Students, Faculty Study the Science of Gaining Weight
It may not always be as simple as it sounds, but, in general,
stress, sleep deprivation and estrogen loss can make you gain weight.
That’s according to Gwyneth Beagley, whose recent research with
students Melissa Barclay ’08 and Kathryn Krauss ’09 analyzed how
stress, sleep and aging affect appetite and weight gain.
Beagley, professor of psychology at Alma College, is writing a book on
the physiology of eating, hunger signaling from the body to the brain,
and the interactions among important hormones like leptin (which
regulates appetite), ghrelin (which prompts hunger) and insulin.
Gwyneth Beagley and students study the physiology of eating.
“Levels of leptin and ghrelin influence whether you are eating
or not,” says Beagley. “In research studies, mice bred not to produce
leptin will eat and gain significant weight. Add leptin, they go back
to regular size. At one time, scientists thought leptin was a cure for
obesity, but it’s not.
“Obesity may result from a problem with the receptors in the brain that
receive the hormonal signals from the body,” she says. “The older you
get, there is a loss of receptor sensitivity. So one can say age makes
you gain weight.”
Regarding Stress:
When someone is stressed, the brain sends a signal to the hypothalamus,
the part of the brain that links the nervous system to the endocrine
system via the pituitary gland, which results in the release of body
chemicals such as adrenaline and steroids to deal with the stress, says
Beagley. If the stress is sudden and threatening, the adrenaline
provides the energy to run away or respond physically. The steroids
deliver sugar to the muscles to help the heart beat faster in response
to the sudden stress.
However, stress related to on-going worries also produces adrenaline and steroids that cause a different affect.
“Steroids are not great for dealing with on-going stress,” says
Beagley. “They make you hungry by interfering with leptin. Steroids
also store food around your middle.”
Regarding Sleep Deprivation:
Studies show that people in general are getting less and less sleep —
from an average of eight to nine hours a night 50 years ago to an
average of five to six hours now. In addition, multiple studies
indicate an increase in obesity. In response, Beagley and Barclay
conducted research on the relationship of sleep deprivation and obesity.
Using rats as her subjects, Barclay placed groupings of rats in
different environments — some in large colony rooms and others in small
spaces, some subjected to loud music to inhibit their sleep, and some
with Oreo cookies. Research results indicated that the sleep-deprived
rats with access to lots of cookies were the fattest — more so than
rats that weren’t sleep deprived.
Barclay’s study supported another (non-Alma-related) study with healthy
college students who were limited to four hours of sleep per night.
Researchers found that the sleep-deprived students tended to eat more.
Their calorie intake increased while their leptin levels decreased.
Regarding Estrogen Loss:
Krauss and Beagley also worked with female rats in a study on estrogen
loss. Estrogen removal causes weight gain and in increase in appetite,
says Beagley. In her study, Krauss removed estrogen in some rats and
put some rats on high-fat diets. Among the various groups, the fattest
rats were those that had no estrogen and high-fat diets.
Research by Beagley and her students continue as she works on her book manuscript.
“We’re looking at the histology of brain tissue to see if behavioral
changes are reflected with brain morphology changes,” says Beagley.
Posted: Thu, October 9th, 2008 at 3:44PM
