TRENDS

Trends

The Trends page is Fuel Lens’s time-series workspace. It lets you place nutrition and body measurements on a timeline, change the date window, compare up to five metrics, and inspect both the chart and the statistical summary below it.

Open Trends in Fuel Lens ↗

What the page can show

Trends combines two kinds of data in one metric selector:

Nutrients: recorded daily amounts such as Energy, protein, vitamins, minerals, and other nutrients available in the imported data.
Macro shares: Protein %, Net Carbs %, and Fat %. These are calculated from the recorded macro grams and Energy for each day. They are percentages, not gram amounts.
Ratios: configured ratio goals, such as macro or nutrient ratios. The selector marks these as ratios and the chart uses the ratio’s configured unit and target range.
Biometrics: imported measurements such as Weight and body-composition values, plus available exercise-calorie series. A biometric appears only when Fuel Lens has matching source data in the selected period.

The available list is data-dependent. A missing nutrient, measurement, or source field is left missing; Fuel Lens does not invent a value to fill the gap.

Select metrics

Use Select metrics to search the available catalog. Nutrients and biometrics are grouped separately, and some entries have a label explaining their type, such as Macro Share, Ratio, Goal, or DRI.

You can select up to five metrics. Each selected metric is shown as a colored chip with a matching chart line. Select the x on a chip to remove only that metric, or choose Clear all to reset the selection. The selected metrics and the aggregation choice are retained in this browser, so the page can reopen with the same analysis later.

One metric versus several

With one selected metric, Fuel Lens opens the detailed nutrient or biometric trend card. This view can add target context, an average line, and the metric-specific chart treatment.

With two to five selected metrics, Fuel Lens uses a shared comparison chart. Each metric gets its own colored axis so values with different units can be compared without pretending that they share a scale. The statistics for each metric are shown below the chart, followed by pairwise correlations when at least two series have dates in common.

Choose the date range

The sticky bar at the top of the app controls the active period for Trends. It is shared with the other dashboard views, so changing it changes which rows are available to the chart and the statistics.

Control	What it does
Week, 4 Weeks, Quarter, Semester, Year	Selects a preset duration ending at the current anchor date.
All Time / All	Includes the complete available history.
Previous and Next	Moves the selected window backward or forward.
Last day	Jumps the window to the latest nutrition date in the imported data.
Completed, Non-empty, All	Chooses whether the period is limited to completed days, days with data, or all days.
Calendar	Opens the calendar for more precise date selection.

The date shown in the center of the bar includes the selected start and end dates and, where available, the number of days with data. Always check this range before interpreting a trend or comparing two metrics.

Aggregation

The Aggregation selector controls how many source days are represented by each plotted point:

Choice	Meaning
Daily	One point per source day; no averaging is applied.
Week	Average values in seven-day blocks.
4 Weeks	Average values in 28-day blocks.
Quarter	Average values in 90-day blocks.
Semester	Average values in 182-day blocks.
Year	Average values in 365-day blocks.

The same aggregation is applied to every selected series in a multi-metric view. A block averages the valid numeric values that exist for that metric; missing values do not become zero. The plotted date for a block is the date of its last source point. Aggregation is useful for reducing day-to-day noise, but it also reduces the number of observations used by the statistics below.

Read the chart

The chart provides the following cues:

Colored lines: the selected metric series. Hover a point to inspect the value and date in the tooltip; the legend identifies each series.
Independent axes: in a multi-metric chart, each metric has its own axis, unit, color, and scale. This prevents grams, percentages, calories, and measurements from being mixed on one numeric scale.
Average: when an averaging window is active, the chart can show the corresponding averaged series or reference line. Daily mode is the unaggregated view.
Horizontal gridlines: the background lines align with rounded y-axis ticks and make values easier to estimate.
Target and DRI context: nutrient charts can display personal targets, recommended intake (DRI) values, and upper limits when those settings and reference values exist.

Nutrient targets and colored areas

For a nutrient with target information, the chart may contain both lines and background bands:

A blue DRI line marks the recommended minimum when it differs from the personal target.
A green Target line marks the personal target.
A white DRI/Target line is used when the two values are the same or only one effective target exists.
A red UL line marks the applicable upper limit.
Background bands indicate below-target, target, and above-limit regions when the relevant boundaries are available.

For ratio metrics, the chart can show separate Target Low and Target High lines. Macro-share charts use percent units and are calculated from the day’s recorded Energy, so a day without valid positive Energy cannot produce a macro-share value.

Statistics below the chart

The Statistics: [metric] card is calculated from the valid plotted points for that metric and the current date range/aggregation. Missing, non-numeric, or invalid dates are excluded. The card is hidden when no valid point exists.

Distribution statistics

Statistic	Meaning
Mean	Arithmetic average of all valid plotted values.
Median	Middle value after sorting the observations.
Standard Deviation	Typical spread around the mean. Fuel Lens uses the population form: variance is divided by the number of valid observations.
Min / Max	Smallest and largest valid plotted values.
80% Value Interval	The interpolated 10th-to-90th percentile range. It describes the central 80% of the observed values; it is not a medical reference interval.

These values describe the distribution in the selected view. If you change from Daily to Week or another aggregation, the number and values of the observations change, so the statistics change too.

Fuel Lens Trends view showing weight statistics across the selected date range

Change statistics

The second row describes the change from the first valid point in time to the last valid point:

Total change: last value minus first value, with the percentage change relative to the first value when that baseline is non-zero.
Average change / day: the endpoint change divided by elapsed days.
Average change / week, month, and year: the same endpoint slope scaled to seven days, 30.4375 days, and 365.25 days.

The rate cards appear only when the selected series spans enough time to make that rate meaningful: at least two days for a daily rate, 14 days for a weekly rate, 60 days for a monthly rate, and 730 days for a yearly rate. A positive value indicates an increase from the first point to the last; a negative value indicates a decrease. The percentage is omitted when the first value is zero.

Correlations in multi-metric views

When several metrics are selected, the Correlations section appears after the individual statistics cards. It contains one card for every metric pair with at least two dates where both metrics have valid values.

Covariance shows whether the two series tend to move together or in opposite directions. Its magnitude depends on the units of both metrics, so it is mainly useful for comparing the same pair under different selections.
Pearson coefficient is the unit-free correlation, ranging from -1 to 1 when it can be calculated. Positive values mean the two series tend to rise together, negative values mean one tends to rise as the other falls, and a value near zero means little linear relationship.
Shared values is the number of dates used for that pair. It can be lower than the total number of chart points because the two metrics may not have data on the same days.

Correlation is an association in the selected data, not proof that one metric causes the other. Date range, aggregation, logging completeness, and changing targets can all affect the result.

Pearson coefficient

The Pearson coefficient, usually written as r, measures the direction and strength of a linear relationship between two numeric series. In Fuel Lens it is calculated for each selected metric pair using only dates where both metrics have valid numeric values. The chart’s Shared values number is therefore the number of paired observations used for that coefficient.

Conceptually, the calculation is:

r = covariance(X, Y) / (standard deviation(X) × standard deviation(Y))

The result is unit-free and always lies between -1 and +1:

Value of `r`	Interpretation
+1	Perfect positive linear relationship: the two series move together in an exact straight-line pattern.
0	No detectable linear relationship in these paired observations. A curved or otherwise non-linear relationship can still exist.
-1	Perfect negative linear relationship: when one series increases, the other decreases in an exact straight-line pattern.
Between these values	The sign gives the direction; the distance from zero gives the strength of the linear association.

For example, r = 0.82 indicates a strong positive linear association in the selected data, while r = -0.65 indicates a moderately strong negative linear association. These descriptions are only rough guides: there is no universal cutoff for “weak” or “strong,” and the practical meaning depends on the metric pair, measurement quality, and number of shared observations.

What Pearson does not tell you

It does not prove causation. If Energy and Weight have a positive coefficient, that alone does not show that one causes the other.
It measures linear association only. A coefficient near zero can occur when the relationship is clearly curved, delayed, seasonal, or otherwise non-linear.
It is sensitive to outliers. One unusually large or small paired value can noticeably change r.
It depends on the selected data. Changing the date range, aggregation, day filter, or imported records can change both the coefficient and the number of shared values.
It is not a clinical threshold. A high or low coefficient is not a diagnosis, a health-risk score, or proof that a target has been met.

Fuel Lens displays N/A when the paired series do not have enough valid observations or when one series has no variation. With no variation, a standard deviation would be zero, so a Pearson coefficient cannot be defined.

A practical reading workflow

Set the date range and day filter in the top bar, then confirm the dates shown in the center.
Choose one metric first to understand its unit, target lines, and missing days.
Switch between Daily and a longer aggregation when you need either day-to-day detail or a smoother long-term signal.
Add related metrics—such as Energy and Protein % or Weight and Energy—to compare them on the shared chart.
Read the statistics as a description of this selected slice of data, and use the shared-value count before drawing conclusions from a correlation.

Trends are descriptive analysis. They reflect the quality, completeness, and definitions of the imported diary and biometric data; they are not medical diagnosis or proof of causation.

Interpreting associations

Correlations in Fuel Lens describe whether two recorded series move together in the selected data. They do not show that one metric caused a change in the other. Trends can also reflect missing records, changing routines, seasonality, or other factors not represented in the chart. Treat a correlation as a prompt for a question, not as a causal or clinical conclusion.

CDC, Field Epidemiology Manual. Analyzing and Interpreting Data explains why statistical association alone does not establish cause and effect.

Continue with these connected Fuel Lens guides.