Arrow automatically updates your calories, protein, carbs and fats when your training stalls, when your weight gain stalls, or when you're gaining too quickly. Arrow can spot those cases because your lifting log, food log and weigh-ins are in one app.
Below is what Arrow reads, what an update looked like for me, and which detection details we haven't published yet. If you don't use Arrow, the last section shows how to run the same weekly check by hand.
Disclosure: I make Arrow. Everything about Arrow on this page comes from the App Store listing, arrowfitnessapp.com, our existing journal pages, or my own use of the app, checked 2026-11-04. Where we haven't published the details, I say so.
01What counts as a stall in Arrow?
Arrow updates your calories, protein, carbs and fats on its own when training stalls, when weight gain stalls, or when you're gaining too quickly. A stall shows up in one of two ways:
- Your weight trend isn't moving. You're on a muscle-gain plan, you've followed it for about a week, and your weight hasn't gone up.
- Your lifts aren't going up. The numbers in your log have stopped climbing.
Gaining too quickly is separate from a stall, and it updates the same targets.
On the training side, Arrow tracks progress against a rep range. You log your sets, and when you reach the top of the range, the next session's target goes up. When you stop reaching the top of the range and the target stops moving, that's the lift version of a stall.
We haven't published the exact rule behind the lift version, such as how many sessions count or which lifts it looks at. I'd rather tell you that than guess.
02What does an update look like?
Here's what happened to me. I was on a muscle-gain plan, and after about a week my weight wasn't going up. Arrow updated my targets without me asking: based on my weight trend and what I'd logged eating, it raised my calories and carbs.
That's one case, and I'm not going to turn it into a rule. What I can say for sure:
- It updates on its own. Arrow changes calories, protein, carbs and fats when training stalls, when weight gain stalls, or when you're gaining too quickly.
- Any of calories, protein, carbs and fats can change.
- The direction and size depend on the situation. In my case, with my weight flat on a gain plan, calories and carbs went up. We haven't published how large each change is.
- You can still edit any target yourself. Arrow never locks you into its numbers (App Store listing).
03How does the loop work?
- You pick a goal. Lose weight, build muscle or maintain. The goal sets your workouts and your starting daily calorie, protein, carb and fat targets.
- You train and log food. Sets, reps and weight go in the workout log. Meals go in by photo (Smart Scan), voice, text, barcode or the food database. Steps come in from Apple Health.
- Your calorie target is checked every week against your weight trend. Adaptive TDEE compares how your smoothed trend weight moved with what you logged eating. It starts after about 7 complete logged days and 2 weigh-ins at least 7 days apart, and each weekly check-in moves your calorie target by at most 150 kcal (see how adaptive calorie apps work).
- If training stalls, weight gain stalls, or you're gaining too quickly, Arrow updates calories, protein, carbs and fats. An app that only tracks food can't react to your lifts, because it doesn't have them.
- Arrow Coach reads all of it. Coach looks at training and nutrition together, and the weekly recap covers both.
04What goes in, and what does it feed?
| Input | Where Arrow gets it | What it feeds |
|---|---|---|
| Goal | You set it in Arrow | Which workouts you get; starting calories and macros |
| Training log | The sets, reps and weight you log | Rep-range progression; the lift side of a stall |
| Steps | Apple Health | Calories and macros |
| Weigh-ins | You log them in Arrow | Trend weight; the weekly calorie check; the weight side of a stall |
| Food log | Smart Scan, voice, text, barcode, database | Adaptive TDEE (what you actually burn in a day) |
Steps matter because they change what you burn, including on days you don't lift. Having the training log next to the food log is what makes that update possible at all.
05When shouldn't a stall change your food?
Food is one of several things that can flatten a log. Bad sleep, a program that's run its course, a deload week, illness, a new job and missed sessions can all do it too. And if you only logged food on four days last week, the nutrition side is incomplete, and I wouldn't trust any app's read on it, ours included. You know about the bad week, and the app might not.
Read the training log, the food log and the weight trend together. On a cut, falling lifts plus a fast-dropping trend weight points at the deficit. On a bulk, flat lifts plus a flat trend weight usually means you aren't actually in a surplus. Our page on reading training and food together goes through more of these patterns, and the Arrow Score is the one-number version of the same idea.
06How do you run the same check without Arrow?
This is the weekly routine I'd use with any two apps. It's my own rule of thumb, not Arrow's internal rule.
- Write down four numbers every week: the top set on 2 or 3 main lifts, average daily protein, average daily calories, and the change in your 7-day average weight.
- Call it a stall only when two or more main lifts haven't gone up by a rep or a load jump for 2 to 3 weeks, and you've trained on schedule. On a gain plan, a flat weight trend after a week or two counts too.
- Check food before the program. Is protein at or near your target most days? Is the weight trend moving the way your goal says it should?
- Change one thing at a time. Protein first if it's short, then a small step in calories, something like 100 to 200 kcal, mostly from carbs on training days.
- Give it two weeks before you judge the change.
This works. The cost is that you're the one lining up two apps' numbers every week.
07Where does Arrow fall short today?
- We haven't published the full rule. How many sessions make a lift stall, and how big a change Arrow makes in each case, aren't public yet.
- It needs your food log. If you only log training, Arrow can't tell whether the stall is about food.
- It's paid. Arrow has one paid subscription with no free version. A 7-day free trial is available; the price is shown in the App Store.
- iPhone only for these features. The current version with these automatic updates and rep-range progression is on iOS. The Android app is an older version.
- No Apple Watch app is listed on the App Store page as of 2026-11-04.
08Sources
Checked 2026-11-04.
- Arrow App Store listing (description, subscription note, Coach recap, edit any target): apps.apple.com
- Arrow homepage (rep-range progression, suggested calorie target, Arrow Score): arrowfitnessapp.com
- Adaptive TDEE start condition and 150 kcal weekly cap: Which apps adjust your calories from your weight trend?
- Arrow Score components and toggles: What is the Arrow Score?
- Stall definition and the example above: my own use of Arrow, 2026-11.
This is general information, not medical advice. Talk to a professional before making changes that affect your health.