Who is really watering the roots of obesity?

Posted: September 27, 2012 in Policy, Science

The United States is experiencing childhood obesity levels like never before seen, and these ever increasing numbers have left many searching for the causes of this public health disaster. Theories range from ‘overweight people are just lazy’ to ‘it’s the governments fault’ to ‘parents are to blame’ to ‘obesity is a disease of addiction.’ Which theory is correct? How do we take steps to stop this rising rate of obesity?

According to the Centers for Disease Control, 12.5 million Americans ages 2-19 years of age are obese. That’s 17% of the US population! To me, an even more alarming statistic is that in the past 30 years, the prevalence of childhood obesity has almost tripled. Obesity dramatically increases the likelihood of a variety of diseases such as type II diabetes and cardiovascular diseases and results in a decreased life expectancy. Additionally, obesity costs the US hundreds of billions of dollars each year. Add to this the psychological stress obese people experience because of the negative stigma associated with being overweight and we have a serious health crisis on our hands.

The most commonly accepted cause of obesity is the intake of excessive food energy without the accompaniment of the appropriate level of energy expenditure. Before I get too far into this post, let me make clear that this post is focused on non-medically induced obesity. A variety of medical issues such as low metabolism and endocrine disorders lead to obesity, regardless of food intake or exercise levels. Additionally, I realize that overweight does not necessarily mean unhealthy and there are plenty of thin people who can be considered as unhealthy. The US is definitely too obsessed with thin as being the ideal, and people definitely come in all shapes and sizes. That being said, there is a large portion of the US population who are obese but not because of any known medical condition, and the fact that hundreds of thousands of Americans die each year because of obesity related issues cannot be ignored. The question this post is trying to address is ‘why exactly are so many people becoming obese?’.

Increased consumption of food energy has mirrored the increased prevalence of obesity. The CDC reports, “During 1971–2000, a statistically significant increase in average energy intake occurred.” The report’s editorial note reads, “The increase in caloric intake described in this report is consistent with previously reported trends in dietary intake in the United States. USDA survey data for 1977–1996 suggest that factors contributing to the increase in energy intake in the United States include consumption of food away from home; increased energy consumption from salty snacks, soft drinks, and pizza; and increased portion sizes”. Highly palatable (tasty) foods such as chips and soda are more energy dense, they contain less nutrients and water but have increased fat and sugar. The passage of the US Farm Bill created subsidies for certain food crops grown in the US, such as corn, soybeans, and wheat. Michael Pollan, author of the The Omnivor’s Dilemma, writes, “The result? A food system awash in added sugars (derived from corn) and added fats (derived mainly from soy), as well as dirt-cheap meat and milk (derived from both). By comparison, the farm bill does almost nothing to support farmers growing fresh produce. A result of these policy choices is on stark display in your supermarket, where the real price of fruits and vegetables between 1985 and 2000 increased by nearly 40 percent while the real price of soft drinks (a k a liquid corn) declined by 23 percent. The reason the least healthful calories in the supermarket are the cheapest is that those are the ones the farm bill encourages farmers to grow.”

Now for the important statistic I neglected to mention above. Ethnic background and socioeconomic status are major factors for obesity. The CDC estimates that 1 in 3 low-income children are overweight or obese and American Indian and Hispanic children have the highest obesity levels. Thanks to the Farm Bill, energy dense food is cheap. Add to this that “food deserts,” areas where access to healthy food such as fresh produce is limited and access to unhealthy food such as those found at a fast food restaurant or corner stores is plentiful, have been seen increasingly in low-income and rural areas. Plus, as MakingHealthEasier.org explains, “The average restaurant meal today is more than four times larger than in the 1950s.” Oh, and don’t forget that, as NPR reports, the 2010 census showed the highest levels of poverty and lowest levels of income in 17 years. So is it really any surprise that children of low socioeconomic status have the highest rates of obesity or that obesity rates continue to increase despite numerous anti-obesity campaigns?

Ok, so we now understand that junk food is a leading cause of obesity and because it is cheap and easily accessible it is increasingly the go-to food for much of the US. I want to switch gears for a bit and discuss the potential for obesity as an addiction type of disorder. Is food, like crack or alcohol, just some addicts “drug” of choice? A recent review in Nature Neuroscience discusses the similarities and differences between so called food addiction and drug addiction. People find highly palatable food rewarding, just like cocaine or alcohol can be rewarding. Rodents will work for a sugar reward and will increase their intake in a similar pattern to that seen for drugs of abuse. But results are mixed, and not all aspects of drug addiction are mirrored by food reward. For example, stress often leads to drug relapse, but in rodent models, stress exposure generally results in decreased food intake and eventual anorexia.

A leading theory of drug addiction is that drugs of abuse such as cocaine or heroine highjack the brain’s natural reward pathway and alter the neuronal connections in a way to increase the importance of environmental cues that have been previously linked to drug use. For example, if a cigarette smoker used to buy their cigarettes from the same corner store everyday, driving past that corner store years later can be enough to cause that person to start smoking again, even if they had been abstinent for an extended period of time. Could it be that the rewarding properties of highly palatable foods also highjack a person’s reward pathway so that when they see a fast food sign they are driven to seek out that specific food? During childhood and adolescence the brain, especially brain areas associated with reward and complex decision making, is still going through a significant amount of development and maturation. This high level of maturation during the early years of life renders the brain more susseptible to damage by external insults. For example, adolescent alcohol use has been associated with later problem drinking and risk taking behavior in adulthood. Could the easily accessible and cheap availability of energy dense food during childhood induce changes to the brain’s reward systems to the point of permanently affecting the way a person responds to certain types of food? Could highly palatable food intake as a child hardwire a person’s brain to habitually seek out that type of food to the point where, even after extended periods of abstinence, relapse occurs easily and is common? Much additional research will be required before these types of  questions can be answered, and I am only speculating at this point, but it is a frightful notion that because of policy surrounding food crops in the US, we may be basically setting up our children, especially children from low-income families, for a life of junk food “addiction.”

So what can be done? Well, the Farm Bill happens every five years, and being that the last one was passed in 2008, we are due for a new one. Surprise, surprise, partisan gridlock has ensured that the Farm Bill will not be passed prior to the elections in November. While I find the lack of productivity by congress extremely frustrating, people should also realize that we have a chance to alert the American public to what farm subsidies established by the Farm Bill are doing to the health of the general public. Many science advocacy groups such as the Union of Concerned Scientists are pushing for a dramatically revised Farm Bill that includes the increased production of healthy and accessible food. First Lady Michelle Obama’s “Let’s Move” campaign to fight childhood obesity has also taken up the cause. Sadly, but not surprisingly, an even larger number of pro big agribusiness organizations are lobbying for the exact opposite. According to the Center for Responsive Politics, agribusiness spent almost $150 million lobbying in 2008. Oh, and did I forget to mention that now with the FDA’s approval of anti-obesity drugs Qsymia and Belviq, pharmaceutical companies with deep pockets will most likely become major players in the Farm Bill debate.

Lindy West of Jezebel wrote a scathing article discussing the horrible ways that Blue Cross and Blue Shield of Minnesota’s new anti-obesity campaigns are actually anti-fat people campaigns. She writes, “It would be possible to make a commercial calling for more accountability and transparency in food production and food marketing—the way that corporations and agribusiness feed people poison and call it nutrition. It would be possible to create healthy food that the poorest Americans can afford. All of this is possible. But instead, Plan A is to punish the people?” While I definitely do not appreciate the way Ms. West seems to downplay the very serious nature of rising obesity rates, I do agree with her that a campaign against the American public will get us no where. A campaign against subsidies for junk food crops might. A Congress that actually does work and can stand up against the millions of dollars big agribusiness puts into its lobbying efforts would also help. So, as usual, my bottom line is to get involved, vote for leaders who support healthy lifestyles and sustainable and healthy food production, vote for individuals who don’t have big business whispering in their ear to the tune of campaign donations. Talk to your elected officials to inform them of your desire for a vastly revamped Farm Bill. Support organizations like the Union of Concerned Scientist. Vote.

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Comments
  1. One topic I didn’t cover in this post (it was already getting quite long!), was that the Farm Bill also sets policy for the Supplemental Nutrition Assistance Program (SNAP) (food stamps). Children benefit from SNAP in the form of free school lunches, but there is a long history of lobbying against healthy lunches (expl. the potato industry has successfully lobbied to block legislation that would limit the servings of potatoes to twice a week; pizza sauce counts as a vegetable).

    New guidelines for school lunches were announced earlier this year, but the pushback has been significant. A major issue with the new regulations has been that there are now calorie limits (850 for post-elementary school) and kids are complaining that they are hungry. The new regulations allow for as many fruits and vegetables as the children want, additionally, as the Huffington Post reports, “Kristi King, spokesperson for the Academy of Nutrition and Dietetics, tells the network that the whole grain and fiber-robust new lunches should actually keep students fuller than before, “if they are actually consuming the whole product.”” (http://www.huffingtonpost.com/2012/09/28/school-lunch-fight-jon-st_n_1922703.html).

    NPR has an article today (http://www.npr.org/blogs/thesalt/2012/09/28/161941282/some-grumble-about-change-as-school-lunches-get-leaner-and-greener) discussing the issues surrounding the new regulations. The final paragraph reads, “All three women agree that in time, most kids will be on board with what’s on their lunch trays. “Kids who are in kindergarten today are going to start out with school food that is high quality,” says Saenz Tobey. “Those kids will grow up knowing that that’s what school food is.””

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