Researchers in St. Louis say that Saturdays and Sundays often pose as big a
threat to our waistlines as holidays. Many people tend to pack on a few extra
pounds during the holidays -- particularly the period from Thanksgiving to New
Year's -- because they eat more and exercise less.
Similar lifestyle changes on the weekends also lead to weight gain , slower weight
loss, and problems maintaining significant weight loss. Susan B. Racette, PhD,
assistant professor of physical therapy and medicine at the Washington
University School of Medicine in St. Louis, and colleagues have found that
older adults on strict diet and exercise programs tend to take in
more calories on the weekends than during the week.
"We thought weekends would present a problem for some people attempting
to lose weight, but the consistency of our finding before and during the
interventions was surprising," Racette says in a news release.
"Subjects in the diet group lost weight during the week, but over the
weekend, they stopped losing weight because they were eating more."
Racette's team wanted to see if changes in diet or activity patterns during
the weekends would help or hinder weight loss. Their study involved 48 older
adults, aged 50-60, who took part in the CALERIE (Comprehensive Assessment of
Long-term Effects of Reducing Intake of Energy) study. CALERIE is a
government-funded study to investigate whether two years of calorie restriction
can slow down the aging process and reduce the risk of certain diseases.
The participants had their exercise and eating habits and body mass index (BMI) charted
at the start of the study. No one was considered obese . Most participants took
in the most calories on Saturdays.
Researchers divided the participants into three groups:
- Group 1 took in 20% fewer calories each day but didn't change their
- Group 2 increased their daily exercise regimen but didn't change their
diet, to have a comparable energy deficit as Group 1.
- Group 3 did not change their diet or activity level.
Researchers followed the participants for a year. Food diaries, regular
weigh-ins, and exercise accelerometers helped keep close tabs on their
progress. At the beginning of the trial, about 36% of each person's total
calories came from fat eaten on Saturdays, but less than 35% was due to fatty
foods eaten during the rest of the week. The typical weekend weight gain at the
beginning of the study would have led to an average increase of nearly 9 pounds
a year, according to researchers.
However, even after the diet and exercise interventions, researchers found
the pattern remained the same. Those in the calorie-restriction group stopped
losing weight on weekends. Those who exercised more ate more on Saturdays, and
actually gained weight on weekends. Many of the study participants didn't
realize that the weekends were diet busters.
"It was surprising how consistent the findings were," added Racette.
"We also were surprised by the dramatic way in which weekends continued to
slow weight loss throughout the course of the study."
The findings, which appear in the advance online publication of the journal
Obesity, help explain the relatively slow rates of weight loss observed
in many studies and why so many people have trouble keeping off lost
Careful planning can help make sure that weekends do not sabotage your
weight-control efforts. Packing healthy foods when you're on the go can help
you avoid concession-stand temptations. Controlling portion size is important,
By Kelli Stacy
Reviewed by Louise Chang
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