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A research team has demonstrated that intellectual work induces a substantial increase in appetite and calorie intake. This discovery could help to explain, in part, the current obesity epidemic.
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The team measured the spontaneous food intake of 14 students after each of three tasks: relaxing in a sitting position, reading and summarizing a text, and completing a series of memory, attention, and vigilance tests on the computer.
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Each session of intellectual work required only three calories more than the rest period. However, despite the low energy cost of mental work, the students spontaneously consumed 203 more calories after summarizing a text and 253 more calories after the computer tests than they did after relaxing.
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Blood samples taken before, during, and after each session revealed that intellectual work caused bigger fluctuations in glucose and insulin levels — two critical components in the body’s regulatory and energy machinery — than rest periods.
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Jean-Philippe Chaput, the lead author of the study, said that mental work “destabilizes” the levels of insulin and glucose, thus stimulating the appetite, apparently in response to a need to restore the body’s energy balance.

Is a person’s weight really a reliable indicator of overall health?

Some medical research is showing that it isn’t. Last week a report in The Archives of Internal Medicine compared weight and cardiovascular risk factors among a representative sample of more than 5,400 adults. Half of the overweight people and one-third of obese people in the study were “metabolically healthy.” That means that many overweight and obese adults may have healthy levels of “good” cholesterol, blood pressure, and blood glucose.

At the same time, about one out of four slim people in the study actually had at least two cardiovascular risk factors typically associated with obesity.

Being overweight or obese is definitely linked with numerous health problems. Nonetheless, researchers found the proportion of overweight and obese people who are metabolically healthy surprising.

Several studies have shown that fitness, as determined by how a person performs on a treadmill, is a far better indicator of health than body mass index. Some research has indicated that people who are fat but can still keep up on treadmill tests have much lower heart risk than people who are slim and unfit.

The Corn Refiners Association is launching a major advertising and public relations campaign designed to rehabilitate the reputation of high fructose corn syrup (HFCS). HFCS has been linked by many scientists to the nation’s obesity epidemic.

The group is spending $20 million to $30 million on the campaign, including running full-page ads in more than a dozen major newspapers, claiming that the product is no worse for you than sugar. The ad, which features a stalk of corn, carries the headline: ‘And Now a Little Food for Thought.’

The Corn Refiners Association “has been trying to counter the bad publicity around HFCS since 2004,” but concluded it “could no longer afford to rely on simple grass-roots marketing tactics such as talking with nutritionists and doctors.”

Meanwhile, in June a nearly $5 billion merger of Corn Products International and Bunge Ltd. signaled that corn manufacturers mean business. Revenues were expected to increase 29 percent in 2008 to reach $4 billion.