First, I’ll ask you to consider these two maps of the US. One is of obesity trends in the US in 1991 and the other is of obesity trends in the US in 2009. The percents represent the percent of people in that state who are obese. What do you notice? Look at the color of your state in each map.
1991 Obesity Trends, US
2009 Obesity Trends, US
Something happened over the last 2 decades. The nation gained weight. Why? Who is to blame? Is your weight your fault? Many people believe that obesity is a result of poor personal choices or lack of will power. The contention is that if you really wanted to, you could choose to be lean by eating healthy and getting enough exercise to maintain a healthy weight. We have free will after all. If you have not maintained a healthy weight, you have simply not exercised your free will to do so. Right? Politicians fighting against health care and other policies relating to obesity have suggested that each citizen has a “personal responsibility” to maintain a healthy weight and that there is no need for the government to intervene. Senator Shane Cultra (IL-R) was quoted just this week as saying, “It’s the parents’ responsibility that have obese kids. I think you need to look at a bill to take the tax deduction away for their child if he’s obese. In poorer families, they actually get money for their kids. I’d take that money away.” He was suggesting that the standard child tax deduction of $2000 be revoked for parents of obese children because they should be punished for not taking responsibility of their children’s weight. When pressed later, he said he was kidding about the tax and only trying to make the point that it is the parent’s responsibility to keep their children from being obese. It’s not just politicians. A sample of dietitians ranked “lack of willpower” as more important to the development of obesity than genetic factors (Harvey et al 2002), even though adult body mass is 55-75% genetic. So are they right? Is it a matter of personal responsibility? Is your weight your own damn fault?
If it is, apparently our sense of personal responsibility has come apart in the last few decades, along with our parenting skills. Can this be?
The research on causes of the obesity epidemic cite a multitude of factors that have changed over the last few of decades, coinciding with increasing weight. In addition to coinciding with increasing weight, these factors also have strong evidence for a causal impact on weight. Interestingly, our lagging personal responsibility and shoddy parenting skills did not make the list.
1. Drugs. Weight gain is associated with several commonly used medications that were originally introduced into the market in the last 2-3 decades, including psychotropic medications, antidiabetics, antihypertensives, steroid hormones and contraceptives, antihistamines, and protease inhibitors. All of these medications have weight gain side effects and many also have metabolic effects (see McAllister et al 2009 for a review). Rates of use of these known weight gain agents are associated with increasing weight over time.
2. Ambient temperature – Lower ambient temperature is related to greater food consumption. Homes with air conditioning have increased dramatically over the last few decades (McAllister et al 2009). Ever notice it’s freezing in restaurants? They know you’ll eat more. Keep in mind also that our metabolisms rise with higher temperatures (not lower).
3. Maternal birth age – Women are having children at an increasingly older age over the last few decades. Unfortunately, higher maternal birth age is related to higher body mass index of the child (McAlllister et al 2009).
4. Sleep Deprivation – Average sleep time has decreased dramatically in recent decades. Sleep deprivation is related to increased appetite, weight gain, and less physical activity (McAllister et al 2009).
5. Chemicals –Certain chemicals that have increased in use are known as endocrine disrupters (which has metabolic/weight gain implications) and include pesticides, plasticizers, flame retardant, plant estrogens, and industrial byproducts (PCBs, dioxins) (McAllister et al 2009).
6. Smoke Free – The smoking epidemic has subsided with smoking rates declining from 42% in 1965 to 20% in 2005. Smoking rates leveled off between 2005-2010. Weight gain often follows smoking cessation and may account for some increasing body weight over time.
7. Restaurant dining – The number of meals you consume at a restaurant is correlated with your body mass index (Bo et al 2011). The frequency of dining out has dramatically increased in recent decades and restaurant portion sizes have risen.
8. Grocery Bill – Look at the change in retail price of various foods from 1985-2000 in this table (Drewnowski et al 2005). What has increased the most? What has increased the least? Why?
Sodas, fats, and sweets have increased in price the least, and fruit and veggies the most! In fact, the largest government subsidy of foods is for corn at $42 billion annually. Corn is mainly used to feed livestock (beef), and to produce…wait for it… high fructose corn syrup, an inexpensive and widely used sweetener in many food products. From 1975-1997 per capita consumption of HFCS increased to an equivalent of 200 kcal/day per person in the US. When politicians and others speak against anti-obesity policies using the argument that the government should not tell us what we can and can’t eat, they are ignoring the fact that the government has been doing this all along with the types of food they subsidize. Suggesting that putting a tax on sodas, for example, is government meddling seems silly in light of the government’s impact on food costs via subsidies.
These factors make up only a few of those cited in the research literature as contributing to our increasing body weights over the last few decadses. This post would be pages if I were to review them all. In considering all of the factors that are converging to affect our weight, it is difficult to tell who is “responsible.” If our weight is a matter of our free will, how can we exercise free will when we have little awareness of the causes of our weight gain? Perhaps you gained 30 pounds after going on an antidepressant medication and quitting smoking. Did you “will” that weight on? Not likely. You probably weren’t even aware of the impact of these things on your weight.
The increasing rate of obesity in our nation is multi-factorial, being affected by economic, biologic, societal, medical, and lifestyle factors. Each individual can try the best they can to attempt to overcome these forces, a challenge that may be quite difficult for some, especially those with genetic vulnerabilities that make weight loss especially difficult. However, the ultimate solution to the epidemic of obesity in our nation will not be at the level of the individual. This one is gonna take a village.
Harvey EL, Summerbell CD, Kirk SF, Hill AJ. Dietitians’ views of overweight and obese people and reported management practices. J Hum Nutr Diet 2002;15:331-347.
McAllister, E.J. et al (2009). Ten putative contributors to the obesity epidemic. Crit Rev Food Sci Nutr, 49(10), 868-913.
Bo, S. et al (2011). Contributors to the obesity and hyperglycemia epidemics. A prospective study in a population-based cohort. International Journal of Obesity. Epub Ahead of print.