Sophie Williams is a Freelance Journalist and Copywriter, covering everything from Fashion to Entertainment to music, Lifestyle and Features. She has interviewed a range of musical artists and authors including Alyssa Edwards, Courtney Barnett, Confidence Man, The Vaccines, Loyle Carner, Gabrielle, and John Niven, and has written for publications like Metro, Reader's Digest, ITV's Woo! and Vice’s NBGA. She is also working on a book for HarperCollins about Taylor Swift, due to be published in 2024.
