Starbucks' New Protein Lattes Are Sparking An Oleato-Style Controversy All Over Again

There is buzz on social media over the new Starbucks protein lattes introduced at the end of September, but not the good kind. Users on Reddit have been claiming that some decidedly unpleasant consequences followed after trying the protein drinks. The whole ordeal is beginning to sound like the Oleato controversy from 2023, in which some customers allegedly experienced similar digestive upset from Starbucks' olive-oil-infused beverages.

One of the first comments on Reddit appeared within a week of the lattes being released. A self-identified Starbucks employee posted about difficulties preparing the lattes, and replied to a comment suggesting the drinks caused gas by saying, "can confirm everyone in my store that tried it got a stomach ache." Another comment in the same thread got more colorfully explicit about the severity of stomach issues experienced after allegedly drinking a Starbucks protein latte. 

Just one day later, another Reddit thread detailed a customer's alleged experience with severe digestive distress after ordering the protein latte. "If you have digestive issues like me, or are maybe even missing a gallbladder, do yourself a favor and stick to your regular latte. This one is not for you," the poster concluded. That's not to say all feedback to Starbucks' protein lattes is negative; our own review of Starbucks' new protein lattes was overwhelmingly positive, and this Reddit post complimented the drinks profusely ... but at least one reply to that post also asserted that digestive discomfort resulted from the beverage.

The new Starbucks protein lattes are made with protein-boosted milk. That boost comes from whey protein powder, a common dietary supplement. If you ever check the protein supplements aisle of the store, you've probably seen whey protein sold in massive drums. Whey is made from cow's milk when it is heated. The curds are separated from the whey and used to make cheese products. The liquid whey is dried, and the powder is often used by athletes and bodybuilders on high-protein diets.

Starbucks uses whey protein isolate, which is refined to have more protein, and less fat and lactose than normal whey protein. If someone were sensitive it could cause digestive upset. Right now, there is no definitive explanation for the issues some Starbucks customers are allegedly experiencing.

In 2024, Starbucks discontinued its controversial Oleato drink line reportedly as part of a menu simplification. However, the drinks' run had been marred by significant negative criticism, including people making claims similar to those alleged about the protein lattes, such as serious and unpleasant stomach issues.

In the case of Oleato, it was speculated that the combination of olive oil, a relaxant, and caffeine — a stimulant — caused havoc with some people's insides. This time, the cause may be different, but it is allegedly still causing some people discomfort.