Weekends can slow down healthy eating plans and weight loss, according to a study reported in the journal Obesity.
Researchers found that participants on strict diet and exercise programs tend to lose weight more slowly than expected because they eat more on weekends than during the week.
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.
The study also demonstrates that increased caloric intake is not 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 author Susan B. Racette, Ph.D., at Washington University School of Medicine in St. Louis.
"Subjects in the diet group lost weight during the week, but over the weekend, they stopped losing weight because they were eating more," says Dr. Racette.
Dr. 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.
Earlier studies demonstrated 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," says Dr. Racette. "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.
Dr. Racette says people in the study did not 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 nine 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," Dr. Racette says.
She recommends packing healthy food if you are running errands, eating a little something so you are not 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."
Always consult your physician for more information.
While losing weight is difficult for many people, it is even more challenging to keep weight off.
One-third to two-thirds of those who lose a large amount of weight regain it two to three years later.
One theory about regaining lost weight is that people who decrease their caloric intake to lose weight experience a drop in their metabolic rate, making it increasingly difficult to lose weight over a period of months.
A lower metabolic rate may also make it easier to regain weight after a more normal diet is resumed. For these reasons, extremely low calorie diets and rapid weight loss are discouraged.
Losing no more than one to two pounds per week is recommended. Incorporating long-term lifestyle changes will increase the chance of successful long-term weight loss.
Weight loss to a healthy weight for a person’s height can promote health benefits such as lower cholesterol and blood sugar levels, lower blood pressure, less stress on bones and joints, and less work for the heart.
Thus, it is vital to maintain weight loss to obtain health benefits over a lifetime.
Keeping extra weight off requires effort and commitment, just as losing weight does. Weight loss goals are reached by changes in diet, eating habits, exercise, and, in extreme circumstances, surgery.
The strategies that encourage weight loss also play an important role in maintenance.
Support systems used effectively during weight loss can contribute to weight maintenance.
A study conducted by the National Weight Control Registry found people who lost weight and continued bi-monthly support group meetings for one year maintained their full weight loss.
Study participants who did not attend support group meetings regained almost half of the weight.
Physical activity plays a vital role in maintaining weight loss. Studies show that even exercise that is not rigorous, such as walking and using stairs, has a positive effect. Activity that uses 1,500 to 2,000 calories per week is recommended for maintaining weight loss.
Diet and exercise are vital strategies for losing and maintaining weight. A study by the National Weight Control Registry found that nearly all of 784 study participants who had lost at least 30 pounds, and had maintained that loss for one year or longer, used diet and exercise to not only lose the weight, but also to maintain the weight loss.
Once the desired weight has been reached, the gradual addition of about 200 calories of healthy, low-fat food to daily intake may be attempted for one week to see if weight loss continues.
If weight loss does continue, additional calories of healthy foods may be added to the daily diet until the right balance of calories to maintain the desired weight has been determined.
It may take some time and record keeping to determine how adjusting food intake and exercise levels affect weight. Continuing to use behavioral strategies can help maintain weight.
Be aware of eating as a response to stress and use exercise, activity, or meditation to cope instead of eating.
A return to old habits does not mean failure. Paying renewed attention to dietary choices and exercise can help sustain behaviors that maintain weight loss. Identifying situations such as negative moods and interpersonal difficulties and incorporating alternative methods of coping with such situations rather than eating can prevent relapses to old habits.
Always consult your physician for more information.
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