The short answer
The best evidence we found says an app keeps people logging longer than paper, though not forever. Picture the first week of a new food log. You photograph breakfast and type in lunch, then skip dinner because you are tired. By the second week the app sits unopened on your phone.
An app beats paper, for a while
A 2013 trial gave 128 adults trying to lose weight one of three ways to log their diet for six months: a phone app, a website or a paper diary. The app users recorded food on 92 days on average while the paper users managed 29. Every group still logged less as the months passed.
The trial measured weight loss rather than gut health, yet it is the clearest test of food logging formats we found.
Health apps lose people fast
A 2020 study looked at eight health studies run through phone apps, with more than 100,000 participants between them. The median participant stayed between 2 and 26 days depending on the study. Across all eight the median was 5.5 days. These were general health research apps, so read those numbers as a warning rather than a measurement of food trackers.
Wrong numbers are the other problem
Some apps now promise to read a whole meal from a photo. A 2025 study in the journal Nutrients asked ChatGPT to estimate nutrients from meal photos. It named the foods well but misjudged medium and large portions, which left most of its nutrient estimates more than 10 percent off.
When an app hides how it reached a number, you cannot check it. A wrong rating can steer you away from a food you could eat or clear one that keeps bothering you.
What GI Studio does about both
GI Studio goes after the effort first. Snap a photo, say what you ate or type it. The goal is a logged meal in about 10 seconds with nothing to tag.
Then it makes its answers easy to check. GI Studio does not estimate calories at all. Every rating shows its reason instead.
The lunch beside this page is mine: chicken and rice with soy sauce, logged from a photo. The app flagged nothing and listed exactly what it checked. If a line is wrong you fix it on the same screen. The app will still get some answers wrong. The reasons on screen are how you catch them.
So do they work?
They work for as long as you keep logging and the answers hold up. Ask that of any food app you try, including this one. A month in, are you still logging? Can you see why it rated a food the way it did?