Where did it all go so wrong for oat milk?

Where did it all go so wrong for oat milk?

Like many people, when 23-year-old Kate first switched from dairy to oat milk in 2019, her primary concern was the environment. “I was a big oat milk girlie, for environmental reasons for the most part, but also for health,” she tells me. “I wasn’t eating meat for the environment as well.”

At the time, veganism was experiencing an unprecedented surge in popularity. While soya milk had previously been the most popular plant-based alternative, unsubstantiated rumours of health concerns surrounding its oestrogen levels began to circulate.

This, combined with the environmental cost of almond milk using up vast quantities of water, created a power vacuum for oat milk to begin its meteoric rise. Closely mirroring the froth and creaminess of cow’s milk, oat milk quickly emerged as the dairy milk alternative of choice, with sales increasing by over 100 per cent between 2019 and 2020.

Oatly led the oat milk charge in the UK (Oatly)
Oatly led the oat milk charge in the UK (Oatly)

“We were all [my friends] drinking oat milk back then – our uni house fridge had about six cartons at a time,” Kate says.

Almost overnight, it was impossible to step into a coffee shop without hearing “oat latte?” Every cafe’s default plant-based milk was suddenly oat, having gone from being the proviso of ardent vegans to a genuinely mainstream option. Driven in large part by the success of Oatly, a Swedish company that invented oat milk in the early 1990s, the fervour for oat milk reached such fever-pitch in 2021 that the brand actually faced shortages.

However, over the last year a flurry of reports and viral social media posts have cast a shadow over oat milk’s ascent to supremacy. Once the milk that could do no wrong, it has now variously been slammed by nutritionists as causing blood glucose spikes, bloating, skin issues, being protein-deficient and bearing the nutritional equivalence to a glass of sugary water.

A now viral TikTok video by actor Andrea Valls titled “cow’s milk when she hears you’ve quit oat”, summed up the volte-face: “Well, well, well,” Valls says, donning a fur coat and fake cigarette. “Look who’s come crawling back… Had enough of her spiking your glucose, have you? I should have known what you were up to from the start, all them years ago. Stopped ordering me in your Costa; started ordering her instead.”

It appears that sales of oat milk are bearing out this cultural shift. While Oatly, the leading retailer, managed a 0.3 per cent growth in volume last year in the UK, this is miniscule compared to its 2019-20 sales.

“I realised it was more unhealthy for me than I initially [thought], particularly the fact it can be bad for your blood sugar and energy levels,” Kate tells me. “I’m lazy by nature, so I just thought when it came to getting other nutrients, dairy was ultimately the easiest way to get them.

“Oat milk is the only dairy alternative that I liked the taste of, so the others weren’t on the cards for me. Nowadays, I’d say only one of my friends has stuck with [oat milk], and she’s got a dairy allergy.”

After posting a callout on social media for interviewees for this piece, the responses were overwhelming. “I’ve started avoiding oat because of fear mongering about ultra-processed food and rapeseed oil or whatever,” one of my friends said. “But is dairy any better for you? Who knows.” One had recently switched after ten years. Another, a diehard vegan, had switched to a combination of other plant-based milks.

Search the hashtag oat milk on TikTok, and you’ll find scores of videos of nutritionists and dieticians giving their often not-so-favourable assessments of oat milk’s value. One clip which has garnered widespread attention is an interview with French biochemist and New York Times bestselling author Jessie Inchauspé, who gave the following damning summary: “Oat milk comes from oats, and oats are a grain, and grains are starch. When you’re [drinking] oat milk, you’re [drinking] starch juice. You’re [drinking] juice with a lot of glucose in it. So it leads to a big glucose spike.”

After coming across one of these videos, 24-year-old Ellie decided to quit oat milk for good. “I was a very firm oat milk girl for a solid five years,” she tells me. “And then I saw one podcast clip on Dr Rangan Chattergee’s page, and the woman on it was saying that it makes your skin worse because it’s comparatively got so much sugar in it.”

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But just how true are these claims about oat milk’s status as the bogeyman of beverages? There is an overwhelming amount of information out there, and when combined with a desire from users to go viral, it is difficult to decipher the truth from fear mongering.

“Since oat milk does contain naturally occurring sugars, it can cause rises in blood sugar,” says registered dietitian and nutritionist Dr Reema Pillai. “Because the oats [in oat milk] have been finely ground, this means the food matrix of the whole oats has been disrupted, meaning the natural sugars from the oats are easier to absorb. This could lead to a large spike in blood sugar compared to eating whole oats themselves.”

“But remember, having spikes in blood sugar after eating is completely normal, and not harmful,” Dr Reema continues. “The body will work to bring down the blood sugar in a timely manner. Ensuring that you pair the oat milk with a source of protein or fats, will help reduce the spike.

Another prevalent claim about oat milk is that it can cause bloating. This is why 30-year-old Charline decided to give up the milk, after drinking it for years.

“After learning more about oats and oat milk, I figured that’s what was causing my bloating, so I stopped drinking it,” she tells me.

However, Dr Reema has found little evidence to back up this much-touted claim. “Bloating is not a very common side effect associated with consumption of oat milk,” she says. “Although it does provide a source of fibre, this is relatively small, unless large quantities of oat milk are consumed. If someone is sensitive to the types of sugars found in oat milk, this may lead to some discomfort through bloating, however it again can depend on the quantity and what else is being consumed alongside the oat milk.”

What is undeniably true, is that cow’s milk contains more protein than its oat alternative.

“Dairy milk provides a source of protein, calcium, iodine and vitamins A, B12, D,” Dr Reema says. “The protein it contains provides all the essential amino acids, meaning that milk is a complete protein.

“Oat milk is a poor source of protein, and naturally is not a source of many of the nutrients that dairy milk contains, though many of the oat milks available in the market will be fortified.”

Alternative milks have taken over UK supermarkets (Getty Images)
Alternative milks have taken over UK supermarkets (Getty Images)

Whether or not this impacts your milk choice will largely depend on your other sources of protein. Oatly’s resident nutritionist, Ulrika Gunnerud PhD, contests the importance of milk’s protein level.

“Whilst oat drinks do typically have lower levels of protein than cow’s milk, for people eating a balanced, varied diet, which fulfils energy needs, insufficient protein intake is not usually an issue, as we are getting more protein than we need,” she says.

"The majority of plant-based drinks (including oat versions) are fortified with micronutrients typically found in cow’s milk, such as calcium. Take Oatly as an example – our drinks are fortified with calcium, iodine, riboflavin, and vitamins B12."

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There have also been concerns about the health impacts of additives and emulsifiers such as flavourings, thickeners, carrageenan, vegetable oils and gums that can be found in non-dairy drinks.

“If you consume oat milk in moderation in an overall balanced and nutritious diet, this is not an issue,” Dr Reema says. “However, if you are regularly consuming numerous foods that contain emulsifiers and additives in larger quantities, this may lead to a disruption of our gut microbiome, which has been linked to changes in our mood, metabolism and inflammation in the body.

“More research is needed to assess the full extent of these additives to our health, before specific guidance can be given – though if you do enjoy oat milk, aim to consume it in small quantities and pair it with whole foods rather than high levels of processed food products, to help create a healthier balance overall.”

It’s also important to note that, while dairy milk is less-processed than plant alternatives, it too can contain some rather unsavoury ingredients, such as antibiotics. And if environmental impact drives your consumption habits, no milk is more destructive than dairy milk – research shows that a glass of dairy milk produces almost three times the greenhouse gas emissions of any non-dairy alternative.

Certainly, the apparent decline in oat milk’s popularity does not necessarily signal a wholesale switch away from all plant-based milks, or away from veganism in general. “I’ve moved on to soya,” Ellie says. Her reasons for giving up dairy milk were ethical, and she spent a few years completely vegan.

“I would definitely not drink dairy. To me it actually tastes like cow smell, like cow sweat,” she continues. “I do eat cheese and chocolate, but cow’s milk is not for me, which is probably hypocritical.”

Charline agrees. “I’ll never go back to dairy milk,” she says. “Coconut or almond it is. [Oat milk] tastes so good though so I have it every now and then.”

Overall, the milk you should choose will depend largely on what you use milk for, and the strength of your ethical considerations. No milk is a silver bullet for health – all have varying pros and cons.

For those who view milk as a means to add creaminess to their coffee, oat milk’s nutritional profile probably matters less than its ability to make a frothy latte.

How different milks compare in nutrition and carbon footprint

Cow’s milk

Tesco Cow's milk (full-fat) nutrition per 100ml:

  • Sugar – 4.6g sugar

  • Protein – 3.4g

  • Fat – 3.6g

Environmental impact (global):

  • Carbon emissions (co2eq) – 3.2

  • Land use (m2) – 90

  • Water use (l) – 682

Oat milk

Oatly Original nutrition per 100ml:

  • Sugar – 4g

  • Protein – 1.0g

  • Fat – 1.5g

Environmental impact

  • Carbon emissions (co2eq) – 0.9

  • Land use (m2) – 0.8

  • Water use (l) – 48

Soya milk

Alpro Soya unsweetened nutrition per 100ml:

  • Sugar – 0g

  • Protein – 3.3g

  • Fat – 1.8g

Environmental impact

  • Carbon emissions (co2eq) – 0.9

  • Land use (m2) – 0.8

  • Water use (l) – 48

Almond milk

Alpro unsweetened nutrition per 100 ml:

  • Sugar – 0g

  • Protein – 0.4g

  • Fat – 1.1g

Environmental impact

  • Carbon emissions (co2eq) – 0.7

  • Land use (m2) – 0.5

  • Water use (l) – 371

Rice milk

Rice Dream nutrition per 100ml:

  • Sugar – 4g

  • Protein – 0.1g

  • Fat – 1.0g

Environmental impact

  • Carbon emissions (co2eq) – 1.2

  • Land use (m2) – 0.3

  • Water use (l) – 270

Source: Poore and Nemecek (2018), Science