Steady exercise much better than stop-go cycles for weight control

William Atkins
Tuesday, 15 April 2008 09:05

Science - Health

A study by a researcher from the U.S. Lawrence Berkeley National Laboratory has shown that keeping weight off is easier when people exercise all year round, every year, and on a regular basis.


American researcher Paul Williams, of the Life Sciences Division at LBNL (Berkeley, California, U.S.A.), conducted the study whose purpose is stated in his paper’s abstract: “Although increases and decreases in physical activity are known to cause weight loss and weight gain, respectively, it is not known whether the magnitudes of these changes in weight are equal. Unequal (asymmetric) weight changes could contribute to overall weight gain or loss among individuals with seasonal or irregular activity.”

Williams studied data compiled from the National Runners’ Health Study. He studied 17,280 men and 5,970 women who decreased their running distance per week, and 4,632 men and 1,953 women who increased their running distance per week. Each group ran over a 7.7-year period.

He discovered that runners who decreased their exercise distance from five to zero miles (eight to zero kilometers) per week gained four times as much weight as those runners who decreased their weekly distance from 25 to 20 miles (40 to 32 kilometers).

Williams also found that people who took up running after an exercise layoff didn’t lose weight until their weekly mileage exceeded 20 miles in men, and 10 miles each week in women.

According to the study, gaining weight after stopping an exercise routine is very difficult to take off. It is much easier to never take breaks from exercise—that is, do not exercise only in certain seasons and do not exercise in irregular patterns.

Williams says that to maintain a regular weight, "Do Not Quit" with regards to exercise.

In the online article “Irregular Exercise May Add Pounds,” Science Today (University of California), William is quoted to have said, “The price to pay for quitting exercise is higher than expected, and this price may be an important factor in the obesity epidemic affecting Americans.”

Basically, Williams found that males that ran over twenty miles per week and females that ran over ten miles per week had less problems taking off weight if they stopped exercising for awhile.

However, men and women below those male-female levels, the weight gained from a stop in running took much more time to reverse. During these stoppages in running—when the exercise was less intense (involved less distance each week)—the ability to lose weight gained during non-exercise times was much more difficult to attain.

Williams states, "At lower mileages, there is asymmetric weight gain and loss from increasing and decreasing exercise, leading to an expected weight gain from an exercise hiatus. In other words, if you stop exercising, you don't get to resume where you left off if you want to lose weight."

Williams suggests that start-stop exercise habits are not conducive for losing weight and keeping it off.

The study conducted by Williams is titled "Asymmetric Weight Gain and Loss From Increasing and Decreasing Exercise." It is published in the February 2008 issue of the journal Medicine & Science in Sports and Exercise. The Williams article is also found at Medscape Today, under the same title.

A similar study was published in 2007 by Williams. Its results appear in the article “Vigorous Exercise Keeps People Thin with Age,” at Rerearch News (Berkeley Lab).