Do not expect buying a fitness tracker to make you lose weight
A tracker does not supply the behavior change for you. In one two-year trial, people given a wearable lost less weight than people receiving the same lifestyle program without one.
What it takes
About RMB 200–2,000 for the device, plus the attention spent checking and managing its data.
What you may gain
IDEA enrolled 471 adults with overweight or obesity and followed them for 24 months. Both groups received a lifestyle intervention. The group using a wearable lost 3.5 kg (95% CI 2.6–4.5), compared with 5.9 kg (5.0–6.8) in the group without it. The difference was 2.4 kg (1.0–3.7; P=0.002), favoring the group without the wearable. The purchase feels productive because measuring activity seems equivalent to managing it, and a one-time purchase feels easier than changing a daily routine.
Context & considerations
This was one trial using an armband device from the early 2010s; it does not prove that every wearable is useless. Physical activity has benefits, as discussed in chapter 2. The point is that buying a device is not a necessary condition for exercising or losing weight.
Research & references
Jakicic JM et al. (2016). Effect of Wearable Technology Combined With a Lifestyle Intervention on Long-term Weight Loss: The IDEA Randomized Clinical Trial. JAMA. https://doi.org/10.1001/jama.2016.12858.