Wearables and weight loss: why more steps may not move the scale

Look at the support that follows the record

Antoun and colleagues separately examined studies combining an app, an activity tracker, and behavioral interventions. The between-group weight difference was −2.09 kg at 3 months, with a 95% confidence interval of −2.32 to −1.86 kg. At 6 months it was −3.77 kg, with a 95% confidence interval of −4.05 to −3.49 kg. The heterogeneity measures were 91% and 90%, respectively. These are findings for a combined intervention, not the amount of extra weight loss attributable solely to adding a watch.[3]

The eligible randomized controlled trials used a weight-loss app in at least one group. Weight change was measured from baseline to the 3- and 6-month points within each group, and those changes were then compared between groups and pooled. This distinction prevents a common misreading: a pooled difference between programs is not simply the amount every app user lost. It describes how weight changes compared under the conditions of the included studies.[3]

Combinations with intensive behavioral coaching or feedback from a human coach showed a difference of −2.03 kg at 3 months, with a 95% confidence interval of −2.80 to −1.26 kg. At 6 months, the difference was −2.63 kg, with a 95% confidence interval of −2.97 to −2.29 kg. Variation between studies was again substantial. The authors emphasized the human behavioral component when interpreting the stronger weight-loss results.[3]

The review also considered how differences in features related to app adherence and weight loss. Its separate analyses of app-based interventions overall and programs with accompanying support give readers a useful question: what is included alongside the app? That question applies whether you are choosing a new tool or reconsidering one already installed. A device may fit your daily routine, yet still provide a different kind of support from the program whose results caught your attention.[3]

In Li and colleagues’ 29-study review, frequently used behavior-change elements included self-monitoring, instructions on how to perform a behavior, feedback, goal setting, and action planning. Self-monitoring appeared in 25 studies, instructions in 24, and feedback in 20. These are descriptions of what an intervention helps a person do. They are not names for particular screen designs, and their presence should not be reduced to counting buttons or display panels.[12]

For example, a record might show that an evening of overtime left little opportunity to walk. An application of action planning would be to look at the routes and times that worked on other days, then choose an alternative for a busy day. This applies action planning and feedback to the move from recording activity to taking action.[12]

The same principle can guide how you assess reminders. What decision can you make when one arrives? Does it prompt a review of food choices, bring an activity plan back to mind, or provide material to discuss with someone offering support? Studies involving reminders, coaching, and feedback direct attention to these functions. Being able to explain when and how a record will be used is more useful than describing how busy the screen looks.[2][3][12]

An activity trial shows why long-term expectations need care

Yoshimura and colleagues’ trial assigned 55 participants to the app group and 54 to the comparison group. Both groups received a 1-hour lecture about weight loss and physical activity. Both were instructed to weigh themselves at least daily immediately after waking, and both received monthly advice emails. The app group was additionally told to check its step count and ranking at least once every day. Analysis followed the groups to which participants had been assigned.[11]

That shared support is central to interpreting the finding. The comparison was between common weight-loss and activity support with or without the added app-checking instruction. It was not a comparison between an app and doing nothing. The equal weight loss of 2.2 kg in each group therefore does not mean that nothing changed during the intervention. It means the extra app element did not produce a statistically significant additional weight-loss benefit in this trial.[11]

Before the intervention, average total steps were 7,259 per day in the app group and 8,243 in the comparison group. Physical activity was evaluated using an accelerometer, a device that measures movement. Because wearing time differed across the intervention periods, the researchers also analyzed steps per hour of wear and moderate-to-vigorous activity. The initial daily totals and the later hourly changes have different units, and should not be treated as interchangeable step counts.[11]

The before-and-after change was 65 steps per hour in the app group, with a 95% confidence interval of 30 to 101. It was −9 steps per hour in the comparison group, with a 95% confidence interval of −56 to 39. The between-group difference was significant. Analyses separating weekdays and weekends reported activity changes particularly on weekends in the app group. Yet the weight-loss difference was not significant. The trial does not establish why the extra activity failed to produce extra weight loss.[11]

For longer-term outcomes, Chew and colleagues’ 2022 systematic review and meta-analysis assessed trials in adults with overweight or obesity at different time points. Weight-loss effects were sustained from 3 to 12 months, but the amount peaked at 2.18 kg at 3 months and tapered to 1.63 kg at 12 months. The authors described the effects as small. Saying an effect persisted is different from saying that the amount of weight lost kept increasing throughout follow-up.[8]

Many interventions in that review extended beyond entering food into an app. They combined diet and exercise self-monitoring, personalized remote progress tracking, timely feedback, and devices that synchronized activity or weight data with a smartphone. Support for reviewing progress was part of the longer-term intervention. These features explain why a finding about sustained app-based weight loss should be read in the context of the accompanying program.[8]

The smartphone-only review highlighted limitations beyond 6 months, whereas the review including multiple components reported a small effect remaining through 12 months.[5][8] Those findings should shape expectations about what can be maintained. If you are deciding whether a purchase is worthwhile, consider whether the recording and support can still be used after the initial interest has passed. An early rise in steps answers an activity question; continued engagement and later weight outcomes require their own assessment.

Common misconceptions

“Wearing the watch will make weight come off automatically.” The umbrella review found benefits for both activity and weight, and its authors supported tracker use.[7] But the weight differences in programs combining apps, trackers, and behavioral support belong to the whole intervention.[3] The reported figures do not allow the contributions of those components to be casually reassigned to wearing a device alone. Look for the actual comparison before deciding what the finding promises.

“If I reach my step goal, my weight should move in the same direction.” In the 109-person trial, activity increased without a significant additional weight-loss benefit. The review in adults with overweight or obesity also found different results for activity, weight, and blood pressure.[6][11] Recognize walking as an activity outcome and assess weight separately. The scale is under no obligation to join the watch’s celebration. Keeping the two outcomes distinct allows you to acknowledge a real change without inventing another.

“An app with more features will produce more weight loss.” One analysis found no association between feature type or number and weight loss. Another found larger effects in interventions including reminders, self-reporting, or a coach.[2][3] These reviews collected and compared studies differently. They offer reasons to examine what support does, but do not establish a ranking based on the number of features. A clear plan for using feedback is a more defensible basis for a choice than a longer feature list.

What you can do today

• Choose a walking route and a time when you can use it, then take the walk at that planned time. Use a reminder as the cue to start walking, applying the action-planning approach used in the interventions.[2][12]
• Review food and physical activity together. After looking back at a food entry, decide what to change at your next meal and put it into practice alongside your planned walking. This applies the combined diet-and-activity approach identified as promising in the review.[12]
• Weigh yourself at least once daily immediately after waking, and keep the result separate from your step record so you can follow the two outcomes independently. When choosing an app, check how you can receive human advice or feedback on your records and connect with the available support.[3][11]
• Look beyond the changes at 4–6 months when assessing whether you can keep using the records and support. The smartphone-only review found limits to effectiveness beyond that period.[5]

From step tracking to a weekly practice at On the Shore Tachikawa

After reviewing activity on a screen, choosing where to move can help turn the record into a habit. On the Shore Tachikawa offers a place to keep that exercise habit going; consider the journey and the lessons you can attend alongside your daily schedule.

The lava-stone hot yoga studio is a 1-minute walk from the North Exit of JR Tachikawa Station, at 3F Etoile Bldg, 2-14-10 Akebonocho, Tachikawa, Tokyo. It is open every day 8:00–23:30.

Pregnant guests cannot join lava-stone hot yoga; room-temperature maternity yoga is available. Guests told by a doctor not to exercise cannot join. A trial yoga lesson costs ¥1,980, tax included, and includes a 60-minute lesson, 2 bath towels, 1 face towel, and mat rental. Details are on the studio website and prices page, with reservations through the trial booking page.

There are 25+ kinds of yoga lessons, alongside room-temperature yoga, Pilates, women-only kickboxercise, boxercise, HIIT, and personal training. Many of our yoga instructors speak English, and the studio’s owner often helps guests from the US bases in English herself.

References

1. Effectiveness of Wearable Trackers on Physical Activity in Healthy Adults: Systematic Review and Meta-Analysis of Randomized Controlled Trials — Matilda Swee Sun Tang et al., 2020, JMIR mHealth and uHealth. DOI: 10.2196/15576
2. Smartphone app-based interventions targeting physical activity for weight management: A meta-analysis of randomized controlled trials. — Hsin-Yen Yen et al., 2022, International journal of nursing studies. DOI: 10.1016/j.ijnurstu.2022.104384
3. The Effectiveness of Combining Nonmobile Interventions With the Use of Smartphone Apps With Various Features for Weight Loss: Systematic Review and Meta-analysis — Jumana Antoun et al., 2022, JMIR mHealth and uHealth. DOI: 10.2196/35479
4. The Role of Mobile Apps in Obesity Management: Systematic Review and Meta-Analysis — Carmelo Pujia et al., 2025, Journal of Medical Internet Research. DOI: 10.2196/66887
5. The Effect of Wearable and Smartphone Applications on Physical Activity, Quality of Life, and Cardiovascular Health Outcomes in Overweight/Obese Adults: A Systematic Review and Meta-analysis of Randomized Controlled Trials — E. Vosadi et al., 2022, Biological Research For Nursing. DOI: 10.1177/10998004221099556
6. Effectiveness of wearable activity trackers to increase physical activity and improve health: a systematic review of systematic reviews and meta-analyses. — Ty Ferguson et al., 2022, The Lancet. Digital health. DOI: 10.1016/s2589-7500(22)00111-x
7. Sustainability of Weight Loss Through Smartphone Apps: Systematic Review and Meta-analysis on Anthropometric, Metabolic, and Dietary Outcomes — H. J. Chew et al., 2022, Journal of Medical Internet Research. DOI: 10.2196/40141
8. Long-term Effects of the Use of a Step Count–Specific Smartphone App on Physical Activity and Weight Loss: Randomized Controlled Clinical Trial — E. Yoshimura et al., 2021, JMIR mHealth and uHealth. DOI: 10.2196/35628
9. Behavior Change Resources Used in Mobile App–Based Interventions Addressing Weight, Behavioral, and Metabolic Outcomes in Adults With Overweight and Obesity: Systematic Review and Meta-Analysis of Randomized Controlled Trials — Si-Jia Li et al., 2025, JMIR mHealth and uHealth. DOI: 10.2196/63313

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