Why daily weight is misleading
One kilo more overnight is not one kilo of fat. If you ate more carbs or salt the day before, you retain water; after hard training the muscles hold water for repair; gut contents and cycle shift the number further. These fluctuations are often bigger than the change you are aiming for in a week. If you react to the bare number every morning, you are steering by noise.
What a trend weight app does differently
It blends each new reading with the previous ones. A single outlier shifts the line only a little, while a real change comes through over the days. The result is a calm curve from which you can read whether you are gaining, losing or maintaining, and how fast.
How Lean is law calculates the trend
- Exponential smoothing (default): each reading pulls the trend part of the way toward it, and older values slowly lose weight.
- Moving average over 7 or 14 days: simple mean of the last days, easy to follow but slower to react.
- Double exponential smoothing (Holt): smooths both value and direction, useful during steady gain or loss phases.
The weekly rate comes from a regression over the last 14 trend values. That way it doesn't jump with every daily value.
More than a line
In Lean is law the trend is the starting point for everything else: phases for Bulk, Cut, Maintain and Diet Break with rate evaluation, milestones, experiments with markers in the chart and, with Pro, forecast, plateau detection and adaptive TDEE. If you only want the trend, you can hide everything else: cards can be switched on and off and reordered.
Weight from Health
On iPhone, Lean is law reads your weight from Apple Health, on Android from Health Connect, in the background too. A smart scale that writes there therefore feeds the trend automatically. Older data from other apps you bring in via CSV import.