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Four things decide your fitness.

Stack connects food, training, sleep and steps. And shows you what to fix first.

Download on the App Store

7 days free.

Works with Apple Health
The Food tab after lunch: 1,135 of 2,000 to 2,200 calories
A workout: set 1 hit 6 reps with 2 in reserve last time, add the smallest plate.
The Brief: weight down 0.34% a week, slower than the aim; sleep mostly rough; food up and down; workouts dropping; steps 6,303 a day.
The Brief

It sees everything. You fix the right thing.

So you stop cutting calories when the real problem is your sleep.

The Brief. Weight: down 0.34% a week. Sleep: mostly rough. Food: up and down. Workouts: dropping. Steps: 6,303 a day. Your weight is coming down 0.34% a week, slower than the 0.5 to 1% a week we aim for. Rough nights make it hard to stay within your calorie range, and they hold your training back. Focus: keep the last hour calm: no email, news or scrolling.
Food

Take a photo.

Works on a plate, a menu or a label. Or just say what you ate.

  1. The food camera pointed at a chicken burrito cut in half, with the shutter, Photos, Speak and Type

    1Snap your lunch

  2. Chicken burrito with rice and black beans, 805 calories, counted as 1 large, and the button: Add to today’s lunch

    2It reads the whole burrito

  3. The day after lunch: 1,135 of 2,000 to 2,200 calories, protein behind for the hour, and a scoop of protein powder as the next step

    3Your day so far

Menus

Point it at the menu.

See which dish fits the rest of your day.

  1. The food camera pointed at a dinner menu

    1Snap the menu

  2. What I’d order here: grilled salmon, most protein for the fewest calories on this page, about 660 calories and 60 g protein, ticked. Log 1 dish.

    2It picks what to order

  3. The day while traveling: 2,142 of 2,000 to 2,200 calories, protein 155 g, read back as a road day that landed inside the range; dinner, grilled salmon, 660 calories and 60 g protein.

    3Dinner logged, day on target

Training

It shows you how to train.

And tells you when to add weight.

  1. A superset: DB bench press, then straight into the chest-supported row

    1Follow your program

  2. 2Watch how it’s done

  3. Set 1 hit 6 reps with 2 in reserve last time: add the smallest plate. Set 1 logged at 235 lb for 6, the rest timer running.

    3Add the smallest plate

SupersetsDrop setsRest-pause

AI

Your AI builds your workouts.

Connect ChatGPT or Claude. It knows your food, training, sleep and steps, writes your program and coaches you through it.

A hotel gym: benches, a barbell with plates and a dumbbell rack

I’m in Austin till Friday. This is the hotel gym. Can you build me 3 days?

Got it: dumbbells, cables, a barbell and benches.

Your entire routine will be ready in Stack in 5 minutes, with videos and rest times set.

Because of your lower back, each day starts with mobility, and your deadlifts are now B‑stance dumbbell Romanian deadlifts.

Day 1 Upper body · Day 2 Lower bodyDay 3 Full body · 25 minutes each

I slept 5 hours. Should I still train today?

That’s your call. If you want to go, go.

Your warm-up sets will tell you how hard to push today.

If the weights feel heavier than usual, keep your sets lighter and leave the heavy work for a better night’s sleep.

Questions

Does it work with Apple Health?

Yes. It reads your steps, sleep, weight and workouts, and saves your meals, workouts and weigh-ins back to Health.

How do I set my calories and macros?

You don’t. Answer a few questions when you start, and Stack sets your ranges.

Do I have to count every calorie?

No. Take a photo or tap your usual. Landing in your range most days is what counts.

I’m too busy for this.

It takes seconds: two taps in the morning, a photo at each meal. Or tell Siri: “Log my weight in Stack.”

How does it work with my AI?

Tap Connect your AI in Stack. ChatGPT or Claude reads your food, training, sleep and weight, and builds your workouts. Disconnect any time.

What does it cost?

7 days free, then $29 a month.

Start with your next meal.

Download on the App Store