Scientific American Topic - Obesity

Breast Milk Is Best for Newborns, but the Bottle Is Fine, Too

Fri, 06 Nov 2009 00:00:00 EST

Dear EarthTalk: What are the pros and cons of feeding babies formula versus breast milk? And if I purchase formula, should I spend the extra money on the organic variety? --Suzy W., via e-mail [More]

Dieting and the TV-to-Treadmill Ratio

Tue, 27 Oct 2009 09:27:08 EST

[ The following is an exact transcript of this podcast. ]

If you want to lose weight--really lose it and keep it off--look around your house. How many TV sets are there? And is there an exercise bike or any other similar equipment? The answers could predict the success of your weight loss quest, according to a report in the Annals of Behavioral Medicine. [More]

Lard Lesson: Why Fat Lubricates Your Appetite

Mon, 19 Oct 2009 17:00:00 EST

When you've spent the weekend splurging on greasy fast foods, your bathroom scale isn't alone in reeling from the impact. Your brain does, too. New research shows just how saturated fat tricks us into eating more and elucidates the evolutionary basis for the propensity for poundage in developed nations. Our brain physiology, it seems, is glaringly out-of-date in the modern world.

[More]

When the Economy Is in the Red, Are People Really in the Pink?

Sat, 10 Oct 2009 10:15:00 EST

Unemployment reached 23 percent and the GDP shrank by as much as 14 percent, so it's hard to imagine a silver lining to the tumultuous years of the Great Depression . But could the general health of the U.S. population actually have improved when the nation's economic fitness took multiple nosedives? And, if a floundering economy improves longevity, what does this say about our current recession? [More]

Breast cancer deaths drop over past two decades

Thu, 01 Oct 2009 23:15:00 EST

The number of women who die from breast cancer has decreased slowly (about 2 percent per year) but steadily since 1990, according to a new report by the American Cancer Society (ACS), released to mark the start of Breast Cancer Awareness Month. [More]

The Effect of Our Surroundings on Body Weight

Wed, 30 Sep 2009 09:00:00 EST

Obesity is a “global epidemic,” according to the World Health Organization. Two thirds of American adults and one third of school-age children are either overweight or obese (defined as extremely overweight). These proportions have been rising steeply, report the latest surveys. From 1960 to 2002 the population of overweight and obese adults increased by roughly 50 percent, and the corresponding increase for children was 300 percent. Compounding the problem, obesity rates in other countries are rapidly approaching those in the U.S.

What is causing this pandemic, and what can we do about it? Researchers have provided some tentative answers that fly in the face of commonly held beliefs. They suggest that the increase in obesity may be a result of environmental changes that tempt us into unhealthy habits and tend to overwhelm our psychological defenses against consuming too much and succumbing to fattening fare. In fact, environmental cues can exacerbate any innate tendency to use food as a balm for jittery nerves or sadness. Thus, many health experts advocate legislation--for instance, a tax on junk food--that promotes healthy eating. Others are trying to help individuals change their immediate eating milieu in ways that discourage overeating.

[More]

Inflammation Brings on the Blues

Thu, 24 Sep 2009 10:00:00 EST

As if being stuck sick in bed wasn’t bad enough, several studies conducted during the past few years have found that the immune response to illness can cause depression. Recently scientists have pinpointed an enzyme that could be the culprit, as it is linked to both chronic inflammation--such as that found in patients with coronary heart disease, type 2 diabetes and rheumatoid arthritis--and depressive symptoms in mice.

In the new study, immunophysiologist Keith Kelley and his colleagues at the University of Illinois exposed mice to a tuberculosis vaccine that produces a low-grade, chronic inflammation. After inoculation, production in the mice brains of an enzyme called IDO, which breaks down tryptophan, spiked. The animals exhibited normal symptoms of illness such as moving around and eating less. Yet even after recovering from the physical illness induced by the vaccine, they showed signs of depression--for example, struggling less than control mice to escape from a bucket of water. Surprisingly, their listlessness was solved relatively simply. “If you block IDO, genetically or pharmaceutically, depression goes away” without interfering with the immune response, Kelley explains.

[More]

Groups as Therapy?--Socializing and Mental Health (preview)

Wed, 09 Sep 2009 10:00:00 EST

You have turned up for your annual medical checkup. The doctor has taken your blood pressure, inquired about your diet and exercise patterns, and asked whether you smoke. Then come some rather pointed questions about your social life: Do you have many friends? Do you socialize? Which groups do you belong to? How diverse are they? How important are these groups to you?

Even though these questions are unexpected, you go through the long list of your active memberships: your book club, volleyball team, hiking group, work colleagues, and so on. Your doctor congratulates you and says that you are doing exactly the right things. You even learn that because you belong to so many social groups you should not worry if you skip your gym visit every now and then.

[More]

Body clock linked to weight gain

Thu, 03 Sep 2009 10:10:00 EST

That midnight trip to the fridge might be doing double damage. Most people know by now that it's poor dietary form to eat right before bed, but the body's natural circadian rhythm and related rest cycles might also have more to do with weight gain than previously thought, according to a study published online today in the journal Obesity . [More]

Origins of Everything: The September Scientific American Magazine

Mon, 31 Aug 2009 19:50:08 EST

Scientific American Editor in Chief Mariette DiChristina discusses the September special single-topic issue of Scientific American magazine, which covers origins, from the universe to the horse stirrup. Plus, we'll test your knowledge of some recent science in the news. Web sites related to this episode include www.thelongtail.com

Podcast Transcription

[More]

Semi-sweet: Americans should cut sugar consumption by more than half, says AHA

Tue, 25 Aug 2009 13:40:00 EST

The average American consumes about 22 teaspoons ( 355 calories ) of added sugar a day, according to a report released yesterday by the American Heart Association (AHA). That amount should be cut down to a maximum of six teaspoons (100 calories) a day for women and nine teaspoons (150 calories) for men, the group recommends. [More]

Depression's Evolutionary Roots

Tue, 25 Aug 2009 09:00:00 EST

Depression seems to pose an evolutionary paradox. Research in the US and other countries estimates that between 30 to 50 percent of people have met current psychiatric diagnostic criteria for major depressive disorder sometime in their lives. But the brain plays crucial roles in promoting survival and reproduction, so the pressures of evolution should have left our brains resistant to such high rates of malfunction. Mental disorders should generally be rare -- why isn’t depression?

[More]

To Bee or Not to Bee

Fri, 21 Aug 2009 21:00:08 EST

In part 2 of our bee podcast, we talk with May Berenbaum, entomologist at the University of Illinois at Urbana–Champaign and inspiration for the X Files fictional entomologist Bambi Berenbaum, about bees, other insects and how life history analysis can make us rest easy during scary sci-fi invasion movies. Plus, we'll test your knowledge about some recent science in the news.

Podcast Transcription

[More]

Severe Sleep Apnea May Bring Greater Risk of Death for Some

Tue, 18 Aug 2009 15:30:00 EST

Brief periods of interrupted breathing during sleep affect an estimated 10 to 25 percent of people in the U.S. A smattering of studies have linked the condition, known as obstructive sleep apnea, to a host of serious health risks, such as cardiovascular disease, obesity and even accidents--but long-term, population-based data on mortality overall have been lacking. [More]

Do food stamps lead to obesity?

Tue, 11 Aug 2009 16:15:00 EST

One out of every nine people now receives food stamps in the U.S. And two thirds of Americans are either overweight or obese . A new scientific study links these startling figures and suggests that food stamps may actually be a risk factor for obesity. [More]

Are Contaminants Silencing Our Genes?

Mon, 03 Aug 2009 13:10:00 EST

Each of us starts life with a particular set of genes, 20,000 to 25,000 of them. Now scientists are amassing a growing body of evidence that pollutants and chemicals might be altering those genes--not by mutating them, but by sending subtle signals that silence them or switch them on at the wrong times. [More]

A Patchwork Mind: How Your Parents' Genes Shape Your Brain (preview)

Wed, 29 Jul 2009 09:00:00 EST

Your memories of high school biology class may be a bit hazy nowadays, but there are probably a few things you haven’t forgotten. Like the fact that you are a composite of your parents--your mother and father each provided you with half your genes, and each parent’s contribution was equal. Gregor Mendel, often called the father of modern genetics, came up with this concept in the late 19th century, and it has been the basis for our understanding of genetics ever since.

But in the past couple of decades, scientists have learned that Mendel’s understanding was incomplete. It is true that children inherit 23 chromosomes from their mother and 23 complementary chromosomes from their father. But it turns out that genes from Mom and Dad do not always exert the same level of influence on the developing fetus. Sometimes it matters which parent you inherit a gene from--the genes in these cases, called imprinted genes because they carry an extra molecule like a stamp, add a whole new level of complexity to Mendelian inheritance. These molecular imprints silence genes; certain imprinted genes are silenced by the mother, whereas others are silenced by the father, and the result is the delicate balance of gene activation that usually produces a healthy baby.

[More]

Do Contaminants Play a Role in Diabetes?

Mon, 20 Jul 2009 16:30:00 EST

Eat right and exercise, conventional wisdom has it, if you want to avoid joining the diabetes epidemic.

But a new study adds some muscle to a growing body of research suggesting those steps, though beneficial, might not be enough for people exposed to chemicals in the environment.

[More]

News Scan Briefs: Do Rain Forests Make Rain?

Tue, 14 Jul 2009 07:00:00 EST

A Lower High-Water Mark The maximum global sea-level rise from the collapse of the rapidly warming West Antarctic ice sheet may be 3.2 meters--not five meters or more as predicted in the past. The revision comes from a new model suggesting that only parts of the ice sheet will collapse--namely, those that are grounded below sea level or sloping downward. Areas of the sheet grounded above sea level or on upward-sloping bedrock would remain in place. The results, in the May 15 Science , say nothing about disappearing ice sheets elsewhere, however. Greenland, for instance, holds enough ice to raise sea levels by seven meters. --David Biello

[More]

Popularity is In Your Genes

Thu, 09 Jul 2009 09:00:00 EST

We take it for granted that certain aspects of our social behavior--whether we chat easily with strangers at a party, for instance, or prefer to be a wallflower--are influenced by genetics. But now researchers at the University of California, San Diego, and Harvard University have shown that genes have a much broader sway, affecting the kinds of social networks people form and the positions they occupy in them.

James Fowler, a political scientist at U.C.S.D., and his colleagues studied the social networks of 1,110 adolescent fraternal and identical twins. They found that three aspects of the twins’ social networks appeared to be shaped by genetics. How many times each teen was named by others as a friend and how likely each youth’s friends were to know one another were both approximately 50 percent related to genetic factors. Whether a teen was located at the center of a network or toward the edge was about 30 percent genetic.

[More]