We at Marie Claire are not in the business of telling you what to do—that would be futile, because you're going to do what you want anyway. No, we are here to examine, through our own experiences and research, possible, better methods of Doing Things, because perpetual self-improvement is the goal. Therefore, you could either align with tradition and resign yourself to stretchy waistbands and self-hatred from now until the first two weeks of January, after which apathy will set in permanently. Or you could try this one zero-effort suggestion and feel the same level of slow-burning self-loathing you feel now. The choice is yours!
Karl Lagerfeld once said sweatpants are a sign of defeat, and in this (not this), I know he is right. Loose clothes allow for mistakes; snug clothes encourage control. Which do we turn to in the safety of our homes? For comfort in the uncertainty of the airport? Technically, the holidays are meant to be a time of coziness and celebration, but a) loungewear tends to be sloppy, and b) as someone who only deals in extremes, elastic allows for excess, which allows me to consume seven frosted Santa Clauses, two snowmen with chocolate-chip buttons, and a pan of stuffing, even though "I'm technically not gluten-intolerant, but it makes me puffy."
"Loose clothes allow for mistakes; snug clothes encourage control."
The universal lesson, then, to be learnt from my personally destructive give-an-inch-take-a-mile-ness? NO STRETCHY PANTS. Even more reasonable people would do well to continue wearing their real-life jeans—yes, the ones that are snug around the hips and bum like those rubbery swing seats out of which adult men keep needing to be sawed. Because when you are buttoned into your trousers more tightly than Elon Musk will be in his spacesuit when he finally escapes Earth for more cosmic pastures, that is a built-in safety measure—against mashed potatoes that are more Cantal than tuber, against your own weakness, against regret. Enjoying oneself does not mean forgetting oneself.
Your perfectly appropriate response to all this could be "Jeez. Live a little." But when you've never done anything just "a little," this has to be the way.