Stuffing, cookies and mashed potatoes aren’t the only waist-thickening foods to look out for during the holidays — sugar-laden libations like apple cider, pumpkin spice lattes, mulled wine and hot cocoa are the sneakiest suspects when it comes to weight gain. New research from the Harvard School of Public Health shows that people with a genetic predisposition for putting on pounds are also at a higher risk for weight gain from downing sugary drinks.

The study, published in The New England Journal of Medicine, looked at the genetic predisposition for obesity of more than 33,000 people and gave them a score from zero to 64 indicating their risk. Those who had less than one sugary beverage a month had a 35 percent higher risk for every 10 points on the scale. Those who gulped one or more sugary drinks daily had a 235 percent increase in risk.

Similar studies with children and teens found that they too grew a little thicker after downing sweetened drinks. What’s troubling is that many seemingly healthy drinks marketed to kids, like sweetened fruit juice and sports drinks, often have almost as much sugar as sodas. Drinking just one sugar-laden refreshment a day boosts a kid’s chances of becoming obese by 60 percent, so it’s up to parents to encourage hydration with good old fashioned water instead and limiting sweetened stuff to special occasions.

The good news is that Americans are consuming fewer sweetened drinks, and calorie intake from refined refreshments decreased more than 20 percent in nine years. But we still have a ways to go. Keeping liquid calories in check can keep your waistline in line, so aim to cut back on sugary drinks. Try tea, lemon-zested water or sparkling water instead if plain old tap is too boring for you.