Why tracking works
Self-monitoring is one of the most replicated findings in weight-management research: people who record their weight and food intake lose more and, more importantly, regain less. On a GLP-1 the effect compounds. Your notes become the data your prescriber uses to time dose changes, spot side-effect patterns, and catch regain early. Two kilograms caught early is a two-week fix; ten caught late is a different conversation (see maintenance after Mounjaro).
The four numbers that matter
The apps, by job
Purpose-built GLP-1 trackers
A wave of dedicated shot-tracking apps has appeared alongside the UK GLP-1 boom. The good ones share a template: dose scheduling with reminders, injection-site rotation maps, weight charts, and side-effect logs. When choosing one, check: does it work offline, does it export your data (CSV/PDF for your prescriber), and (read this twice) what is its privacy policy on health data? An app that sells "anonymised" injection data is not one to keep.
Food and protein tracking
- Macro/food trackers (the big-name calorie apps all do this): use them for the protein number, not calorie guilt. Set a custom protein goal and let calories do what they do.
- NHS-backed options. The NHS food and activity apps are free, privacy-safe, and integrate sensibly with UK guidance; less slick, but nothing is being sold.
Weight trend apps
Dedicated weight-trend apps smooth daily fluctuations into a moving average. Psychologically valuable when a salty meal adds a fake kilo overnight. Pair any of them with weekly same-time weigh-ins.
The paper option (genuinely fine)
A notebook with four columns (dose, weight, protein, notes) beats the fanciest app abandoned after three weeks. Consistency is the feature; the medium is irrelevant.
A five-minute weekly routine
- Same time weekly: weigh, log, look at the four-week trend. Not the week.
- Scan side effects: any pattern tied to dose days? Worth raising at your next review?
- Protein audit: hitting target at least five days of seven? If not, plan two protein anchors for next week.
- Injection logistics: next dose day set, site rotated, pen supply checked (reorder before the last pen. See delivery timing).
Health data is the most sensitive data you own. Prefer apps that store data on-device or offer clear UK GDPR-compliant policies, skip "sign in with social media" where possible, and export your log regularly so it is never hostage to a startup's fortunes.
Frequently asked questions
What should I track while taking Mounjaro or Wegovy? +
Four things: doses (date, dose, injection site), weekly weight, daily protein, and a brief side-effect note. That covers efficacy, safety and muscle preservation with about five minutes of effort a week.
Are GLP-1 tracking apps safe for my data? +
Varies widely. Check the privacy policy before logging anything. Prefer on-device storage, UK GDPR compliance, and data export. Avoid apps that monetise health data or require social logins for sensitive tracking.
Should I weigh myself daily or weekly on a GLP-1? +
Weekly at the same time is the sustainable default. Daily weighing works if you can treat it as data rather than drama. Weight fluctuates 1 to 2 kg with water and bowel contents. Trend over weeks, never single readings.
Is tracking calories necessary on Mounjaro? +
No. Appetite suppression handles the deficit for most people. Protein is the number worth tracking, because it protects muscle and does not come automatically when appetite is low.
Can I share my tracking data with my prescriber? +
Yes, and you should. Dose dates, weight trend and side-effect notes are exactly what a prescriber needs for titration decisions. Choose apps that export to PDF or CSV, or photograph a paper log.
References & official sources
Show all 4 cited sources, with study authors +
- NICE NG246. Overweight and obesity management (self-monitoring and behavioural support): www.nice.org.uk/guidance/ng246
- NHS. Better Health: weight loss tools and apps: www.nhs.uk/better-health/lose-weight/
- NICE TA1026. Tirzepatide for managing overweight and obesity: www.nice.org.uk/guidance/ta1026
- NICE TA875. Semaglutide for managing overweight and obesity: www.nice.org.uk/guidance/ta875