I am working on an application that does something similar. The idea is to create a 3D avatar using 3 pictures (front, side, back) of a person. Like bodylabs, I also have a statistical model of a person (although not yet as detailed as their), so transforming the person should be doable.
It's a very good idea, you should work on it. Although the face model should be quite detailed or the user will see their "uncanny valley" self. I would use such an app. It has a high viral potential: people could share on social media fatter/thinner faces of themselves or famous people they like.
I made something like this while working at a payments provider for the fitness industry. It'd take a full-body shot of the person and a current weight and goal weight and then generate a new full-body photo showing what they'd look like. It turned out to be simple to make and it worked really well. Unfortunately, they don't have it mentioned in any of their marketing materials, so I can't link to it.
They had me make it so that the gym could use it as a selling tool, but I was too far removed from the gyms to know if it was effective, or even if it was widely used.
I found a product with similar end results. I'm not sure if their solution is also automated:
Totally, a great idea for fitness!
In our statistical model, we actually have a measurement called fitness. It is mapping hours of exercise to how muscular a body will be which is learned from really world data. We are planning to expose this measurement in the future!
1. Let people enter their measurements.
2. Ask people to upload a photo of their face. Slap it as texture onto the head.
3. Do an animation: This is you, if you lose X pounds of weight / gain Y pounds of muscle.
Let people save this and use for motivation.
There's something intriguing SEEING yourself transform in front of you. "This is how you could look like" and it's tangible.
Maybe I should make an app for that :D