James Chambers was watching membership sign-ups on Jan. 4, 2015, like a stock ticker — it was that first Sunday of the year, the day we all decide that this is it, we’re not going to stay fat for one more day. At the time, he was Weight Watchers’ chief executive, and he sat watching, waiting for the line on the graph to begin its skyward trajectory. Chambers knew consumer sentiment had been changing — the company was in its fourth year of member-recruitment decline. But they also had a new marketing campaign to help reverse the generally dismal trend. But the weekend came and went, and the people never showed up. More than two-thirds of Americans were what public-health officials called overweight or obese, and this was the oldest and most trusted diet company in the world. Where were the people? Weight Watchers was at a loss.

Today, Donna had gained weight. She had been holding steady at six pounds short of her goal. Since 2009 — 2009 — she had shown up every week and by now had lost 132 pounds, which is an entire other Donna. But these last six pounds, my God, what would it take? She’d been down last week by a pound, and now that pound was back. She’d been going to the gym ‘‘religiously’’ for two weeks, but thought maybe the not going to the gym three weeks ago had caught up with her. Sometimes being six pounds away from her goal was harder than being 321 pounds.

‘‘I’m so frickin’ aggravated,’’ she said. She asked me how I did. I shrugged and told her I had lost three pounds. ‘‘But I just started, so, . . . ’’ I said. I didn’t want her to feel bad. Another woman, Amy, whispered to me, ‘‘You never want to say ‘I only lost, . . . ’ because then everyone will go, ‘Oh, jeez.’ ’’