You could spontaneously combust. There's food for thought.
3. Weaken Immune System
Remember your good ol' immune system? How it would take care of you day and night, ensuring that parasites, viruses, bacteria, and fungi don't simply march into your body and start decomposing you while you're still alive? Well, regardless of how many vitamins and exercises you eat or do, (Surely, you don't exercise vitamins) your body can still become susceptible to disease by simple things you fail to do daily. Ranging from basic hygiene to your mind-set, your conscious and unconscious mind can play a big role in the physiology of your working, functioning body.
One sure-fire way to weaken your immune system is to deprive your body of sleep. Instead of allowing your body to re-build it's natural defenses and fight the evils of the world another day, you can sit around on your computer all day and slowly destroy your immune system. The result is as obvious as for any weaken immune system; you'll find yourself contracting diseases more often and that the diseases last much longer in your body due to your body's inability to fight the disease quickly and effectively. Sounds like fun, sign me up.
Congratulations, you are now a proud owner of a weaken immune system.