The workout app for weight loss that keeps your muscle
Published October 27, 2026
When you're losing weight, the workout's job is to keep the muscle you have while the diet takes off the fat. That means lifting two to four times a week, with weights that hold steady on low-energy days instead of dropping. RIRLift runs that on iPhone and Apple Watch, free. Log weight, reps and how many reps you had left, and each session's weights are set for you. Your bodyweight, waist and daily steps sit next to it.
Free on iPhone and Apple Watch · No account · Coming to Android: join the waitlist
What weight loss needs from a workout app
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Strength training that keeps your muscle
Eating less makes some sessions feel heavy. If your reps drop but stay in the rep range, the weight holds and you aim for the same target next time. If a set falls below the range, the next set comes down a little. No weight goes up that your sets didn't earn.
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Sessions that fit the day
Short on time? Ask Coach to shorten today's workout or swap a machine. It shows the change as a preview, and nothing happens until you tap Apply changes.
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Cardio with a reason
Tell the app what your cardio is for and each session gets one timed bout paced for that reason. Lifting stays the main event.
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The scale, the tape and your steps
Log bodyweight, body fat and 13 body measurements, including waist and hips. A daily step goal sits on the Dashboard. When the scale stalls, a shrinking waist with steady lifts says the plan is working. More in am I gaining muscle or fat?.
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Apple Health and Apple Watch
Workouts finished on iPhone save to Apple Health, each exercise as its own segment. With an Apple Watch you can run the whole session from your wrist, rest timer included.
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Someone noticing you showed up
Add friends and they see when you train, cheer your workouts and share a weekly board against each person's own target. Reminders cover the rest: two days with nothing planned and the Dashboard offers to set a time.
Losing weight, session by session
Week 9 of a diet: the reps start to slip
Short Day 3 of four short gym sessions a week, most sets 1 rep short of failure. Down 9 lb, and the last set of each lift is getting harder.
| Exercise | You logged | Next session | Why |
|---|---|---|---|
| Bulgarian Split Squat | 30 lb pair, 11 / 10 / 9 reps per leg, 1 left (target 11) | 30 lb pair × 11 | The weakest set slipped to 9 but stayed in 8–12. Same weight, same target. |
| Seated Leg Curl | 80 lb, 12 / 10 / 9 reps, 1 left (target 12) | 80 lb × 12 | The last set dropped below 10–15, with no set after it. Between sessions that only holds: same weight, same target. |
| Dumbbell Lateral Raise | 15 lb, 20 / 20 / 20 reps, nothing left | 20 lb × 12–20 | Top of 12–20 at the planned effort, nine weeks into the diet: the next dumbbell. |
Slipping reps mid-diet cost you nothing on the bar. The weights hold, and some lifts still climb.
Twelve pounds down, and this week feels heavy
Three full-body days a week. Energy dips late in the week.
| Exercise | You logged | Next session | Why |
|---|---|---|---|
| Barbell Back Squat | 155 lb, 8 / 7 / 7 reps, 1 left (target 8) | 155 lb × 8 | The weakest set missed 8 but stayed in 6–10. Same weight, same target. |
| Lat Pulldown | Set 2: 120 lb, 7 reps, 0 left (target 10, 1 left) | Set 3: 110 lb | Seven is below the 8–12 range. 120 × 36 ÷ 40 is 108 lb, rounded to the stack's 110. |
| Incline Dumbbell Press | 35 lb pair, 12 / 12 / 12 reps, 1 left | 40 lb × 8–12 | Top of the range on every set. The next dumbbell up. |
A heavy week is logged as it happened. The next weights follow it, and nothing resets.
Back after a two-week trip
Two weeks without the gym. This is where people restart from scratch or quit.
| Exercise | You logged | Next session | Why |
|---|---|---|---|
| Romanian Deadlift | Last session: 115 lb, 10 / 10 / 9 reps, 2 left (target 9) | 115 lb × 10 | A skipped session changes nothing. You pick up at the weight and target you'd earned. |
| Dumbbell Shoulder Press | Last session: 25 lb pair, 12 / 12 / 12 reps, 1 left | 30 lb × 8–12 | That last session earned the next dumbbell, and it's still waiting. |
Under three weeks off, the plan just continues. Three weeks or more, it offers one easier week first.
Plans that open in RIRLift
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The best workout for full body, for your week
Short sessions, 4 days a week
The plan in the first example: four short gym sessions, mostly machines, rests kept as written.
4× a week · 60 sets a week · ~25 min
Add to RIRLiftSee the planAdd to RIRLift
Scan with your iPhone camera to add this plan.
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The best workout routine for the days you can train
3 days a week: full body
Three full-body days, each muscle trained every session. The plan in the second example.
3× a week · 51 sets a week · ~45 min
Add to RIRLiftSee the planAdd to RIRLift
Scan with your iPhone camera to add this plan.
Make it fit you
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Pick the Steady pace
In a calorie deficit, smaller steps are easier to keep. Steady takes them; switch to Standard when the diet ends.
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Set a step goal
Set a daily step goal and track it on the Dashboard, next to your training.
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Weigh in on a schedule
Log bodyweight a few mornings a week and your waist every couple of weeks, at the same time of day.
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Tell it what your cardio is for
Add cardio and say what it's for. Each session gets one timed bout paced for that reason.
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Train with someone
Invite a friend, even one without the app, or start a 7, 14 or 30-day challenge, head-to-head or as a team.
When a different app fits better
- You want calories and meals tracked. RIRLift tracks training, bodyweight, measurements and steps, not food. Pair it with a nutrition app.
- You want follow-along video classes or HIIT. A class or HIIT app fits better.
Questions
What is the best workout app for weight loss?
One built around strength training, since keeping muscle is what makes the weight you lose mostly fat. Pair it with a way to track food. RIRLift covers the training, bodyweight, measurements and steps, free.
Is lifting or cardio better for weight loss?
The diet does most of the losing. Lifting keeps your muscle while you lose, and cardio adds to the calories you burn. Two to four lifting sessions plus some walking or cardio covers both.
How many days a week should I lift to lose weight?
Two to four. Three full-body sessions is a simple start. The best workout for full body has a plan for two, three and four days.
Does RIRLift count calories?
No. It tracks training, bodyweight, body fat, measurements and steps. To estimate what a lifting session burns, use the calories burned lifting weights calculator.
Is RIRLift free?
Yes. Unlimited workouts, weight suggestions, the weekly muscle map and up to 4 active routines are free with no account. Pro adds more Coach conversations, unlimited routines and all-time analytics.
Read next
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The best workout for full body, for your week
The four-short-sessions plan in full, with every exercise demonstrated.
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Am I gaining muscle or fat? What the scale won't tell you
How to read the scale, the tape and your lifts together.
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Calories burned lifting weights calculator
What a lifting session burns, for your bodyweight and session length.
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How long to rest between sets, based on your goal
How short rests can get before they cost you reps.
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The best workout routine for the days you can train
The three-day full-body plan in full.
More ways lifters use RIRLift
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The body recomposition app that shows what the scale can't
Lifts that keep climbing at maintenance, with body fat and 13 measurements to prove the recomp is working.
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The workout app that puts your lifting in Apple Health
Lifting sessions saved to Apple Health exercise by exercise, next to your runs, with your next weights set.
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The full body workout app that knows what to lift each day
Full-body plans for 2, 3 or 4 days a week, with each lift's weight set from your last session.
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The workout app for women who want to get stronger
Lifting plans for glutes, legs and upper body, with the weight for every set picked from what you logged.