The jury is in. In fact, it has been in for a very long time. No one was born irrevocably predetermined to become fat or anything else. Sorry.
Thanks to the Enlightenment, humans could begin blaming all of their faults on the deterministic actions of matter in the universe. Thanks to Freud, humans could begin to blame their failures on being stuck in a developmental stage. And, much more recently, thanks to the Human Genome Project, we have all begun to update the Medieval "the devil made me do it" to "my genes made me do it." I mean, after all, taking responsibility sucks, right?
However, despite all of our hopes and dreams that we could blame everything on inherited genes, it just isn't so. First off, genetic expression changes throughout your life and is dependent on your every act, choice and environmental change. Second, various discoveries disproved that malarkey: http://dmm.biologists.org/content/6/1/236.abstract. After all, it is pretty preposterous, since no matter what your genetic makeup, people stranded on an island with almost no food don't grow fatter.
Hey, it sure would be great. Imagine if you couldn't help yourself from having piles of cash stacked in scattered safety deposit boxes. Being a bank robber is just in your genes, so you couldn't help but collect all this money. But, alas, we all have to take responsibility for our actions and their outcomes, no matter how much we just want to believe that our taboo is externally induced.
Humans haven't become any more sophisticated in their fundamental desire to absolve themselves of all accountability. Point to the gods or the Higgs Boson. Your argument is the same. Headlines read "evolutionary biology discovery explains prevalence of rape." Really? If only we could prove that the most heinous acts in the universe were incontrovertibly fixed to happen, we could feel a lot better about our own little sins. Nope. You should've zagged when you zigged; and you had total control to do so. And you know it.
Yeah, yeah. I know. "Influence." Yes, genes, family, peers, mental disorders, addiction, etc. exert INFLUENCE. But influence is only influence. Influence isn't even potential. And potential isn't even actualized reality. It is scary. It's scary to say "I caved to these influences." It's an admission of weakness. And we all know admitting to weakness of character is much more difficult than blaming a condition. But you have to start somewhere to begin the change. And why not start with the only thing you can control: your reaction. You can't control others. You can't control who your parents were. So, why are you starting your change (or lack thereof) with talk about totally uncontrollable variables? Instead, let's focus on the empowering. You've got 168 hours of influence this week. Now go pick what you'll fill it with and how you react to it.