Meh. This quantified self business is just the next iteration of herbal remedies, Chinese medicine, and all that other pseudo-scientific mumbo-jumbo out there. You might as well add your astrological sign to all these apps.
Why would you think that? If anything, the self quantified movement is all about thinking scientifically to improve yourself. Gathering data, analyzing, designing experiments, generating hypothesis, and publishing for feedback are all part of being self quantified.
You make the assumption that people will use the scientific method with this stuff. The more likely scenario is that people will optimize for a single number (VDL/HDL, weight, or other) and miss the whole point.
The attitude that we can simply "optimize our life" is reductionist, arrogant, foolhardy. You will spend more time optimizing your numbers than you will living your life. But hey, at least you have the data to back it up :-)
Why would you think that? If anything, the self quantified movement is all about thinking scientifically to improve yourself. Gathering data, analyzing, designing experiments, generating hypothesis, and publishing for feedback are all part of being self quantified.