There are apps, but they are incredibly inaccurate. For starters, they don't recognize the food right. Usually you have to pick from a menu of 10 items. Then they have to estimate a 3D quantity (volume) from a 2D image, then they have to estimate the density... the amazing thing though is despite all this, they are still more accurate than recall diaries.
alt Hacker News
There are apps, but they are incredibly inaccurate. For starters, they don't recognize the food right. Usually you have to pick from a menu of 10 items. Then they have to estimate a 3D quantity (volume) from a 2D image, then they have to estimate the density... the amazing thing though is despite all this, they are still more accurate than recall diaries.