It may look like you don't. It may look like, even if you do, it's too complex for your decision making to play a role. But your decision making does play a significant role.
Science confirms it: http://citeseerx.ist.psu.edu/viewdoc/download?doi=10.1.1.690.8118&rep=rep1&type=pdf
Read more here:
For years I've heard people try to quantify what percent of fitness success can be attributed to either "working out" or "nutrition." Is it 50/50? Is it 80/20? Is it 90/10? My answer: wrong question. Mindset is Everything. And your mind goes where it will. Your identity, actions, words and even genetics will follow. The sets of instructions in your body are only as powerful as which ones are turned on and activated. Think of DNA like a field of nuclear weapon silos. Their presence only represents potential. Unless you choose to fire them, you aren't in a state of overt nuclear war: https://www.whatisepigenetics.com/what-is-epigenetics/
I've written about this before.
Here - Genes Don't Make You Fat
And here - Genes Don't Make You Who You Are
And how to change anything.
The reason I even bring up this topic again is because it sits smack dab in the middle of all internal debates over change. People want to change. Or they think they do anyway. And I see the struggle every single day, including this very hour I write this post:
Today I had appointments from 5am to 3pm with no breaks. When I was wrapping up my first appointment of the morning, I noticed my 6am was not here (and it was nearly 10 minutes after). I checked my phone to find that she and her husband (my 8am client) both cancelled because of the "dangerous" cold. "Odd," I thought, since it was warmer today than when they were here on Monday. I was outside both days at the same time, and it was at least 5 degrees colder Monday. I looked up the weather and found that there had been predicted some wind gusts which could create wind chill; but I just stood outside (in between writing these two sentences) without a jacket with my sleeves rolled up for 10 minutes and it's dead, no wind, not unbearable (and later that day I and my son, who was 3 at the time, were wholly unaffected playing outside for a while). Windchill does not matter if you're covered up anyway.
Since I was reading the text aloud, my 5am client as she was packing up to leave rhetorically queried/opined, "are they young children who have to sit at a bus stop for 45 minutes waiting for a bus that may not arrive because it's broken down while their parents have had to go off to work already?" I laughed. But then... I just felt sad. I love them like family. They are awesome people. Out of all the clients I have today, they are the only ones not showing up. They are not the oldest. They have the most reliable transportation of all. They live closer than any other appointments. Their cars are in a garage.
I know. Sometimes people have other things going on, and they feel it's polite to blame circumstances. But I fear it's deeper. And not to offend anyone, but you can either think like a lean person or you can think like a fat person. Tony Robbins (yes, I like Tony; don't judge me) calls this "modeling." If you want to be a certain way, you have to think like THAT person.
Yes, this can start to get complicated with phobias and addictions. In this case, sometimes action will have to precede belief. If you act like someone who doesn't have a phobia or addiction long enough, you become it. You think it. Then you become it. Then you do it naturally.
That is, once you choose a course of action or a goal, you must commit wholeheartedly, which in turn will change the genetic imprinting. If you say that you want to lose 80lbs, every decision must be couched in the question, "what do people who actually lose 80lbs do?" Do they punk out of a workout because it's too hot? Do they back down from a session because it's too cold? Do they eat crap in the face of stress, holidays, peer pressure? No. They choose to change their DNA.