Taking a vacation — even if it involves a lot of walking — is likely to lead to a small but significant weight gain that will persist even after you return back home, according to a study published earlier this month.
Researchers found that people who go on vacation for one to three weeks gain an average of a third of a pound while they’re away — added weight that tends to remain on their bodies at least six weeks after they return.
The extra weight may sound inconsequential, but it probably contributes, say the study’s authors, to the slow but steady gain in weight — an average of 0.9 to 2.2 pounds per year — that so many Americans accumulate over their lifetime, starting in early adulthood.
As the study’s authors also point out, 70 percent of American adults are either overweight or obese.
For the study, Cooper recruited 122 adults (43 men and 79 women) aged 18 to 65 who were about to take a short vacation (seven to 21 days) in a location away from home. Participants met with researchers three times: right before the vacation, right afterward, and then six weeks later. Various measurements, including weight, body mass (BMI) and waist-to-hip ratio, were taken at each meeting. Blood pressure was also measured, and the participants answered questions about health-related habits, such as exercise.
Forty-six of the participants (37.7 percent) were overweight at the start of the study, while 19 (15.6 percent) were obese. The average BMI of the participants before they went on vacation was 25.8, which falls into the “overweight” category (although not by much).
When the participants returned from their vacations, 75 of them (61 percent) had gained weight — an average of 0.32 pounds each. Six weeks after the vacation, the total average weight gain had increased a bit more, to .41 pounds.
Those people who had been away from home the longest tended to have put on the most weight.
Importantly, at their six-week post-vacation meeting with the researchers, only 39 of the 75 participants who had gained weight said they were trying to lose it.
“This highlights the importance of ‘creeping obesity’ and how it can be problematic for individuals to prevent weight gain,” writes Cooper. “The amount of weight gain that occurred on the vacations was small; possibly too small for most participants to feel like it was necessary to try to lose the weight they had gained. Yet the fact that this weight gain persisted indicates that the vacation weight gain could contribute greatly to yearly weight gain.”
“In fact,” she adds, “one vacation alone could theoretically make up all of a person’s yearly weight gain.”
Cooper also points out that, on a daily basis, the vacation-related added weight observed in this study is more than twice the average amount that previous research has found people gain over the two- to three-month annual holiday season of pre-Thanksgiving to post-New Year’s Day.
What might have caused people to gain weight while on holiday?
Interestingly, the weight gain didn’t seem to be associated with a decrease in physical activity. The study’s participants actually tended to report increases in their total daily physical activity during their vacations, particularly an increase in the time they spent walking.
That finding suggests that the weight gain came primarily from eating more, not from exercising less, says Cooper. Unfortunately, the study collected only limited data on the vacationers’ dietary habits, although 107 of the participants (88 percent) did acknowledge consuming more food while they were away.
They also reported a huge increase in their alcohol consumption — from an average of eight drinks per week before they left on their trips to an average of 16 drinks per weeks while vacationing.
Given the amount of calories in alcohol, those drinks could alone explain up to 30 percent of the weight gain observed in the study, says Cooper.
The study has some important limitations. It included a relatively small number of participants, for example, and had no control group. It also followed people for only six weeks, a time frame that may not have been long enough to capture the participants shedding the pounds they had gained.
Still, writes Cooper, “it is important for adults to understand how small weight gain on a vacation can be meaningful, and that this weight gain should be lost to help prevent yearly weight gain and creeping obesity.”
One final finding from the study: Cooper reports that the participants tended to experience a “significant” reduction in their systolic blood pressure and in their self-perceptions of stress while on vacation — and that both these benefits were still apparent six weeks after the vacation had ended.
But, she warns, “whether or not these positive changes in [blood pressure] and stress can overcome the negative health implications of gaining weight on vacation are yet to be determined.”
FMI:You’ll find an abstract of the study on the Physiology & Behavior website. The full study is behind a paywall. Physiology & Behavior is the official journal of the International Behavioral Neuroscience Society.