
Dieters' Responses Slowed in Study By Marcia
Wood April 9, 1997Women who cut calories to lose weight
may inadvertently slow their reaction times, an effect that can continue for
weeks after the women have stopped dieting. Thats the finding from a study by scientists with
USDAs Agricultural Research Service
and the Institute of Food Research of the
British Biotechnology Sciences Research Council. The scientists report
their findings today (April 9) in New Orleans at a meeting of the
Federation of American Societies for
Experimental Biology. Reaction time lengthened by 11 percent in women volunteers who went on a
reducing diet directed by researchers from the ARS
Western Human Nutrition Research
Center in San Francisco. The volunteers reaction times continued to
slow for 3 weeks after they had stopped dieting and started eating enough to
maintain their new, lower weights. Researchers want to determine whether this slowdown lowers dieters'
alertness--and thus increases their risk of accidents--or whether the even
longer-term regimens sometimes needed to achieve healthful weights might
increase such risks. Fourteen women, age 25 to 42, participated in the study. Overweight but
otherwise healthy, the volunteers lost an average of 27 pounds. During the
15-week reducing-diet-phase of the 21-week study, the women ate only half of
the number of calories needed to maintain their beginning weight. The study was
longer than other experiments on dieting and mental performance reported during
the past five years. At five intervals during the experiment, scientists measured reaction times
by determining how long it took the volunteers to strike the space bar on a
computer keyboard when a white star appeared on their screen. This "simple
reaction time" does not require thinking through options and making a
choice. Further study of dieting's effects on reaction time could lead to new
understanding of how the body uses calories and nutrients for thought and
action. That new information could be used by healthcare professionals to
improve diet and exercise regimens for the estimated one-half of all American
women who, at any given time, are on a reducing diet. Scientific contact: Mary J. Kretsch, USDA-ARS Western Human Nutrition Research
Center, San Francisco, Calif., phone (415) 556-6225,
[email protected]. U.S. Department of Agriculture | |