Guns, Germs and Steel argues, among other things, that differences in local geography had significant impacts on how various civilizations advanced throughout history. The biggest example cited is that the many small kingdoms in Europe and the following warfare gave advantages to counties that could develop technological advances while punishing those countries that tried to suppress them. Meanwhile, huge monolithic areas like China had no life-threatening incentive to push technology forward.
On a more personal basis, people who are dieting are often told to control their environment by not bringing unhealthy foods into their house. This is part of why I never buy junk food except for parties. No, cheese does not count as a junk food.
Now for a weirder effect. Recently my team moved into a new building at
at work. In our old building my desk was very close to the bathrooms, and I walked by them pretty much any time I had to go anywhere. In addition, the bathrooms got crowded, especially after lunch. Because of this I used the bathroom more or less whenever I needed to.
So now we're in a new building. My desk isn't particularly close to the bathroom, and for the most part I have to go out of my way to walk past the bathroom. Perhaps not surprisingly, I've found that I rarely use the bathroom more than once or twice a day, even though my diet is largely the same as before, aside from (so far) attempting to eat
far less sugar.
In other words, I've got the same food inputs. My health hasn't changed noticeably. The only significant difference is a reduction in my proximity to the bathroom, and I use the bathroom less. The human body is weird. Control your environment, and you control yourself to some extent.