• Posted July 27, 2026

How Accurate Are Photo-Based Calorie Apps? 4 Are Put To The Test

Snap a photo, get a calorie count. 

It sounds simple — but a new study finds some popular AI-powered food tracking apps may underestimate calories and fat by roughly a third.

"Photo-based calorie tracking apps are very popular, especially for people trying to manage their health or lose weight," said Aaron Hengist, a postdoctoral visiting fellow at the National Institute of Diabetes and Digestive and Kidney Diseases, part of the National Institutes of Health (NIH). "However, the accuracy of many of these apps has not been thoroughly evaluated. Our study helps address this question by looking at whether these apps can reliably estimate calories."

The NIH researchers tested four popular calorie-tracking apps — MyFitnessPal, LoseIt!, CalAI and Appediet — using photos of more than 100 meals prepared in a tightly controlled metabolic kitchen.

Every ingredient was precisely weighed, allowing the apps' estimates to be compared with the meals' exact calories and nutrients.

The result: All four apps underestimated the calorie content of the meals by 250 to 345 calories, on average, and fat by about 30 grams

The apps did a better job estimating carbohydrates than fat or protein.

"People using a photo-based tracking app without adjusting the portions or entering the amounts of food should take the results with a grain of salt," Hengist said in a news release.

A follow-up analysis of more than 200 additional meals also suggests the apps are less accurate with low-carb ketogenic meals, likely because they consistently underestimate their higher fat content, according to the researchers.

They say combining AI photo analysis with more traditional food tracking methods could improve the apps' real-world accuracy.

The findings were presented Saturday in Washington, D.C., at a meeting of the American Society for Nutrition. Findings presented at medical meetings are considered preliminary until published in a peer-reviewed journal.

More information

The U.S. Department of Agriculture has more on food and nutrition apps.

SOURCE: HealthDay TV, July 27, 2026