Bad news for men fighting middle-age spread: Weight gain may be inevitable, even among serious athletes.
In a study involving 4,769 male runners under the age of 50, Paul Williams of
the Ernest Orlando Lawrence Berkeley National Laboratory (Berkeley Lab)
investigated the question of whether vigorous exercise can prevent weight gain
with age. Williams found that in middle-aged men, waist-line expansion is
almost a force of nature. Those who exercise will be leaner than sedentary
individuals but even devoted runners will find it increasingly difficult to
The outlook for men over the age of 50 is similar, at least around the waist.
Examining a second set of 2,150 male runners (all over the age of 50), Williams
found that men over the age of 50 appear to gradually lose muscle mass and
weight as the years pass. Unfortunately, the runners' waist sizes generally did
not deflate with age.
Williams reports these findings in the May issue of the American Journal of
Clinical Nutrition. They are the latest results from the National
Runners' Health Study, ongoing research that is headed by the Berkeley Lab life
Aside from the sagging egos that are associated with bulging beltlines, there
are also serious health consequences.
Expanded waists usually are the result of increased abdominal fat. According to a large body of scientific evidence, this fat is linked to high cholesterol, high blood pressure, diabetes, and heart disease.
Williams says the current study was designed to explore the fundamental
question of whether middle-age weight gain is a basic physiological consequence
of aging or the result of declining activity levels.
The study showed that in 4,769 runners between the ages of 18 and 50, weight gain occurred at the same rate almost regardless of the number of miles run per week. Per decade, the average six-foot-tall man gained about 3.3 pounds and about 3/4 inches around the waist.
Over the years, this weight gain adds up. Among the under-30 age group of
runners in the study, 21 percent were moderately overweight; in the 45-49 age
group, 30 percent were overweight.
Says Williams, "Our data suggests that you can probably compensate for
middle-aged weight gain by becoming more active. By annually increasing weekly
running distance by about 1.4 miles, we estimate that the effects of exercise
should compensate for the expected weight gain during middle age. What this
means is that runners who average 10 miles per week at age 30 should increase
their weekly running distance to 24 miles by age 40 if they plan to still fit
into the tuxedo they bought a decade earlier."
The findings in this study reveal a contradiction inherent in the current
national health policy.
The widely following guidelines for recommended weight -- the Department of
Agriculture's 1995 Dietary Guidelines for Americans -- set the same overweight
standards for young and old alike. Likewise, the federal guidelines for
physical activity are the same, calling for equal amounts of exercise for both
younger and older adults. Both the Surgeon General and the Centers for Disease
Control and Prevention recommend 30 minutes of moderate physical activity for
everybody on most days of the week.
Williams says the government's recommendations for physical activity and for
weight are in conflict.
"If the federal weight standard is going to make no distinction for age, then
we believe that physical activity guidelines should recommend substantial
increases in activity over time. The alternative," says Williams, "is to adopt
a weight standard that accommodates the normal consequences of aging. Earlier
versions of the federal weight guidelines allowed people to gain weight as they
Without doubt, physical inactivity and dietary choices play a major role in
the prevalence of obesity in this country. However, says Williams, the results
of this study indicate that physiological changes that occur as we age also
lead to weight gain. The underlying cause of these physiological changes
remains an enigma. Some suggest declining testosterone or "male menopause" as
a cause. Several genes recently have been identified that may regulate weight.
Williams suggests that runners may be ideal subjects for a study to reveal the
biological basis of middle-age weight gain since running appears to reduce the
influences of inheritance and diet, but not middle age.
Women may wonder what this study portends for them. Currently, WIlliams is
examining the pattern of weight gain in women runners, a pattern which could be
fundamentally different from that observed in men. Prior to menopause, women
tend to gain fat in their hips and thighs rather than in their waists, and they
may be particularly vulnerable to weight retention after pregnancy.
Berkeley Lab conducts unclassified scientific research for the U.S. Department
of Energy. It is located in Berkeley, California and is managed by the
University of California.