Lena Osei had been through four programmes before this one, and could recite the pattern: intense start, early result, quiet collapse around month five.

Maintenance is its own phase with its own skills, and the team treats it as harder than the losing phase rather than as a victory lap.

The programme front-loads almost nothing. The first phase changes two things and no more, which most people find insulting for about three weeks and survivable after that.

We build for the fifth month, because that’s when the enthusiasm is gone and the habit has to carry it.

Illustrative composite

There was a plateau from about week twenty. Nothing was going wrong; the body had simply arrived somewhere and wanted to stay there for a while.

Eleven months in, she is past month five for the first time in her adult life.