It works for Javier Garcia, a 28 year old neuroscientist who was recently profiled in the New York Times for photographing every single thing he's eaten over the course of the past 5 years.
Apparently there's a whole lot of folks like Javier out there, so many that I'm starting to receive blind PR pitches from iPhone developers who are creating apps for photographing food diarizing.
One such app is called Thin-cam and basically the premise is that you're less likely to forget what you've eaten if you've photographed it.
The PR pitch came with their handy dandy 10 reasons why it's a good idea and why it's superior to more traditional forms of food diaries (ie. counting calories).
So let me explain succinctly why it's not.
Pretend that times are tough and that you're trying to keep a careful household budget and you've decided that instead of tracking the costs of your purchases you're just going to take pictures of them.
Sound like a good plan?
Javier started his practice after losing 80lbs as a means to try to help himself keep it off. In that sense I can see potential value in that he may well be able to ensure he's not straying from the choices that helping him lose the weight.
Ultimately though, using a photographic food diary may help someone who's not keeping track at all and it may also helpfully augment traditional food diarizing, but it certainly won't supplant actually tracking the currency of weight, calories, in helping you balance your caloric books.
Spend the few seconds to write the foods down as you eat them (and at home ensure you've included measurements) - probably won't take much more time than pulling out your camera, framing your shot and taking it and it'll give you much more information.