It is easy to wear a device, log a meal, and pretend the graph agrees with whatever you already wanted to believe. The hard part is changing behavior after the graph quietly tells you that your habits are less special than your excuses.
Low carb can help. So can walking, sleeping, and not rewarding every stressful day with bad decisions dressed up as self-care.
The useful metric is not purity. It is whether the trend gets less stupid over time.