Genetics loads the gun, our choices pull the trigger. Gaining massive amounts of central body obesity and having an appetite that could rival my huge, active brothers? Not a choice. Hunger dictated my eating. I didn't have much on an off switch. Was active and ate mostly healthy choices, certainly better than the majority of my peers. And I managed to get up to a morbidly obese BMI as a teen.
I didn't ask to come from a line of diabetic, cancer prone, stoutly proportioned folks. It happens. To 'fix' that, I have to account for it. I have a predisposition toward obesity and have pounds of emaciated fat tissue trying, at all times, to refill themselves and be in homeostasis again. I didn't just fill fat cells, my body grew NEW ones. And all those cells exert a strong hormonal influence on my body and drive the hunger/satiety feedback loop I live in. Genetics determined quite a bit of how my body responds to nutritional stimuli, and that's not in my head.
Now. That doesn't mean there isn't a choice. There IS. This is the body I have to work with, so I have had to tweak, experiment, and work my way down the scale, in the midst of living in an imperfect world with this body I've been given. That means I must be smart - I am very hormonally sensitive, and I can't eat like I'm not. I can't lose weight without ravenous hunger beyond a certainly point because of all that empty fat tissue sending signals to my brain that they are starving. Okay - so I have to manage my hunger without causing them to store energy, and give my body a satiation cue without taking in enough energy to rebound to my initial size. For me, this means low carb and whole foods, together.
I'm also blessed with a strong immune system. Too strong, actually, as it ruthlessly attacks the tissues of my body when certain inflammatory factors are present. So my diet must also manage that inflammation, or I feel like crap and can barely move for the fatigue, all cravings and sleep disturbances aside.
Then there's the reality that I'm pregnant or nursing frequently and have been for the entirety of my weight loss. So I must manage nutritional (micronutrients/vitamins/sufficient protein/fat) for physiologically demanding processes while not bouncing back up the scale. That's a trick, too, and takes lots of attention to detail and tweaking.
There are plenty of choices I have made that can and do equal my long term weight and health management. But it is asinine to ignore that different bodies have different requirements and challenges, and that the sweet spot for one person is going to be entirely different than for another. My body doesn't demand energy or respond to the input like a woman with ten vanity pounds to lose. I'm not built like that, my metabolism doesn't function as sensitively, and the hormonal cocktail my body manages is different than someone who isn't metabolically resistant and has never had profound pediatric obesity.
I also can't eat like someone whose blood sugar is more tightly controlled and doesn't dump massive amounts of insulin at a lick of a prune or banana. I can't eat like someone who doesn't get sick from proteins in most grains, or metabolizes yeast well, or doesn't get patches of skin falling off with too much sugary dairy. It just isn't happening. Those things are NOT a choice.
But what I do with them? That is. My physical vessel was given to me. My response to that is where the difference lies. And a culmination of hundreds of little choices every day is why I am not as wide as I am tall and on the expressway to a sick life and possible early death.
But a key distinction to make - the choices that might make one person's body smaller or healthier might NOT make mine smaller or healthier. Calories matter, but it is only a part of the equation. There is so much variation and that absolutely must be accounted for. Feeling starving at 195 and unable to stick with my diet vs perfectly satiated at 163 wasn't some massive feat of my willpower. Nothing about me essentially changed. The difference was the diet, the method I used to manage my symptoms. One method, that worked perfectly well for dozens of folks, was leaving me starving, cold, and miserable. Another, which regularly gets lambasted by folks who do NOT have the same kind of body I do, has been dietary salvation for me. Suddenly I DO have that off button I never had as a kid. I CAN consume normal portions of food and feel satisfied, rather than starving for more just two hours later. I can wake up refreshed instead of more tired than I was the night before.
Choices are part of it, but the right choice isn't always so simple as just eating less. And genuine, physiological hunger can still be felt even when one has hundreds of pounds of stored bodyfat they should utilize first. Distilling it down to either genetics or choice ignores that our bodies are dynamic, unique environments unto themselves, and every bit of stimuli (food) we put in them has a real and measurable effect throughout our body's systems. It isn't a math equation or moral failing that makes many people obese, any more than it is hyperventilating that makes someone asthmatic. Obesity is a symptom of how our body manages or mismanages nutrition far more than the cause of it, especially in most people with early onset and morbid obesity to contend with.