Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Weekends slow weight loss, researchers find

03.07.2008
Saturday can be the worst enemy for our waistlines, according to researchers at Washington University School of Medicine in St. Louis.

They found that study subjects on strict diet and exercise programs tend to lose weight more slowly than expected because they eat more on weekends than during the week. The investigators report their findings in the advance online publication of the journal Obesity.

Past research had confirmed that people tend to gain weight during the holidays, particularly between Thanksgiving and New Year's, but this is the first study to carefully monitor daily body weight, calorie intake and calorie expenditure for several weeks throughout a year, and to demonstrate that increased caloric intake isn't just a problem during the holidays. It also happens on most weekends.

"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," says first author Susan B. Racette, Ph.D., assistant professor of physical therapy and of medicine. "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 followed 48 adults between the ages of 50 and 60 who took part in the CALERIE (Comprehensive Assessment of Long-term Effects of Reducing Intake of Energy) study. Body mass index (BMI) ranked subjects as overweight or healthy weight when the study began. None were classified as obese.

Following earlier studies demonstrating that mice and rats live longer, healthier lives when on a calorie restricted diet, the CALERIE study is designed to determine whether taking in fewer calories over a long time period will slow down or reverse some of the common markers of aging and disease.

"But rats don't have weekends the way people do," Racette says. "On weekends, human lifestyle patterns can be very different. People have social events, parties to attend, and if they have children who play sports, they might be at fields all day long, relying on concession stands for food."

Study participants were divided into three groups: the first lowered their daily calorie intake by 20 percent, a second increased daily physical activity by 20 percent, and a third, control group did not change diet or activity levels. All three groups were monitored for one year. They kept food diaries, tracked exercise with accelerometers and were weighed regularly. Racette says people in the study didn't always realize they were eating significantly more food on weekends.

"It was surprising how consistent the findings were," she says. "We also were surprised by the dramatic way in which weekends continued to slow weight loss throughout the course of the study."

Before the interventions began, the researchers established "baselines" for each study participant's exercise and eating habits. This pre-intervention data determined that participants consumed the most calories on Saturdays. An average of 36 percent of their total calories came from fat on Saturdays, but less than 35 percent came from fat during the rest of the week. The typical weekend weight gain before the diet and exercise interventions began would have led to an average increase of 9 pounds a year.

When study participants were asked either to cut calories by 20 percent or to increase activity by a like amount, the pattern remained the same. Those in the calorie restriction group took in more energy on Saturday. Those in the exercise group ate more on both Saturday and Sunday. As a result, people in the calorie restriction group stopped losing weight on weekends, and those in the exercise group actually gained weight on weekends.

"People on diets often don't lose as much weight as we would expect, and this finding helps to explain why," she says.

As the researchers move into the second phase of the CALERIE study, looking at more subjects over a longer period of time, they now recommend that participants weigh themselves daily in order to be more aware of their patterns of weight loss and weight gain, particularly on weekends. For those not in a research study, she recommends moderation and careful planning to avoid weekend pitfalls.

"Planning ahead can't be emphasized enough," Racette says. She recommends packing healthy food if you're running errands, eating a little something so you aren't starving when you arrive at a party, even packing a light lunch before going to the kids' ballgames so that you have a choice other than junk food at a concession stand.

"In addition, she says, "paying closer attention to portion sizes can enable a person to enjoy the weekend without sabotaging weight-control efforts."

Racette SB, Weiss EP, Schechtman KB, Steger-May K, Villareal DT, Obert KA, Holloszy JO, and the Washington University School of Medicine CALERIE Team. Influence of weekend lifestyle patterns on body weight. Obesity, advance online publication doi: 10.1038/oby.2008.320

This study was supported by the National Institutes of Health.

Washington University School of Medicine's 2,100 employed and volunteer faculty physicians also are the medical staff of Barnes-Jewish and St. Louis Children's Hospitals. The School of Medicine is one of the leading medical research, teaching, and patient care institutions in the nation, currently ranked third in the nation by U.S. News & World Report. Through its affiliations with Barnes-Jewish and St. Louis Children's Hospitals, the School of Medicine is linked to BJC HealthCare.

Jim Dryden | EurekAlert!
Further information:
http://www.wustl.edu

More articles from Studies and Analyses:

nachricht Rutgers-led innovation could spur faster, cheaper, nano-based manufacturing
14.02.2018 | Rutgers University

nachricht New study from the University of Halle: How climate change alters plant growth
12.01.2018 | Martin-Luther-Universität Halle-Wittenberg

All articles from Studies and Analyses >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: Attoseconds break into atomic interior

A newly developed laser technology has enabled physicists in the Laboratory for Attosecond Physics (jointly run by LMU Munich and the Max Planck Institute of Quantum Optics) to generate attosecond bursts of high-energy photons of unprecedented intensity. This has made it possible to observe the interaction of multiple photons in a single such pulse with electrons in the inner orbital shell of an atom.

In order to observe the ultrafast electron motion in the inner shells of atoms with short light pulses, the pulses must not only be ultrashort, but very...

Im Focus: Good vibrations feel the force

A group of researchers led by Andrea Cavalleri at the Max Planck Institute for Structure and Dynamics of Matter (MPSD) in Hamburg has demonstrated a new method enabling precise measurements of the interatomic forces that hold crystalline solids together. The paper Probing the Interatomic Potential of Solids by Strong-Field Nonlinear Phononics, published online in Nature, explains how a terahertz-frequency laser pulse can drive very large deformations of the crystal.

By measuring the highly unusual atomic trajectories under extreme electromagnetic transients, the MPSD group could reconstruct how rigid the atomic bonds are...

Im Focus: Developing reliable quantum computers

International research team makes important step on the path to solving certification problems

Quantum computers may one day solve algorithmic problems which even the biggest supercomputers today can’t manage. But how do you test a quantum computer to...

Im Focus: In best circles: First integrated circuit from self-assembled polymer

For the first time, a team of researchers at the Max-Planck Institute (MPI) for Polymer Research in Mainz, Germany, has succeeded in making an integrated circuit (IC) from just a monolayer of a semiconducting polymer via a bottom-up, self-assembly approach.

In the self-assembly process, the semiconducting polymer arranges itself into an ordered monolayer in a transistor. The transistors are binary switches used...

Im Focus: Demonstration of a single molecule piezoelectric effect

Breakthrough provides a new concept of the design of molecular motors, sensors and electricity generators at nanoscale

Researchers from the Institute of Organic Chemistry and Biochemistry of the CAS (IOCB Prague), Institute of Physics of the CAS (IP CAS) and Palacký University...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

VideoLinks
Industry & Economy
Event News

2nd International Conference on High Temperature Shape Memory Alloys (HTSMAs)

15.02.2018 | Event News

Aachen DC Grid Summit 2018

13.02.2018 | Event News

How Global Climate Policy Can Learn from the Energy Transition

12.02.2018 | Event News

 
Latest News

A Keen Sense for Molecules

23.02.2018 | Physics and Astronomy

“Laser Technology Live” at the AKL’18 International Laser Technology Congress in Aachen

23.02.2018 | Trade Fair News

Newly designed molecule binds nitrogen

23.02.2018 | Life Sciences

VideoLinks
Science & Research
Overview of more VideoLinks >>>