MyFitnessPal is an app and service that lets its users track their exercise and their diet. According to the app’s owner, Under Armour, 160 million people are doing just that, which makes for a lot of data. And what better way to figure out how diet relates to weight loss than to look at this data?

“We wanted to ask the question: What are successful users doing that the rest of us aren’t?” Under Armour’s Rebecca Silliman told Co.Exist. “What can we learn from people who have set and hit a weight goal?“

The report is titled How to Eat Like a Successful MyFitnessPal User, and it is just that. Because users track their weight loss and their diet, along with—in some cases—their exercise, the data source is rich. And while diet and weight may be self-reported, users are often more honest with an app than with another person. Some years ago, I used the service to track my calorie intake, and I recorded every morsel, down to the last teaspoon of olive oil. To get these numbers, Under Armor used a sample of 4.2 million users.

MyFitnessPal also links to Apple’s HealthKit, which automatically tracks your health and exercise, and, if you wear an Apple Watch, it even records things such as your heart rate.

The big surprise in MyFitnessPal’s data is that the most effective users don’t eat like you might expect.

“One of the big takeaways,” says Silliman, is that “although we thought we might see that people were eating fewer carbohydrates or less fat, we didn’t. We didn’t even see them eating significantly fewer calories.”

Instead, they ate a lot more fiber—29% more, to be exact. In terms of overall carbs, the successful users ate around the same as the rest of us, but they ate more cereals (17% more), possibly of a fibrous kind.