Pacer is a nutrition and training app for people who want to hit a protein floor, stay in a calorie target, respect an eating window, and train, without the app becoming a second job. It pairs a client app with a coach side, so a trainer can see a client’s day and bill them, all inside one product language.
The challenge
Most tracking apps confuse logging with insight. They ask for a lot, give back a wall of numbers, and make the daily ritual feel like data entry. The real problem was attention: the user needs to know, in one look, whether today is on track, and to fix it without thinking.
- The number you came for is buried under tabs and forms
- Logging a meal takes too many steps to become a daily habit
- Progress is shown as raw data, not as "are you on track?"
- Nutrition, fasting, training and supplements live in separate apps
- Dark mode is an afterthought, so the app is harsh at night
- Coaching tools are bolted on, with their own inconsistent UI
Discovery & research
Pacer started from a familiar failure mode, trackers that bury the one number you came for and turn logging into data entry. Discovery was about what makes a daily ritual stick, what a glanceable 'am I on track?' answer actually needs, and how to fold nutrition, fasting, training and coaching into one system without the bloat.
Logging dies the moment it feels like data entry
Most trackers ask for too much per meal, so the habit never forms. The research bar was a daily ritual you can complete in roughly two taps, which meant designing logging as fast search-and-confirm plus one-tap quick-adds, not a form.
EvidenceBuilt as a search-or-quick-add logging flow on the Today dashboard.
People want a verdict, not a number
'96 g protein' makes the user do the maths. The same figure as a coloured ring, a '44 g to go', or a green/red deficit card answers the question they actually have, am I on track right now? Every number is rendered as a judgement.
EvidenceThe Today screen leads with the protein ring and a state-coloured deficit card.
The day is split across four apps
Nutrition, fasting, training and supplements usually live in separate tools. Discovery scoped one system that carries all of it, so the design problem became density without clutter rather than feature breadth.
EvidenceFasting window, training plan, supplements and a GLP-1 schedule all live in the one app.
Food numbers have to be both fast and trustworthy
A tracker is only as good as its food data. Choosing a credible, comprehensive source meant the numbers behind every log could be trusted, which is what lets the 'verdict' colour mean anything.
EvidenceBacked by a USDA food database.
Coaching is usually bolted on with its own UI
Most apps treat the coach side as a separate, inconsistent product. Pacer modelled coach and client as one language, including a real billing link, so a trainer reads a client's day in the same system the client logs it.
EvidenceA dedicated Pacer Coach app, a client↔coach billing link, and a StoreKit paywall, all in one design language.
How I approached it
I built Pacer the way you build a system, not a screen. First a token layer, a warm, semantic colour set with light and dark values and a set of "state" colours that drive the deficit card. Then a component vocabulary: the Liquid Glass card, the protein ring, the metric tile, the quick-add. Every screen is assembled from that vocabulary, so the whole app stays coherent and flips to dark for free.
Defined semantic colour tokens, warm palette, light + dark, plus deficit states
Built a Liquid Glass surface and a small component library on top of it
Designed the Today dashboard around one hero: the protein ring
Reduced logging to a search-and-confirm flow plus one-tap quick-adds
Modelled the data so every number is also a colour-coded judgement
Extended the same language to onboarding, trends, schedule, paywall and the coach side
Trade-offs
The hard part was density without clutter. A real nutrition day has a lot in it, macros, fasting window, training, supplements, coaching. The screen had to carry all of it and still feel calm enough to read in a queue.
- Carrying real complexity without a cluttered screen
- Keeping one consistent surface (Liquid Glass) legible over a warm background
- Making dark mode genuinely first-class, not a tint
- Unifying client and coach experiences under one language
- Designing numbers that read as judgements, not just data
Final direction
The result is a single, glanceable system. The Today screen leads with the protein ring and a state-coloured deficit card; logging is a fast search-or-quick-add; trends, schedule, paywall and the coach surfaces all speak the same Liquid Glass language. Because everything is token-bound, the entire app flips to a fully designed dark mode in one switch.
Outcomes
Pacer is a fully designed, buildable iOS product rather than a flat mock-up, it builds and runs, with onboarding, a USDA-backed food database, fasting, training, supplements, a coach↔client billing link, and a StoreKit paywall. The design contribution is the system underneath: a token-first, component-led iOS app where coherence and dark mode are structural, not manual. [Add a live metric once shipped: day-1 logging rate / retention.]
Every number should also be a verdict.
A tracker is not really about tracking. It is about answering one question, "am I on track right now?", fast enough that the user keeps coming back. The system exists to make that answer instant.