Well, this is amusing. But, after looking at some numbers on food production, it may simply be that CO2 is helping us grow more food. And what happens when a well fed population has more food? It eats it of course. The caveat is that correlation is not always causation, the Green Revolution (the agricultural one, not the crazy one) and Norman Borlaug had a lot to do with this too.
From ScienceNordic: New theory: CO2 makes you fat
Danish researchers have announced a rather wild hypothesis: Perhaps we are getting fatter and fatter because of the increasing CO2 levels in the atmosphere.
I had to laugh at this “fact” sidebar in the article:
Researchers are wondering whether CO2 affects embryos in the womb, so the embryos develop a tendency towards obesity.
This is one of the hypotheses that will be tested if the researchers can raise funding for large-scale trials with rats.
Gosh, giant CO2 fattened people and fat rats. These might do well with the smaller climate optmized green cat-like overlords from our other crazy story this week.
Other excerpts (tinfoil hats optional):
CO2 makes us eat more
This discovery made it possible to develop a precise hypothesis for how CO2 makes us fatter: We breathe more CO2, which makes our blood more acidic; this affects our brain, so we want to eat more.
In 2011, together with researchers Anders Mikael Sjödin and Arne Astrup from the University of Copenhagen, Hersoug started to test the hypothesis on humans.
At the university’s Department of Human Nutrition, they placed six young men in special climate rooms, where some of them were exposed to increased amounts of CO2. After seven hours, the men were allowed to eat as much as they liked.
This little pilot study showed that the men with the greater amount of CO2 in their blood ate six percent more food than the men who had been in climate rooms with a normal amount of CO2.
“We could also see that the extra amount of CO2 caused the men’s heartbeat to rise, and this gives us an indication that CO2 affects the brain’s nerve cells – orexins in the hypothalamus – which among other functions control our appetite and the composition of our nutrient intake,” says Hersoug.
“A very small change in the activity of these nerve cells will presumably have great importance for our development of obesity or for maintaining our weight.”
Does CO2 give men beer guts?
If the researchers’ hypothesis is correct, it raises many questions.
CO2 is found in the bubbles in fizzy drinks and beer – does that have any importance for obesity?
“Of course I have considered whether CO2 has very local impacts, which could explain how beer guts develop,” says the researcher.
Exercise and vegetables can limit the ‘CO2 effect’
But Hersoug says the hypothesis gives us no excuse for dropping diets and exercise – on the contrary.
“We know already that a sedentary lifestyle is a risk factor for many diseases,” he says. “According to our theory, this may be because of the higher acidity in the blood arising from a sedentary lifestyle indoors in a CO2 concentration that is higher than it is outdoors.”
On the other hand, he says, “If you’re out running, you get your blood circulating and you can pump much of the CO2 out of your body, so our hypothesis is really further evidence that exercise is healthy. And exercise may be even more necessary in the future, when we can expect even higher CO2 concentrations in the atmosphere.”
Hersoug adds that fruit and vegetables also reduce the blood’s pH value, so the CO2 theory is also an argument for eating more healthily.
Oh noes! Blood acidification – the next CO2 scourge! Breath deeply, it worked in The Andromeda Strain. Do not panic.
Read the whole thing here while you munch on a bag of buttered popcorn.