There are certain shows — Survivor specifically comes to mind, as does any season of 24 — that are structured in such a way that if you miss the first episode, there's really no point in watching the rest of the season. Better to wait until the inevitable next season (in Survivor's case) or until the DVDs come out (24 is a perfect lazy/hungover weekend special) than stumble along always feeling behind. But then there are certain shows where, viewer beware, no matter how far into the season you accidentally tune in, you will be hooked and forced to watch the rest of the run. One such show is The Biggest Loser.

Oh how we studiously avoid this program. Not because it's not good, actually quite the opposite. It's not going to win any Peabodys any time soon, but the show — a reality series about people competing to lose weight — has a specific kind of struggle and ultimate uplift to it that is pretty unrivaled in primetime reality programming. The reason we avoid it is because of this; the minute you're ensnared by the tearjerking need to see everyone happy and skinny at the finale, there is no way you won't stay on and watch until the end. We fell into this trap last night. Damn you, Ringer! If only you'd been on!

The main problem with watching The Biggest Loser: Every episode is two agonizing hours long, when really all we want to see is a little of the exercising stuff, a little of the crying stuff, and then the final weigh-in. But no, we must suffer and endure some 92 minutes of wheezing and moaning and food craving. And it can be so hard, yet so compelling, to watch. Last night's episode (the second of the show's 13th season) involved the simple "OK, see, this isn't so hard" satisfaction of the nutritionist's visit, in which she explains calmly and non-condescendingly that ranch salad dressing kinda negates the purpose of a salad and that eating three rolls of sushi in the car on the way home to dinner is maybe not the best idea, but also the more existential and "This is going to be a longgg road" despair of a physician's visit, in which he explained to two particularly bad-off contestants that they have pre-diabetes, that really they're headed toward an early grave unless things change. That's the stuff on this show that is depressing and unsettling to watch, and were the entire episode like this, we'd shudder and turn the channel away and not watch again.

But, to the woe of our precious free time, that of course is never the whole episode. The scary stuff is always there, but mostly there is all the crying and grunting and blonde Wonderbread cheers of the show's near-genius host Alison Sweeney. Is there any other reality show host who gets so clearly emotionally involved in her charges' lives? Sweeney just really seems to care, and is not afraid (we do not think this has become cynical enough an endeavor that she's forcing it, not yet at least) to show it. She is the stand-in for all of us at home, rooting for these typically good and decent people as they try to do what is probably one of the harder, if not the hardest, things they'll ever have to do. And so when you stumble across everyone sweating and trying, and Alison all encouraging there on the sidelines, well, then they've got you. How can you abandon everybody now? Now you're invested, you're part of the team!

It's not enough to just tune back in at the finale. You need to see the progress, need to understand the dynamics of everyone's story so the the thrill of victory is that much more thrilling and the agony of defeat that much more agonizing. This is a cannily crafted show, one that makes it near impossible to not care about a randomly caught standalone episode to such a degree that — plans be damned, you'll have to shuffle around the recording schedule on your DVR, sorry but it's inevitable — devotion to the rest of the season becomes a requirement, almost a calling. It's a strange, sweet drug, and we got (once again) suckered in last night.

So that will be our Tuesdays (or at least part of them) for the next 18 weeks. If only we'd just stuck with that rerun of SVU! But what can you do? Santa Claus and his wife are on this season. We have to help them get skinny!