For skinny guys who can't eat enough

Bulking meals built to
make eating big easy.

Big, calorie-dense meals with every ingredient and cooking step laid out, so hitting a surplus stops being a chore. Free.

★★★★★ 5.0 on the App Store
Download on the App Store Watch how it works28 seconds

No subscription · no ads · no accounts
free because you bring your own AI

9:41
‹+
JUN 9
Tuesday
117 / 239g protein · 1,580 / 3,311 kcal
2 of 5 eaten
Timeline
6:00 AM · BREAKFAST
›
Protein Pancakes
760 kcal · P52 C74 F27
9:00 AM · BRUNCH
›
Steak & Eggs
820 kcal · P65 C37 F44
12:30 PM · LUNCH
›
Slow-Cooked Massaman Beef Curry
890 kcal · P52 C42 F58
4:00 PM · SNACK
›
King Kong Chocolate
1418 kcal · P85 C93 F79
7:30 PM · DINNER
›
Slow-Cooked BBQ Pulled Pork
610 kcal · P48 C28 F32
exercise demo
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Barbell Back Squat ▾
Quads · Glutes
Week 13 × 10, 10, 8
SETKGREPS✓
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Barbell Back SquatCURRENT
3 × 10, 10, 8 · 0/3 done
Romanian Deadlift
3 × 10 · 0/3 done
Leg Press
3 × 12 · 0/3 done
Back Extension
3 × 12 · 0/3 done
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Start Workout
Tap to switch
Works with ChatGPTClaudeGeminiDeepSeek + any AI
The Meal Library

Real meals,
step-by-step.

Browse a whole library of calorie-dense meals with exact ingredients and cooking steps, built to make eating big easy. High protein comes standard.

Slow-Cooked BBQ Pulled Pork
Australian · Pork
Slow-Cooked BBQ Pulled Pork
48g P28g C32g F610 kcal
 Red Wine-Braised Lamb Shanks
Australian · Lamb
Red Wine–Braised Lamb Shanks
54g P14g C58g F825 kcal
 Slow-Cooked Massaman Beef Curry
Thai · Beef
Slow-Cooked Massaman Beef Curry
52g P42g C58g F890 kcal
 Steak and Eggs
Breakfast · Beef
Steak & Eggs
65g P37g C44g F820 kcal
 Protein Pancakes
Breakfast · Dairy
Protein Pancakes
52g P74g C27g F760 kcal
 King Kong Chocolate protein smoothie
Smoothie · Dairy
King Kong Chocolate
85g P93g C79g F1418 kcal
Browse all meals →
FREE
JSON.fit
The Skinny Guy's Bulking Cookbook
81 calorie-dense meals · macros + grocery lists
Free Cookbook + Updates

Get all 81 bulking meals as a printable cookbook, free.

Macros, ingredients and a grocery list for every meal — yours to keep and print. Plus new meals as they land, what's working in my own bulk to 90kg, and a say in what I build next.

✓ Check your inbox — your cookbook's on the way.

No ads, no spam. Unsubscribe anytime.

How your plan gets built

Choose your meals, build your week.

01 · You

Answer a few questions

Your specific goal, height, weight, activity and the meals you actually like. JSON.fit turns your answers into a prompt to copy.

Weight gain90kg6 meals/day
02 · Any AI

Paste your prompt into any AI

Your prompt is packed with real research, so the AI builds your plan on proven science, not guesswork.

ChatGPTClaudeGemini
03 · Back in

Import the file it makes

The AI turns your plan into a file. Import it into JSON.fit for every meal, your exact macros, a grocery list, step-by-step recipes and meal prep guidance.

0.81s import7-day plan

Same system builds your training program too: splits, volume per muscle, deloads, progressive overload — and you can build one that runs up to a year long.

Not generic AI

Built on real nutrition science,
not a one-line prompt.

Structured, not random

Real daily meal structure and calorie targets across your whole week, not the same three meals on repeat.

Calibrated to you

Macros dialled to your bodyweight, goal and surplus, with your protein target hit every single day.

Checks its own work

A review pass verifies your calories and macros add up before the plan ever reaches your import.

"Already pay for ChatGPT Plus so I was sick of other apps charging me again for the same thing. JSON.fit lets me use my own AI and just handles the tracking. Workout imports are completely free."

★★★★★ Zac ishiyama · App Store
See It Working

Real AI output.
Real meal plans.

An actual user's plan, generated and imported with Claude.

Claude Output

See the actual plan, screen by screen

A user's plan, imported with Claude. Swipe through the app screens.

Meal plan imported in 0.81s Daily meal timeline with macros Grocery list and meal prep schedule Itemised grocery list with prices Step by step meal prep session
Full tutorial: meal plan with Claude
Macros Verified

Every gram tracked. Every day covered.

A 7-day bulk plan, generated with Claude.

Weight Gain90kg · MaleHigh Calorie6 meals/dayAldi · Canberra
Protein
229g
Carbs
368g
Fat
139g
Fibre
42g
3,629kcal · Saturday
$230weekly groceries · Aldi Canberra
Free Training Programs

Eating big adds the weight.
Training makes it muscle.

Don't want to build a custom plan? Import a complete, periodised program that runs a full year, directly into the app, instantly.

Upper / Lower

Beginner Foundation

4 training days · 3 rest
52 weeksBeginner
View program PPL + Upper/Lower

Intermediate Hybrid

5 training days · 2 rest
54 weeksIntermediate
View program Push / Pull / Legs ×2

Advanced High-Volume

6 training days · 1 rest
52 weeksAdvanced
View program
Compare

Premium personalisation.
Zero cost.

The kind of programming and nutrition that used to cost a fortune, now completely free.

JSON.fit
Dietitian / PT
Other Apps
Typical cost
Free
$150–300 USD/session
$20–60 USD/mo
Expert-level personalisation
✓
✓
Basic
Instant access
✓
Weeks wait
✓
Unlimited plan changes
✓
✗
✗
Grocery lists
✓
✗
✗
Meal prep guidance
✓
✗
✗
No ongoing fees
✓
✗
✗
AI provider choice
Yours
N/A
Locked in
App Store Reviews

What people are saying.

5.0 ★★★★★ 8 ratings · App Store
★★★★★
Awesome app, fitness plans

Created me a 12 week fitness plan for all my personal priorities. Was even able to add additional preferences via AI.

Rory@TVX · 23 May · Australia
★★★★★
Replaced my $30/month PT app

Was paying for an AI trainer that was just GPT under the hood anyway. This app lets me use ChatGPT myself to build my program and just handles the tracking. Workouts are completely free too which I wasn't expecting.

ReeceAdam · 31 Mar · Australia
★★★★★
Finally an AI fitness app that doesn't charge you for AI

Already pay for ChatGPT Plus so I was sick of other apps charging me again for the same thing. JSON.fit lets me use my own AI and just handles the tracking. Workout imports are completely free.

Zac ishiyama · 4 Apr · App Store
· No subscription. Ever.

Everything free.
No catch.

$0to use

No subscription · No paywall · No ads · No accounts

✓ Full bulking meal library, step-by-step
✓ AI meal plans built around your macros
✓ Free year-long training programs
✓ Smart grocery lists & pantry intelligence
✓ Works with ChatGPT, Claude, Gemini & more
✓ No ads. The app collects no data. Ever.
Download on the App Store

🔒 Your data stays on your device. Always.

📱 iOS only · Android in development

FAQ

Common questions.

Three steps:
1. Answer a few quick questions.
2. Paste the prompt JSON.fit makes into any AI like ChatGPT, Claude or Gemini.
3. Import the meal plan it builds and start tracking.

The same flow builds your training program too.
Most AI chatbots have a free tier that works perfectly. ChatGPT, Gemini and others all offer free access. If you're already paying for a premium AI subscription, even better. Either way, JSON.fit itself has no AI costs to pass on to you.
It's completely free. Workouts and nutrition are all free: meal plans, macro tracking, grocery lists, meal prep and pantry intelligence. No subscription, no paywall, no in-app purchases.
There isn't one. Most fitness apps charge $10–20/month because they run AI on their own servers. JSON.fit uses the AI you already have, so there are no server costs to pass on. There are no ads or accounts either, and the app itself collects no data — the website only runs basic anonymous analytics. There's nothing to sell. The app is simply free.
Any AI that can generate structured text, like ChatGPT, Claude, Gemini and DeepSeek. You're not locked into one provider. Use whatever you prefer.
Yes. Your data stays on your device. JSON.fit doesn't have accounts, doesn't collect personal information, and doesn't send your workout or nutrition data anywhere.
Not yet. It's currently iOS only, but Android is in development.