"Everyone's on one in January"

Some of the fresh starts aren't yours. The office starts one after Christmas and the kitchen fills with people comparing apps. Your sister rings with the name of a plan. January is a national fresh start, and to sit it out is to be the one who's given up.

I'd separate the company from the rules, as chapter 13 separated structure from rules. The office diet is company. People talking about food and their bodies and their weeks, checking in, cheering each other on. That's a good thing, and you don't have to give it up. What you'd be declining is the rules, and it's possible to have the first without the second. You can eat lunch with the people on the plan, hear how it's going, be pleased for them, and eat an ordinary lunch, and nobody will mind after the first day.

There's a version of this where the group is what makes the diet feel possible, and the group's ending is what makes the diet end. That's worth noticing on the envelope. If the office diets ended when the office lost interest, in the third week of January, then the group was the diet and the rules were along for the ride.

The other thing to say is that everyone being on one in January is the strongest evidence there is that they don't work. If January's diet held, there'd be no need for next January's, and the office wouldn't be doing it again. The fact that it's an annual event is the cycle at the scale of a country.

There's a version of the office diet that's a pact. You and a colleague start together, on the same Monday, and check in. The pact feels like support, and for a fortnight it is. Then one of you has the Thursday biscuit and the other one is now on a diet alone, and the pact becomes the reason both of you stop, because a diet for two was never a diet for one. If you want the company, keep the checking in and drop the rules. Two people eating ordinary lunches together and talking about their week is company that doesn't end on a Thursday.

Declining the rules doesn't need a speech. "I'm not doing one this year" is a full sentence, and if someone asks why, "I've done enough of them" is another. Nobody at the office diet is as interested in your plan as you fear. They're interested in theirs.