BETA

The simplest weight loss system
that actually works.

No calorie counting. No food logging.
No meal plans. Just four daily rules —
and a streak worth protecting.

Try FOUR free → or take the quiz first →

Not medical advice. Individual results vary.

Why most diets fail

Too complicated to sustain
Calorie counting, macro tracking, meal prep. The mental load is exhausting. Most people quit not because they lack willpower — but because the system demands too much.
One bad day breaks everything
Most diet systems are fragile. Miss one day and the streak is gone. The psychology of "I've already failed" turns a single slip into weeks of abandonment.
Results are too slow to feel real
When the feedback loop is weeks long, motivation collapses. You need to feel progress daily — not just on the scale.

How FOUR works

One goal. Four rules. A streak worth protecting.

01
No Liquid Calories
Water, sparkling water, black coffee, plain tea — nothing else.
Your body doesn't register liquid calories the same way it registers food. A latte is 200 kcal your brain never accounts for.
02
No Snacking
Three meals, nothing between. A handful of nuts still counts.
Every time you eat, insulin rises. Keeping meals to three windows lets insulin drop between them — the condition your body needs to burn stored fat.
03
10-Hour Window
First bite to last bite within 10 hours. 8am start means finish by 6pm.
A 10-hour eating window creates a 14-hour overnight fast. During this fast, your body shifts from burning incoming food to burning stored fat.
04
Exercise
A 20-min walk counts. So does 45 mins in the gym. Anything deliberate.
Daily movement improves insulin sensitivity — meaning your body handles food more efficiently. The bar is intentionally low.

The streak mechanic

12

day streak

FOUR tracks your streak — the number of consecutive perfect days. Every day you follow all four rules, it grows. Miss a day and it resets. That single number becomes surprisingly powerful. You'll find yourself thinking about it at dinner. You won't want to break it. This is loss aversion working in your favour.

Streak Freezes

Miss a day? Use a freeze token to protect your streak. Earn one for every 5 perfect days — or get 2 guaranteed per month with Pro.

What beta testers say

★★★★★

"I've tried calorie counting, meal plans, every app. FOUR is the first thing that's actually stuck. The streak makes it feel like a game I don't want to lose."

— Peter, Zurich
★★★★★

"I was sceptical about only four rules. Two weeks in, I realised the simplicity is the point. I don't have to think about it."

— Rebecca, United Kingdom
17
beta testers
82%
daily return rate
4
rules. that's it.

Simple pricing

Free
$0
forever
  • Daily rule tracking
  • Streak counter
  • Basic badges
  • Calendar (last 14 days)
  • Weight tracking (last 14 entries)
  • 1 personalised insight at day 7
Get started free →
MOST POPULAR
Pro
$7.99
per month
  • Everything in Free
  • Full calendar history
  • Full weight history
  • Complete insights
  • Weekly personalised coaching
  • 2 guaranteed streak freezes/month
  • Community Intelligence (coming soon)
Coming soon

Common questions

Is this safe? Is it medically approved?+
FOUR is a lifestyle app, not a medical device. The four rules are general healthy lifestyle guidelines — avoiding liquid calories, eating at regular mealtimes, maintaining an eating window, and exercising daily. They are not a substitute for medical advice. If you have a health condition, are pregnant, or take medication, consult your doctor before making dietary changes. See our full disclaimer at four-app.com/policies.
What if I miss a day?+
Your streak resets — but your data doesn't. You can earn streak freeze tokens (one for every 5 perfect days) which protect your streak when you miss a day. More importantly, one missed day doesn't undo the habit. Open the app the next morning and start again.
How is this different from intermittent fasting?+
The 10-hour eating window is similar to 14:10 intermittent fasting. But FOUR combines it with three other rules that work together — no liquid calories eliminates hidden intake, no snacking keeps insulin low between meals, and daily exercise improves how your body uses food. It's a complete system, not just a fasting timer.
Is FOUR free?+
The core features are free forever — daily tracking, streaks, badges, and 14 days of calendar history. A Pro tier (6 CHF/month) is coming soon with extended history, weekly personalised coaching, and guaranteed streak freezes.
Does it work for everyone?+
FOUR works best for people who want a simple, sustainable system rather than a restrictive diet. It's not designed for people with specific medical dietary requirements. Individual results vary — weight loss depends on many factors beyond the four rules.
Do I need to count calories or track macros?+
No. That's the point. The four rules are designed to create a calorie deficit naturally — by eliminating liquid calories, reducing snacking, compressing your eating window, and increasing movement — without requiring you to count anything.

Start your streak today.

Free forever. No credit card.
Takes 60 seconds to set up.

Try FOUR free → or take the quiz first →