As Thanksgiving has just passed, and the holiday season is upon us, it is often known to be a season full of yummy food…and pounds packed on.  But how entirely truthful is this theory? Is there scientific evidence that can prove or disprove holiday weight gain?

Well, according to a study from the New England Journal of Medicine, it found that people’s perceived weight gain varied between 0 and 6.7 pounds with an average of 3.5, but their actual weight gain was just under 1 pound.  The study measured body weight in a convenience sample of 195 adults. The subjects were weighed four times at intervals of six to eight weeks, so that weight change was determined for three periods: preholiday (from late September or early October to mid-November), holiday (from mid-November to early or mid-January), and postholiday (from early or mid-January to late February or early March). A final measurement of body weight was obtained in 165 subjects the following September or October.

In addition, a study from Texas Tech University conducted by Assistant Professor Jamie Cooper, followed 48 men and 100 women between the ages of 18 and 65 for the six weeks between Thanksgiving and New Year’s Day. At the beginning and end of the study, researchers measured the subjects’ weights and body fa
t percentages. On average, the volunteers gained one and a half pounds (men about two pounds each, and about a pound for the women), far less than the 7 to 10 pounds often cited this time of year.

As I grew skeptical that the surplus of holiday food at family dinners alone created the extra pounds, I found some possible confounding variables that could lead to weight gain, even if it is a marginal gain.

So why do we think we’re gaining more weight than we do? One of the reasons you may feel like you’ve packed on more weight than you have is because many holiday foods trigger bloating and water retention. For example, any time you eat more carbs than usual, you store the leftovers as glycogen, the “piggy bank” reserve of carbohydrate that gets socked away in your muscle tissue.  Holding onto more glycogen than you usually do can cause you to feel sluggish, and make your jeans tighter, but as soon as you go back to your usual eating pattern, you’ll shed the surplus. Also, high sodium foods, like breads and baked goods, which don’t seem “salty” but are sodium-rich, will cause your body to hang onto excess fluid. While neither of these body shifts are fat weight, they can create a bloated look, and make you feel heavy.

Another reason, which we have heard countless times from Andrew’s lectures, is that our intuition is lousy.  We see a buffet table of food and think “wow I’m going to eat so much and get so fat.”  When in reality, we are generally eating the amount of food that we can normally handle, despite how big our eyes get.  Turns out I wasn’t alone in thinking this.

According to Paleo Leap, a diet lifestyle site, one factor is social pressure and the judgment that others give you based on what/how much you eat.  This study shows how people eating with a group tend to match their intake to the group “average.” So even if nobody’s pressuring you about it, there’s a constant psychological cue to overeat at every meal.  Another factor is stress; holiday commitments can be stressful and lead to comfort eating; and nobody comfort-eats celery sticks. In addition, cortisol (the stress hormone) also promotes weight gain, especially the dreaded “belly fat.”  Then there’s broken routines. When you’re traveling it means you spend a lot of time sitting, you get thrown off your regular exercise routine, and you aren’t always in control of your food.  Lastly, there’s emotional strings attached to holiday eating habits. If Grandma made it just for you, it gets a lot harder to refuse, especially if you have fond memories of eating it in years past.

Although I agree with the studies arguing there is not a significant weight gain during the holiday, I was still skeptical on them saying there is no real weight gain at all.  It has me wondering if for some people there is still more than a marginal gain. I propose a further study that looks at body types, preexisting conditions, gender, age, and lifestyle.  Furthermore, weight gain doesn’t equal physical condition so we would need to know other indicators of fitness AND what their normal baseline of diet is.

Science, as it turns out, has a lot more to say about holiday weight gain than “everything in moderation.” By knowing what the research actually says, it can help you go into the holiday party season feeling prepared and in charge.  In conclusion, the average holiday weight gain is less than commonly asserted. So in reality, the “holiday weight gain fear” is nothing to panic over: it’s nice to avoid it, but if you can’t, it’s not a catastrophe.  Remember that the holiday season only comes once a year and you have your whole life to worry about your eating habits!