The tides seem to be turning against oat milk. Once the pinnacle of plant-based wellness culture, TikTok influencers are now turning away in their droves from the milk alternative, either back to cow's milk or towards other plant-based options such as almond or soya.
TikTok creators have accused oat milk of being too high in starch, containing inflammatory seed oils, and even causing acne in women.
So, Newsweek approached two nutritionists to get their opinion on whether this criticism is justified.
"Plant milks are extremely useful for people who are unable to, or choose not to, consume dairy products," said Melissa Smith, a nutritionist at the Alliance for Natural Health.
"We need to remember that plant milks are highly processed, often containing a range of ingredients you wouldn't find in dairy products such as seed oils and emulsifiers. Plus, they're often fortified using synthetic vitamins, which can mean you may end up having too much of a nutrient."
An emulsifier is a substance that helps blend two or more liquids that typically don't mix, like oil and water.
Smith added that non-organic oat milks were also likely to be grown "using intensive agricultural systems, exposing them to multiple agricultural chemicals," which could harm the environment -- and, as many content creators on TikTok pointed out, could affect health too.
Nutritional therapist Katie Sheen, from Soul Nutrition, said that while plant milks were helpful for people with an allergy or intolerance to dairy, they were "lower in protein, fats and a range of micronutrients" so might not be a healthy switch.
Sheen said she was aware of the criticism circulating about oat milk, saying: "The main thing that is being discussed on social media is the effects of oat milk on blood glucose levels, due to its comparatively low levels of protein and fat."
When we eat food, carbohydrates and sugars are turned into glucose in the body, and the hormone insulin is released to deal with that glucose, so it can be used as energy.
Foods that are higher in starches and sugars cause a bigger glucose spike, needing more insulin as a result, and this can lead to energy fluctuations and raise the risk of lifestyle diseases such as obesity and type 2 diabetes -- but foods containing fat, protein and fiber can slow this process down so it has a gentler effect on the body.
Oat milk, compared to cow's milk and nut milks such as almond "tend to have relatively higher levels of protein and fats than oat milk, hence a slightly lower impact on blood glucose levels," said Sheen.
However, she said that this didn't mean that almond milk was a better choice.
"There have been some dreadful environmental impacts of non-organic almond milk recorded that can't be ignored," said Sheen. "As will all foods, it is a very complex picture to unravel as to what is the 'best' choice to make."
She added that having oat milk as part of a meal or drink that contained fat and protein had a much different effect on blood sugar compared to having oat milk as part of a sugary latte, for example.
As for Smith, she said that oat milk could have a negative effect on blood sugars, but its importance depended on the quality of the rest of someone's diet.
"In a healthy person who's consuming low quantities of oat milk and following a largely wholefood, minimally processed, lower carb diet, I would say it's not a major issue," she said.
"If someone is using high quantities of oat milk as well as consuming a lot of highly and ultra-processed foods, particularly carbohydrate-based foods, then it could contribute to metabolic dysregulation and the development of health issues."
The other main criticism leveled at oat milk is that it can be a source of seed oils. Not all brands of oat milk contain seed oils such as rapeseed or canola oil, but some do.
"Many plant milks -- including oat milk -- contain seed oils, which tend to contribute to inflammation in the body," said Smith. "Modern diets lean towards higher levels of omega-6 oils, generally from highly processed seeds, which creates an imbalance in the ratio between omega-3 and omega-6 fats.
"Ideally, the ratio should be between 1:1 to 1:4, however the ratio in Western diets can be many times higher, due to the amount of vegetable oil consumed -- largely as a result of highly and ultra-processed foods."
Sheen agreed with all of this, adding: "Omega-6 is likely to be converted in the body to pro-inflammatory compounds, whereas omega-3 supports the production of anti-inflammatory compounds -- and inflammation is linked to a wide range of health conditions."
However, she added that cow's milk could have a different ratio of omega-3 and omega-6 depending on how the cow was raised, with milk from grass-fed cows tending to have a healthier fatty acid profile compared to milk from grain-fed cows.
Overall, Smith said: "Enjoy [your oat milk] in moderation, but be aware of the ingredients in your chosen oat milk and how it's been produced."
Meanwhile, Sheen said: "It may be more appropriate to focus on the food or drink that is combined with the milk of any kind.
"If you are consuming large amounts of tea or coffee, then I would suggest that the effects of caffeine on your health need to be considered as well as the glucose hit of the possibly small amount of plant milk that you are adding.
"And if the milk is on a highly processed or raw grain breakfast cereal then perhaps the answer is to move to a different choice of food where the milk isn't required anyway!"