Apps that read a photo of your meal can tell you how many calories you ate. They promise a quick way to track food without typing anything. New research, however, shows that these apps often give numbers that are far lower than the real values.
Researchers tested four popular photo‑based apps with meals that were measured precisely in a lab kitchen. Each meal’s ingredients were weighed to the nearest tenth of a gram, giving a solid reference point.
How the Apps Work
The apps use image‑recognition technology to spot foods in a picture. They then guess the portion size and match the foods to a nutrition database. The result is a calorie count and a breakdown of nutrients.
Big Gaps in Accuracy
When the four apps—MyFitnessPal, LoseIt!, CalAI, and Appediet—were fed photos of 102 meals, they missed the mark by a lot. On average, each app reported 250‑345 fewer calories per meal. Fat was also under‑counted by about 30 grams.
MyFitnessPal and LoseIt! did a bit better with high‑calorie meals than with low‑calorie ones. All four apps were more consistent with carbs than with fats or proteins.
Low‑Carb Meals Are Tricky
To see why some meals are harder to evaluate, the team added another 200 dishes, many of them low‑carb ketogenic meals. These meals are higher in fat, and the apps consistently under‑estimated that fat content.
What This Means for You
If you rely only on a photo app, the numbers you see may be too low, especially for fat. It’s a good idea to double‑check portions or use a traditional food‑log alongside the app.
Combining photo tools with manual entry can give a more realistic picture of what you eat, helping you stay on track with your health goals.