Developer builds AI fitness coach that tracks body changes from photos instead of manual logging

A developer shared an AI fitness coach tool on Hacker News that analyzes weekly selfies to monitor progress toward fitness goals, eliminating the need to manually log workouts or count calories. The creator has tested it on themselves at the gym for the past year.

Instead of requiring users to input sets, reps, and macros (nutritional targets), you upload a photo and the AI compares your body to your goal, then recommends specific plan adjustments — turning a tedious tracking task into a single weekly photo.

For gym-goers and people on structured fitness plans, this removes a major friction point: the daily logging habit that most people abandon. Rather than spending 10 minutes typing data after each workout, you get actionable feedback from visual progress alone, making long-term goals feel more concrete and achievable.

The tool is live at roadmap-project-bygrl.vercel.app and open to test; the code appears to be publicly available, though it currently has minimal engagement (1 point, 1 comment on Hacker News as of posting).