Fitzy: weekly meal plans for diet coaches, offline on the desktop

The business problem

A diet coach's real product is the weekly meal plan: what each client eats, at what time, against a daily calorie goal. For many coaches, the tools behind that plan look like this:

• Diet charts on paper or in Word, rewritten from scratch for every client, every week.
• Plans sent as chat messages or photos, which clients scroll past and lose.
• Client details in a notebook: weight, height, goal and programme length.
• No overview: it's hard to see which clients still need this week's plan.

Generic diet apps don't help much either. Their food lists are built around foods the coach's clients don't eat. A coach whose clients eat idly, dosa, pongal and sambar needs their own food list, not a database of foods nobody here eats.

The goal for Fitzy: let a coach manage clients and build a clean weekly plan in minutes, hand it over as a professional PDF, and run it all on their own computer, even without internet.

Why existing solutions failed

• Paper and Word: slow to write, impossible to search, and every week starts from a blank page.
• Chat messages: a plan sent as text gets buried under the next hundred messages, and there's no clean copy to print.
• Spreadsheets: flexible, but easy to break, hard to read on a phone, and they don't know who your clients are.
• Online diet platforms: monthly fees, generic food databases, the coach's client data on someone else's server, and no work when the connection drops.

The solution

Fitzy is a desktop app for diet coaches. It installs like any Windows app, opens to a dashboard, and keeps every client and plan on the coach's own PC.

1. See who needs a plan

The dashboard shows total clients, plans created, and how many clients still need a meal plan, so nobody slips through. Recent clients are listed with a clear Has plan / No plan flag and a link straight to their plan.

2. Every client in one place

Each client has their contact details, programme length (1, 3 or 6 months), weight, height and daily calorie goal. Adding, editing or removing a client takes a single form, and one click opens their meal plan.

3. A weekly planner built for speed

This is the heart of the app.

• Seven days × six meal slots: Pre Breakfast, Breakfast, Pre Lunch, Lunch, Post Lunch and Dinner.
• Editable meal times per slot, for example "5 AM – 7 AM".
• Calories per day shown against the client's goal, so it's obvious when a day is over or under.
• Weeks start on Monday, with Previous / Next buttons and a month picker to jump to any week. Every week is saved separately, so past plans stay available.
• A food list that learns. Type a few letters and Fitzy suggests foods from the coach's own list, without repeating ones already added. Foods are shown as chips. Any new food typed into a plan is added to the list automatically on save, so the list grows to match the coach's own way of working.

4. One-click PDF handout

Export PDF creates a landscape A4 handout with the client's name, the week, the calorie goal and the full 7 × 6 plan with meal times. It's clean enough to print and stick on the fridge, or to send on WhatsApp.

5. Desktop, offline and backed up

• Installs like any app: a Windows installer with Start menu and desktop shortcuts. The build is also configured for macOS and Linux.
• Works without internet: the whole app runs on the computer itself.
• Data stays on the PC: clients, plans and the food list are stored in the user's own app-data folder, not on a remote server.
• Backup and restore in one click: export everything to a single dated backup file, and import it on a new computer.

Key features

• Dashboard showing which clients still need a plan.
• Client management with goals, measurements and programme length.
• Weekly meal planner: 7 days, 6 slots, editable times and calories per day.
• Food suggestions from the coach's own list, which grows automatically.
• Week history: any past or future week, one click away.
• Landscape A4 PDF export.
• Offline desktop app with a Windows installer.
• One-click backup and restore.

Technical architecture

• Frontend: Next.js 15 (App Router) and React 19, React-Bootstrap UI, TanStack Table, Redux Toolkit.
• Backend: Next.js API routes for clients, meal plans, foods and backup, all in the same app.
• Storage: JSON files in the user's app-data folder. Every write goes to a temporary file first and is then renamed into place, so a crash or power cut can't leave a half-written file.
• Desktop: Electron starts the Next.js server as a background process on localhost only, waits until it responds, then opens the window. Links to outside sites open in the normal browser, and the server shuts down with the app.
• Packaging: electron-builder creates the Windows installer, plus a small script that makes sure the server's dependencies are included in the package.
• PDF: jsPDF draws the A4 handout in the app itself, with no external service.

Challenges

Running a full web app as a desktop app. Fitzy needs its API routes, not just static pages. The answer was to bundle the complete Next.js server and run it as a background process inside Electron, so no Node.js install is needed on the coach's computer.

Packaging the server's dependencies. The installer builder skipped the server's own dependencies. A post-package step copies them into the build, so the installed app starts correctly.

Keeping local data safe. With no database server, a crash during a save could corrupt a file. Writing to a temporary file and renaming it means a save either completes fully or doesn't happen at all.

Plans saved in older formats. As the plan format changed, older plans stored meal names in different styles. The planner reads every known style and normalises it, so old weeks still open correctly.

Food lists that fit the coach. Instead of a fixed food database, the list starts small and grows from the coach's own plans, so local dishes work from day one.

The outcome

• A complete weekly-planning workflow in one app: client, plan, PDF.
• Plans are reusable and searchable instead of retyped from paper every week.
• A professional handout for every client in one click.
• No subscription, no server and no internet dependency, with client data kept on the coach's own computer.

What's next

The roadmap for the admin side includes workout routines linked to diet plans, subscription and payment tracking, trainer and nutritionist accounts, progress reports, and a Tamil/English language toggle.

What this means for other businesses

Build around the deliverable. For a diet coach, the weekly plan is the product. Making that one thing fast and professional mattered more than any other feature.

Local-first is a feature. For small practices, "it works offline and the data stays on my PC" is a real selling point, not a limitation.

Let the tool learn from the user. A food list that grows from the coach's own plans fits better than any generic database could.

If you run a practice that still lives on paper and chat messages, I'd be glad to help you turn your core deliverable into a tool like this.