Does the Vitamin and Mineral Content of Food Influence Our Food Intake and Body Fatness?

The Claim: We Overeat Because Our Diet is Low in Vitamins and Minerals

We know that animals, including humans, seek certain properties of food. Humans are naturally attracted to food that's high in fat, sugar, starch, and protein, and tend to be less enthusiastic about low-calorie foods that don't have these properties, like vegetables (1). Think cookies vs. plain carrots.

In certain cases, the human body is able to detect a nutritional need and take steps to correct it. For example, people who are placed on a calorie-restricted diet become hungry and are motivated to make up for the calorie shortfall (2, 3). People who are placed on a low-protein diet crave protein and eat more of it after the restriction is lifted (4). Humans and many other animals also crave and seek salt, which supplies the essential minerals sodium and chlorine, although today most of us eat much more of it than we need to. At certain times, we may crave something sweet or acidic, and pregnant women are well known to have specific food cravings and aversions, although explanations for this remain speculative. Research suggests that certain animals have the ability to correct mineral deficiencies by selecting foods rich in the missing mineral (5).

These observations have led to a long-standing idea that the human body is able to detect vitamin and mineral (micronutrient) status and take steps to correct a deficit. This has led to the secondary idea that nutrient-poor food leads to overeating, as the body attempts to make up for low nutrient density by eating more food. In other words, we overeat because our food doesn't supply the micronutrients our bodies need, and eating a micronutrient-rich diet corrects this and allows us to eat less and lose body fat. These ideas are very intuitive, but intuition doesn't always get you very far in biology. Let's see how they hold up to scrutiny.

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Food Reward Friday

This week's lucky "winner"... peanut M + M's!!!

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Does "Metabolically Healthy Obesity" Exist?

Obesity is strongly associated with metabolic alterations and negative health outcomes including diabetes, cardiovascular disease, and some types of cancer (1, 2, 3, 4). Excess body fat is one of the primary causes of preventable health problems and mortality in the United States and many other affluent nations, ranking in importance with cigarette smoking and physical inactivity. Obesity is thought to contribute to disease via the metabolic disturbances it causes, including excess glucose and lipids in the circulation, dysregulated hormone activity including insulin and leptin, and inflammatory effects. This immediately raises two questions:

1. Does metabolically healthy obesity exist?
2. If so, are metabolically healthy obese people at an elevated risk of disease and death?

Does metabolically healthy obesity exist?

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The Higher Ed STEM Myth

In Malcolm Gladwell�s recent book David and Goliath, he repeats the following common claim: �At a time when students with liberal arts degrees struggle to find jobs, students with STEM degrees are almost assured of good careers.� The only problem with this idea is that it is at best misleading and possibly completely false. Looking at recent labor data and multiple research studies, it appears that at the very moment the Obama administration and most state officials are pushing for a rapid increase in students holding college degrees in Science, Technology, Engineering, and Math, most jobs in these areas have faced stagnant wages and decreased job opportunities.

According to the article, �The STEM Crisis is a Myth�, �there are more STEM workers than suitable jobs. One study found, for example, that wages for U.S. workers in computer and math fields have largely stagnated since 2000. Even as the Great Recession slowly recedes, STEM workers at every stage of the career pipeline, from freshly minted grads to mid- and late-career Ph.D.s, still struggle to find employment as many companies, including Boeing, IBM, and Symantec, continue to lay off thousands of STEM workers.�  In face of this decrease in STEM-related job opportunities, we are reminded that, �President Obama has called for government and industry to train 10,000 new U.S. engineers every year as well as 100,000 additional STEM teachers by 2020. And until those new recruits enter the workforce, tech companies like Facebook, IBM, and Microsoft are lobbying to boost the number of H-1B visas�temporary immigration permits for skilled workers�from 65,000 per year to as many as 180,000.�  In other words, high-tech companies are pushing for increased access to high-skilled foreign workers in order to drive down labor costs and produce a more competitive labor market.  Meanwhile, government officials are calling for a massive increase in funding to educate people for jobs that do not exist.

One of the major reasons why the government seems to have it all wrong is the way STEM jobs are defined: �According to Commerce, 7.6 million individuals worked in STEM jobs in 2010, or about 5.5 percent of the U.S. workforce. That number includes professional and technical support occupations in the fields of computer science and mathematics, engineering, and life and physical sciences as well as management. The NSF, by contrast, counts 12.4 millionscience and engineering jobs in the United States, including a number of areas that the Commerce Department excludes, such as health-care workers (4.3 million) and psychologists and social scientists (518,000).�  The first problem is then the US government itself has conflicting ways of defining who is working in a STEM job, and thus the National Science Foundation is able to call for more STEM funding by including in its ranks, healthcare workers, psychologists, and social scientists.  However, if we look at the more traditional understanding of STEM jobs, which is used by the Commerce Department, only 5.5% of all current US jobs fall into this area. 

Not only is the STEM crisis being pushed by bad data and loose definitions, but it is also being fueled by a massive misunderstanding regarding the relationship between college degrees and future employment: �Of the 7.6 million STEM workers counted by the Commerce Department, only 3.3 million possess STEM degrees. Viewed another way, about 15 million U.S. residents hold at least a bachelor�s degree in a STEM discipline, but three-fourths of them�11.4 million�work outside of STEM.� Thus, not only are there limited employment opportunities in the STEM areas, but most of the people with STEM degrees do not work in STEM jobs, and most of the people working in STEM jobs do not have STEM degrees. This mismatch between degrees and jobs means that there is not a pressing need to produce more people with STEM degrees, and non-STEM degree holders often end up being employed in STEM jobs. 

One reason why the STEM labor market is hard to predict and plan for is because of the business and labor practices dominating these areas: �Highly competitive science- and technology-driven industries are volatile, where radical restructurings and boom-and-bust cycles have been the norm for decades. Many STEM jobs today are also targets for outsourcingor replacement by automation.� It turns out that the celebrated jobs in the STEM areas are highly susceptible to downsizing, outsourcing, and boom-and-bust business cycles. 

The unstable nature of STEM jobs is matched by the short-term thinking of many high-tech companies: �In engineering, for instance, your job is no longer linked to a company but to a funded project. Long-term employment with a single company has been replaced by a series of de facto temporary positions that can quickly end when a project ends or the market shifts. To be sure, engineers in the 1950s were sometimes laid off during recessions, but they expected to be hired back when the economy picked up. That rarely happens today. And unlike in decades past, employers seldom offer generous education and training benefits to engineers to keep them current, so out-of-work engineers find they quickly become technologically obsolete.� Like so many other fields and professions, the older model of career employment has been replaced by a new system of just-in-time flexible labor, which in turn, reduces the opportunity for job advancement since companies do not want to invest in workers who have no future with their corporations.

Like the employment practices in higher education, wages in the STEM areas are being pushed down by an over-supply of future workers and an under-supply of new good jobs: �if you apply the Commerce Department�s definition of STEM to the NSF�s annual count of science and engineering bachelor�s degrees, that means about 252,000 STEM graduates emerged in 2009. So even if all the STEM openings were entry-level positions and even if only new STEM bachelor�s holders could compete for them, that still leaves 70,000 graduates unable to get a job in their chosen field. Of course, the pool of U.S. STEM workers is much bigger than that: It includes new STEM master�s and Ph.D. graduates (in 2009, around 80 000 and 25 000, respectively), STEM associate degree graduates (about 40 000), H-1B visa holders (more than 50 000), other immigrants and visa holders with STEM degrees, technical certificate holders, and non-STEM degree recipients looking to find STEM-related work. And then there�s the vast number of STEM degree holders who graduated in previous years or decades.�  If you work at a university and college, this story should be very familiar; in the face of decreased job opportunities, colleges continue to flood the market with new workers, which then functions to drive down wages and create a class of underemployed and unemployed degree-holders.  

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Food Reward Friday

This week's lucky "winner"... Oreo cookies!!!

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Beans, Lentils, and the Paleo Diet

As we continue to explore the foods our ancestors relied on during our evolutionary history, and what foods work best for us today, we come to legumes such as beans and lentils. These are controversial foods within the Paleolithic diet community, while the broader nutrition community tends to view legumes as healthy.

Beans and lentils have a lot going for them. They're one of the few foods that are simultaneously rich in protein and fiber, making them highly satiating and potentially good for the critters in our colon. They're also relatively nutritious, delivering a hefty dose of vitamins and minerals. The minerals are partially bound by the anti-nutrient phytic acid, but simply soaking and cooking beans and lentils typically degrades 30-70 percent of it, making the minerals more available for absorption (Food Phytates. Reddy and Sathe. 2002). Omitting the soaking step greatly reduces the degradation of phytic acid (Food Phytates. Reddy and Sathe. 2002).

The only tangible downside to beans I can think of, from a nutritional standpoint, is that some people have a hard time with the large quantity of fermentable fiber they provide, particularly people who are sensitive to FODMAPs. Thorough soaking prior to cooking can increase the digestibility of the "musical fruit" by activating the sprouting program and leaching out tannins and indigestible saccharides. I soak all beans and lentils for 12-24 hours.

The canonical Paleolithic diet approach excludes legumes because they were supposedly not part of our ancestral dietary pattern. I'm going to argue here that there is good evidence of widespread legume consumption by hunter-gatherers and archaic humans, and that beans and lentils are therefore an "ancestral" food that falls within the Paleo diet rubric. Many species of edible legumes are common around the globe, including in Africa, and the high calorie and protein content of legume seeds would have made them prime targets for exploitation by ancestral humans after the development of cooking. Below, I've compiled a few examples of legume consumption by hunter-gatherers and extinct archaic humans. I didn't have to look very hard to find these, and there are probably many other examples available. If you know of any, please share them in the comments.

To be clear, I would eat beans and lentils even if they weren't part of ancestral hunter-gatherer diets, because they're inexpensive, nutritious, I like the taste, and they were safely consumed by many traditional agricultural populations probably including my own ancestors.

Extensive "bean" consumption by the !Kung San of the Kalahari desert

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Protesting, Dissent, and Unionization

November ^20th was a perplexing day for some on the UC campuses.  As AFSCME and UAW held a joint strike, many students and media people wanted to know why graduate students would go out on strike to support mostly manual workers.  Of course, the reason for this support was that both unions were protesting against the sense that the UC administration does not respect collective action and collective bargaining.  Moreover, what really scares and confuses many people in power is the sight of seeing both service and professional workers protesting together.

People in power must know that a coalition of organized professional and service workers could be one of the only groups strong enough to stop the neoliberal political economy, and when you throw recent immigrants and indebted students into the mix, a very threatening progressive coalition emerges. Although some may say that the protests and strike were really only about pensions and pay, it is clear that a more fundamental democratic yearning was evident in these actions. Not only do workers and students feel that they do not have a voice at their own institutions, but they also feel alienated by the silent forces of global capitalism and austerity politics.

AFSCME did a very smart thing by working with various student groups to form a diverse coalition of workers, students, and faculty, and while the peaceful demonstrations did not generate much police presence, recent trends suggest that once organized dissent becomes visible and disruptive, it will be countered in a forceful way.  Let us hope that this is the beginning of a more forceful organization of the people who make this university work.

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