Purdue Science & Health Briefs
Purdue Science & Health Briefs
WEST LAFAYETTE, Ind. -- A comparison of data on fast-food consumption and rising obesity has found a surprising wrinkle: There doesn't appear to be much of a link, at least in terms of large populations.
James Binkley, associate professor of agricultural economics at Purdue University, used state-by-state data to examine one bit of dogma in the war on weight -- that the nation's increasing fast food consumption is partly to blame for the widespread rise in adult obesity. He found that "states that have a lot of fast-food sales aren't the states that the Centers for Disease Control say have weight problems."
Binkley presented his findings at the annual meeting of the Western Agricultural Economics Association July 16 in Reno, Nev. The research was funded by Purdue.
"One conclusion that I would derive from this data is that changing exercise habits could be more to blame than diet," Binkley says. "It may be couch potatoes, not french fries, that are the heart of the problem."
There is little doubt that obesity is a burgeoning problem in the United States. Between 1960 and 1991, the number of adults who were overweight increased from 25 percent to 33 percent, according to the U.S. government's 1995 "Third Report on Nutrition Monitoring in the United States, Volume I."
Binkley compared data from the Centers for Disease Control's (CDC) Behavioral Risk Factor Surveys with the 1992 Census of Retail Trade using data for states and regions. This data was compared with the prevalence of fast-food restaurants in these states and regions.
The general assumption in media reports and among some nutritionists is that fast food leads to obesity, Binkley says. That is what Binkley expected to find when he compared the data. "It wouldn't have surprised me to find that there isn't any relationship at all at this level," he says. "But what we found was a slightly negative association. There certainly wasn't a positive relationship."
In other words, people living in states with high numbers of fast-food outlets were slightly less likely to be obese than people living in states with fewer fast-food outlets, according to the study.
According to Binkley, the study confirms that the problem of obesity is a confoundingly complex one. At most, the study suggests that the types of food one eats may not matter as much as the amount of calories consumed or the amount of exercise. "Fast-food restaurants may be to blame in some way for the nation's weight problems, but in general there is little evidence of that," he says.
Taking the study one step further, Binkley then compared the CDC data with the 1990 Sales Area Marketing Inc. (SAMI) data on warehouse grocery sales. Again, he found little correlation between types of food consumption and obesity.
"Actually, I couldn't find much of a relationship at all between long-term dietary changes and increasing obesity," Binkley says.
The data from the grocery wholesalers showed that populations that consume convenience foods and trendy foods such as jarred peppers or black olives are less likely to be obese than groups that consume more traditional foods such as canned goods, frankfurters or pudding.
Randy Gretebeck, a registered dietitian and exercise physiologist in Purdue's Department of Foods and Nutrition, says it's not uncommon for large studies to provide results that confound nutritionists. "Large studies have found that food intake doesn't seem to be a good indicator of obesity, but we know it should be. Also, recent studies have found that fat consumption has gone down across the nation, yet obesity continues to increase," he says. "Right now, more and more people are pointing to decreasing physical activity as a reasonable explanation."
Besides reduced activity and exercise, Gretebeck says, there may be other possible explanations for the seeming anomaly, "and what we really need to do is to investigate further."
CONTACTS: Binkley, (765) 494-4261; e-mail, james.k.binkley.1@purdue.edu; Gretebeck, (765) 494-8792; e-mail gretebeckr@cfs.purdue.edu
NOTE TO JOURNALISTS: A color photo of Dr. Robert "Pete" Bill and some students examining an equine digestive tract is available. Ask for the photo called Bill/Vetcourse.
WEST LAFAYETTE, Ind. -- Purdue University has added a new twist to a recent trend in training veterinarians.
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"Conventional wisdom says it's 'all or nothing' when it comes to this type of teaching and learning," says Dr. Robert "Pete" Bill, assistant professor of clinical pharmacology who helped design the curriculum. "That's why Cornell and Mississippi State universities converted a large portion of their curriculums. We've done it with a very specific portion of our veterinary program and created a hybrid of sorts."
Purdue students take a new problem-solving class over four consecutive semesters during the first half of their academic careers.
"I think we're offering our students the best of both worlds," Bill says. "They get traditional classroom instruction and an opportunity to put it to use at the same time. It helps them realize that they are learning for their profession, not just next week's test."
The new course of study forces students to solve problems rather than just memorize information for exams.
"Force is the right word for it," Bill says. "Many students are very uncomfortable with the course initially because it asks them to speculate upon possible answers before they have all the facts."
Students are divided into groups of six or seven and given a case on paper -- such as a horse with a deformed limb or an incontinent cat. They start with only the most basic information about the animal, such as its physical appearance and the owner's description of its behavior.
The students then speculate what might be wrong with the animal and make a hypothesis. This is where the real, practical learning begins.
"The students not only have to apply what they're getting in their major science classes like physiology and anatomy, but they also have to figure out what they don't know and go find it," Bill says.
"These classes liven up a course load that some students find a bit dry during their first two years," Bill says. "It helps them understand how important the basic sciences are to becoming a good clinical veterinarian. Students are going to be much more attentive to a lecture on kidney function if their study case involves a kitten in kidney failure."
CONTACT: Bill, (765) 494-8636: e-mail, bill@vet.purdue.edu
Ken Scheeringa, acting state climatologist for Indiana, stationed at Purdue University, says that the last major El Niño 15 years ago caused memorable changes in our weather.
Early predictions by the National Weather Service say that this El Niño is even more severe than the 1982-83 episode.
"It appears that El Niño is roaring back, and this one is showing signs it could become more intense than the one in 1982-83," he says. "That year parts of the central United States had a Christmas day in the 60-degree range."
The effects of El Niño are always the most apparent near Christmas, and the name "El Niño" refers to the Christ child.
"What we're in now is the opposite of an El Niño," Scheeringa says. "In the Midwest we're feeling the influences of a weather pattern known as 'La Niña.' With this the ocean surface temperatures are cold, and since the end of last year and the beginning of this year we have been in a predominately cool weather pattern. That's why parts of the country have seen such cool temperatures this past winter and into the spring. That appears to be changing, perhaps in a very intense way."
According to Scheeringa, the El Niño weather pattern could bring unusually warm and dry weather to the Midwest, especially in the winter months.
El Niño weather patterns occur every few years, most recently during the winters of 1994-95 and 1987-88. The last major El Niño occurred during the winter of 1982-83. That winter, storms caused damage in California and the Gulf States resulting in an estimated 100 deaths and more than $2 billion damage.
Dayton Vincent, professor of atmospheric sciences at Purdue, says there is some disagreement among researchers about what causes El Niño, but there some characteristics that all weather scientists agree on.
Vincent says two events happen nearly simultaneously to create the weather pattern known as El Niño. "Water over the eastern Pacific, especially just south of the equator, becomes much warmer than normal during December and January," he says. "The second occurrence is that low-level winds from the region stretching from the western Pacific to east of the International Dateline become more westerly or, at least, less easterly than normal. This actually causes upwelling in the ocean circulation, and warmer waters come to the surface over the central Pacific to join those already over the eastern Pacific."
According to Vincent, wind changes in the lower atmosphere and in the Pacific Ocean cause a change in upper atmospheric circulation patterns. It's this upper atmospheric weather pattern, near jet stream levels, that ultimately influences weather in the United States, he says.
"It's well established that the southeastern part of the United States will see more cyclonic activity, and the northern Great Plains and south-central Canada will have more high pressure, so there are fewer storms and less rainfall," Vincent says. "In the Midwest, we lie in a zone that makes it difficult to tell if El Niño affects our weather. This spring we've had a lot of storms to the south while northern Minnesota and northern Michigan had better than normal weather. This could well be associated with the beginning El Niño conditions."
CONTACTS: Scheeringa, (765) 494-8105; e-mail, kenneth.l.scheeringa.1@purdue.edu; Vincent, (765) 494-3290; e-mail, dvincent@meteor.atms.purdue.edu
Compiled by Susan Gaidos, (765) 494-2081; e-mail, susan_gaidos@purdue.edu
Purdue News Service: (765) 494-2096; e-mail, purduenews@purdue.edu
Photo Caption
Color photo, electronic transmission, and Web and ftp download available. Photo ID:
Bill/Vetcourse
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