We could measure the change in several objective metrics, such as:

• Annual income (higher is better)
• Time spent at work to achieve the same or greater level of income (lower is better, though of course this does not apply if one's work is also one's hobby)
• Weight to Height ratio (closer to doctor-recommended values is better)
• Number of non-preventative doctor visits per year (lower is better)
• Number of scientific articles accepted for publication in major peer-reviewed journals (higher is better)
• Number of satisfactory romantic relationships (higher is arguably better, unless one is not interested in romance at all)
• Hours spent browsing the Web per week, excluding time spent on research, reading documentation, etc. (lower is better)

The list is not exhaustive, obviously.