Something that all geeks/nerds/etc. need to be aware of is weight. I mean that excess fat on the body that makes one look, well, fat. Being lonely, unwanted, too <whatever> to care is not an excuse. The biggest problem in science fiction fandom, geekdom, etc., other than social ineptitude, is being obese or morbidly obese which leads to Type 2 Diabetes. I know this because I was diagnosed last year and it caused me to mildly panic. Fortunately I had helpful guidance in shedding weight (115 pounds so far) and being able to keep it off. I say shedding instead of losing because something that is lost can be found.
I found that the quickest way to shed weight is to stop eating "recreational sugar" products. This includes, but is not limited to: candy bars, ice cream, sugary soda (I drink diet soda so I'm not exactly cheating), cake, cookies (which I like to bake so now I have to find sugar free alternatives), and other sweet goodness. It's okay to eat apples, sweet corn, etc. because the sugar is a natural and not added, but in moderation. Everything is in moderation. I gave up eating small pizzas by my self, even though I *love* pizza.
Exercise also helps. Just don't over do it. Start slow and work you way up. Pick I time when you feel comfortable doing it. I walk two miles in the morning three times a week, and add in other walks when I can. I have a small dog that I take for a walk in the evening.
Back to Diabetes. This can be a killer. A friend did not have his diabetes diagnosed and continued to live an unhealthy lifestyle. He was supposed to go to a New Years party some years ago but never showed up. He just disappeared off the fannish radar. Since this was before Twitter and Facebook became ubiquitous parts of everyday life no one thought twice about his silence until it lasted too long. Several mutual friends went to his apartment to check on him and found an unpleasant surprise. He was a groomsman at my wedding; I was a pallbearer at his funeral. I don't like this kind of symmetry.
Please, please, please take care if you are over-weight.