Do we really gain as much weight during the holiday season from Thanksgiving to New Year's as we think we do? When surveyed, most people have the perception that they gain a great deal of weight during this time.
Some years ago Drs. Jack and Susan Yanovski and their colleagues at the National Institutes of Health conducted a well-designed study to investigate just that question. Their subjects were mostly NIH employees, with a range of occupations (from those who worked in maintenance to professionals engaged in research) and with both ethnic and racial diversity as well. Their sample of almost two hundred men and women ranged in age from 19 to 82. Among other measurements taken, they measured their subjects' weights on four different occasions throughout the year. They masked the real purpose of the study by presenting it as one interested in seasonal changes in vital signs lest their subjects be tempted to change their eating patterns in response.
What they found is that people thought they were gaining four times as much as they actually had gained! Fewer than 10% of their sample actually gained over five pounds. Most had gained less than a pound. But those who were overweight or obese initially were the ones most likely to gain those five or more pounds, so their conclusion was that the holiday season "may present special risks" for those who do already have a weight problem. Furthermore, the researchers found that even though the average weight gain was fairly minimal, people tended to gain the most weight for the year around this time and not lose this holiday weight once the holidays were over. The result is a "cumulative" gain, or what we might call a kind of "holiday creep." In other words, even though for many, the actual weight gain this time of year is trivial, it may not be trivial over time. In general, as we age, if not watching carefully, we tend to gain one to two pounds a year as our metabolism slows, and particularly, if we lose muscle. So the holiday season may be a crucial time responsible in part for this cumulative gain year after year.
There are many reasons people tend toward weight gain during the holidays, including overeating as a reaction to the stress of being with family or even the stress involved in all the holiday preparations. Others develop a "What the hell?" attitude such that they decide to forgo their usual diets during this time. Furthermore, some people are sensitive to shorter days and have a seasonal affective disorder such that they may become depressed and tend to overeat in response. Sometimes, people are less physically active in the winter holiday months so they are less likely to burn off the excess calories. These are the "hibernators." Still others may find the tempting array of foods prepared specially for the holidays irresistible. The more variety and the more palatable the food choices given to people (or animals, for that matter), as for example, with a buffet style of eating, the more likely they will over-consume.
"Diet consistency," that is, not changing your eating style for holidays or weekends, has been shown to be an important factor to keep weight off in those who have lost weight and maintained that loss. This is one of the results of the National Weight Control Registry, a study begun by Rena Wing and James Hill in the early 1990s, of a non-random group of dieters who have lost at least 30 pounds and kept the weight off for more than a year. (Most in the study have lost much more weight and kept it off for a much longer time.) Another finding from this study is that successful dieters are accountable: they weigh themselves frequently (and often daily) and watch what they eat, often by counting calories or even keeping a food diary. People, even those who maintain their weight, are often notoriously inaccurate in remembering or tallying how many calories they eat in a day. This is called the "eye-mouth gap"--the difference between how much people think they are eating and how much they are actually eating. Obese people sometimes report only one-half to two-thirds of what they are eating, and even thin people may report only 80%. Of course, it is quite difficult to remember everything we eat. As food author Michael Pollan, in his book, In Defense of Food, has said, "I'm not sure Marcel Proust himself could recall his dietary intake ... with the sort of precision demanded."
So what else should one do to prevent "holiday creep?" Well, Cora Craig, writing a few years ago in the Canadian Medical Association Journal, suggested that Santa Claus,though himself fairly obese, remains jolly and tries to keep himself as healthy as possible by his physically active lifestyle, that is, by jumping from rooftop to rooftop. For the rest of us, she suggests lots of "dancing and prancing!"