What to track in your first twelve weeks

Because a review is coming, and it is partly a decision about numbers.

Each of these treatments carries a point at which a prescriber formally asks whether it is working — against a threshold of 5% of starting weight, at a moment that differs by medicine. That conversation goes differently depending on whether you arrive with a record or with an impression. "I think it settled after a few weeks" and "nausea from day 3 to day 19, worst in week two, gone by the time I reached 5 mg" lead to different clinical decisions, because only one of them is evidence.

The second reason is that the early weeks are when the useful signal appears and also when memory is least reliable, because several things are changing at once.

Once a week, same day, two minutes. Everything else is optional.

Scale weight cannot distinguish between the kinds of tissue you lose, and on this class of treatment that distinction matters. Losing weight is the goal; losing a disproportionate amount of muscle while doing it is not, which is the subject of our guidance on protein and muscle during treatment.

Waist circumference adds information weight does not. It tracks where fat is being lost rather than only how much mass has gone, and abdominal fat is the deposit most closely tied to blood pressure, blood glucose and cardiovascular risk. A week where the scale has not moved but the tape has is a real result, and without the tape you would have recorded it as a failure.

This is also the most common reason people stop too early. Weight plateaus are normal and they are not evenly distributed in time. If the only thing you measure is the number that plateaus, you will conclude that nothing is happening during the weeks when quite a lot is.

Record the dose, every week, including the weeks nothing changed. This is the entry people leave out and the one a prescriber most wants.

The reason is in how the review works. For tirzepatide the clock to that review starts when you reach the highest dose you can tolerate, not when you start treatment. For semaglutide the six months run from the start, but around sixteen weeks of that is spent escalating. So "how long have you been on treatment" and "how long have you been on a dose that could reasonably be expected to work" are different questions with different answers — and the second one is the one that bears on whether the treatment has had a fair trial.

If you held at a lower dose for six weeks because of nausea, that is not a failure to report. It is the most important context for interpreting everything else you recorded, and without it a flat result looks like non-response when it was actually an incomplete trial.

Gastrointestinal effects are the common ones: nausea, reflux, constipation, diarrhoea, feeling full very quickly. They tend to cluster in the first weeks and after each dose increase, which is itself the pattern worth capturing — a symptom that appears three days after every escalation and fades is telling a different story from one that never goes away.

Record severity roughly rather than precisely. Mild, manageable, or stopped me doing something is enough resolution to be useful, and more precision than that tends not to get recorded at all.

Separately, and not as part of any tracking exercise: severe abdominal pain that may spread to your back, swelling of the face, lips or throat, difficulty breathing, or being unable to keep fluids down need urgent medical attention now, not an entry in a log. The side-effects guide sets out which symptoms are which.

Daily weight. It will mislead you and it will make you miserable, which is a bad combination.

Day-to-day fluctuation is dominated by water, food still in transit and the time of day — routinely a kilogram or two in either direction, which is larger than a real week of change. Weighing daily means you spend most of the week looking at noise and reading it as signal. The pattern is only visible weekly.

Also not worth tracking: calories, unless someone has specifically asked you to. These medicines work by changing appetite, and the usual experience is eating less without counting. Adding a counting habit on top frequently reintroduces the relationship with food that the treatment was supposed to interrupt.

One row per week, six columns, kept anywhere you will actually keep it — a notes app, the back of a diary, a spreadsheet. The format matters far less than the habit.