If you’ve ever tried out a dieting app, you might have filled out a questionnaire asking you about your body type, weight, exercise, and eating habits, and possibly even medical information, like whether you have diabetes. Ostensibly that data is used to inform what kind of diet the app suggests, but new research reveals diet companies may be using it in other ways. According to London-based non-profit Privacy International, diet apps are sometimes sharing this data with third-party marketers and not protecting it securely. The report also raises questions around whether U.S. laws adequately protect online health data that isn’t hosted by a medical entity.

Researchers at the organization filled out questionnaires for the diet apps Noom, BetterMe, and VShred several times, each time entering slightly different data to see if it rendered a different recommendation. The researchers found that regardless of the data entered, the results tended to be the same. For example, the researchers entered a variety of starting weights and goal weights into BetterMe. Each time, the suggested plan was identical, promising that the person could lose nine pounds after the first week of the program and that 83% of “similar people” lost more than 17 pounds on their platform. (In a response, BetterMe says that the data is used to determined a daily calorie intake and whether individuals have dietary preferences, like vegetarian).

The same was true for VShred, which asked for gender, age, height, weight, exercise habits, and workout goals. While the company did provide people with a custom set of “daily macros” or allowed calories, carbohydrates, fats, and protein per day, its fitness and nutrition recommendations were the same books and mobile videos regardless of the information entered. Noom, by contrast, gives clients a timeline within which they will lose weight and then asks for additional personal information as a way of predicting the shortest amount of time to meet a weight goal. In total, Privacy International estimates that Noom asks at least 50 questions about a person’s mental health, physical health habits, and medical profile.

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