Weekends Can Be Diet Busters - Changes in Lifestyle Patterns on Weekends Sabotage Weight Loss Efforts

Weekends aren't made for weight loss.

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 activity level.
• 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 pounds.

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, too.