The New Relationship Between Income and Obesity
We’ve noted it before. The relationship between income and obesity is tricky. And according to a new paper from Alexander Bentley and colleagues, the relationship is very new. As recently as 1990, they say, it simply wasn’t there. Today, it’s quite clear. Less income predicts more obesity. Likewise, the correlation between income and diabetes is strong today. But it was insignificant in 1990.
Social or Environmental Factors?
How has this relationship changed so quickly? Crunching through a lot of data, Bentley explores two competing explanations: social learning and human behavioral ecology (HBE).
On one hand, social learning emphasizes the ways that people adapt their behaviors by observing and learning from people around them. On the other hand, HBE puts the emphasis on people adapting to their environment. People adapt to changing conditions and those adaptations bring changes in physiology.
In the end, Bentley et al find more evidence to support HBE as a driver of the obesity epidemic. They conclude that greater exposure to inexpensive, highly caloric foods could be a key factor. In high-income countries, the poor have more access to cheap calories. Human physiology favors increased fat storage in response to scarcity. Poverty is all about scarcity. But even in poverty, many people have access to cheap calories now.
So fat storage takes off like a rocket.
Speculation with a Fresh Perspective
Bentley et al are pretty clear about one thing. Their conclusions about HBE and obesity add up to nothing more than well informed speculation. We need much more research and analysis to tell the full story. But this research brings fresh eyes to our efforts to understand obesity. It offers the perspective of anthropologists, backed by some rigorous math.
Fresh thinking is always welcome.
Click here for the paper and here for further reporting.
Golden Temple in Amritsar, photograph © Arian Zwegers / flickr
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December 15, 2018
December 15, 2018 at 9:30 am, Allen Browne said:
Yes, poverty is all about scarcity. But more than scarcity of food. Also scarcity of healthy sleep patterns and amount, scarcity of stress free moments, scarcity of exposure to obesogens – all modifiers of the energy regulatory system. But then what about the reverse relationship between income and obesity in less developed countries – India is an example. Obesity remains heterogeneous.
Allen
December 15, 2018 at 11:22 am, David Brown said:
We need more research? Not really. In a 2003 Orlando Sentinel article entitled ‘Hunger Confronts Bigger Issue’, global obesity expert Barry Popkin repeatedly mentioned the global increase in the use of vegetable oils for food preparation:
“If you go back to those same villages or slum areas today … their diet includes a lot of vegetable oil … In China … Rice and flour intake is down, and animal-source foods such as pork and poultry and fish are way up, and the steepest increase is in the use of edible vegetable oils for cooking …
“People are eating more diverse and tasty meals; in fact, edible oil is a most-important ingredient in enhancing the texture and taste of dishes … The edible-oil increase is found throughout Asia and Africa and the Middle East as a major source of change.” http://articles.orlandosentinel.com/2003-09-28/news/0309270148_1_overweight-or-obese-women-were-overweight-south-africa
Tom Brenna’s research suggests that the increase in vegetable oil intake is especially problematic for traditional vegetarian cultures. Excerpt:
“This mutation helps people convert plant fatty acids into important nutrients, including omega-6 arachidonic acid. Arachidonic acid is important for muscle growth and healthy neurological function in humans and is usually contained in meat, eggs and dairy. However, arachidonic acid is also known for its pro-inflammatory and pro-blood clotting properties. Today, this genetic mutation can be a problem because omega-6 fats are readily available in an increasing number of foods and oils. Consequently, people with this mutation are retaining higher levels of arachidonic acid in their blood and tissues.
https://www.researchgate.net/blog/post/human-genome-shaped-by-vegetarian-diet-increases-risk-of-cancer-and-heart-disease
When traditional vegetarians start eating more meat, the problem is exacerbated because arachidonic acid in the cell membranes of lean meat tissue is easily assimilated as explained in this video: https://www.youtube.com/watch?v=OfB3dAfEhCY
December 15, 2018 at 4:21 pm, Chester Draws said:
“When traditional vegetarians start eating more meat, the problem is exacerbated … ”
Your problem, not theirs, note.
These societies were traditionally largely vegetarian because they could not afford meat. They do not consider it a problem that they can now afford to eat more food and nicer food.
(Actual vegetarian societies don’t start eating meat, because that would literally mean they weren’t actually vegetarian. Brahmins weren’t vegetarian for lack of money.)
While I accept that obesity will start to become an issue down the track, for the moment giving poor people good food solves far more issues than it raises. We should most certainly not consider it a “problem” that people are less poor than they used to be.
December 16, 2018 at 3:44 am, Ted said:
Chester, these are helpful ideas and certainly better access to food is not the problem. However, leaving people in poverty with plenty of access to poor quality food is, in my opinion, an inadequate response to poverty. I favor doing more, not less, to address poverty and food insecurity.