Life is definitely complex, but most of the variables with some influence on weight are either unobservable or unchangeable.
Luckily, you don't need to observe them or change them. You can ignore them and focus on what is observable -- appearance and weight -- and on what is controllable -- diet and exercise.
It may well be that gut biomes, antibiotic usage, inflammation, corn syrup, global warming, diesel particulates, preservatives etc etc have an influence. But the forcing factor in the weight system is net caloric balance, which is also the easiest to control.
> But the forcing factor in the weight system is net caloric balance, which is also the easiest to control.
Are you kidding? Almost nobody who diets to lose weight manages to keep it off for 3 years. In the very short term (say, up to 6 months) people can control their weight via diet/exercise changes, but in the long term they generally can't. If we figured out what was going on and it turned out to be any of those other sorts of factors it would almost certainly be MUCH EASIER to control weight using those other factors than via diet and exercise.
That may be, and on an individual level it makes sense to focus on diet and exercise.
From a science and a policy point of view it makes a lot of sense to investigate what might be causing N% of the population to balloon in weight if they maintain their default diets and levels of activity.
//edited to add
Reason being that it might be possible to give someone a pill or a treatment that allows them to consume tons of calories and be sedentary without the health drawbacks related to obesity. From a policy point of view that would be a big win.
The default diet has increased and default levels of activity have fallen.
Put another way: the environment has changed. People have not.
For any given gradient across the population of desire to eat tasty food and desire to not engage in physical activity, the environment is progressively affecting more and more of the population.
I'm not sure you're responding to my post. I agree with regards to activity levels and caloric intake—but I'm saying it is worth investigating further.
It reminds me a lot of the lead hypothesis in regards to crime. The simple model would state that more people in prison and harsher law enforcement causes crime to decrease. However, if the lead hypothesis is true, then we can stop wasting resources on crowded prisons and draconian law enforcement, instead focusing on getting lead out of the environment. Or, more realistically, do something in between those extremes and at a policy level be far more successful.
> I agree with regards to activity levels and caloric intake—but I'm saying it is worth investigating further.
Absolutely. Science is worthy for its own sake, it doesn't need an extrinsic policy motivation.
As for falling crime, my understanding is that the criminologists are still arguing about that one. Especially since it seems to be a global phenomenon.
Check out the Mother Jones article by Kevin Drum. It's got quite a lot of references. The lead hypothesis is fascinating. The change in crime tracks lead levels internationally as well. While it is probably not the _only_ cause of the late 20th century crime wave, it's likely one of them, and might be a major one.
I have to wonder if there's a strong link to poverty or economic stagnation as well. With income disparity reportedly increasing by leaps and bounds, it's possible the crime of the last century and the recent violent uprisings in the US were all influenced by the economy.
It's intuitive, but I'm not sure if there's a causal link. The 20th century saw an incredible increase in income equality and that was the highest point in the recent crime wave. In fact, the increase in income inequality in the US over the last thirty years has coincided with the drastic decrease in violent crime, which is super interesting because it implies that those variables might be more independent than originally thought.
Luckily, you don't need to observe them or change them. You can ignore them and focus on what is observable -- appearance and weight -- and on what is controllable -- diet and exercise.
It may well be that gut biomes, antibiotic usage, inflammation, corn syrup, global warming, diesel particulates, preservatives etc etc have an influence. But the forcing factor in the weight system is net caloric balance, which is also the easiest to control.