Rate-of-Change Targets

A rate-of-change target turns a vague goal ("lose weight," "bulk up") into a measurable weekly slope you can steer against. You compute the actual rate from the smoothed trend (this week's average minus last week's) and compare it to the target.

Common evidence-based targets:

• Fat loss: roughly 0.5–1% of bodyweight per week (for an 80 kg person, ~0.4–0.8 kg/wk), the range Helms et al. (2014) recommend for keeping muscle. In elite athletes, a 0.7%/week target added lean mass while a 1.4% target did not (Garthe et al. 2011). Clinical obesity guidelines quote 1–2 lb (0.5–0.9 kg) a week as an upper bound for adults with obesity (see Safe Rate of Caloric Deficit and Weight Loss).
• Muscle gain (lean bulk): much slower — about ~0.25–0.5% of bodyweight per week for novice and intermediate lifters, and slower still for advanced lifters (Iraki et al. 2019), since muscle accrues slowly and faster gain is mostly fat (see Setting Calorie Targets for Fat Loss, Maintenance, and Gain).
• Endurance/strength volume: progression rates (e.g. the "~10% per week" running-volume rule of thumb) are themselves rate-of-change targets, though that specific number is a guideline, not a law.

How to use it:

• Compare the smoothed actual rate to the target over a 2–3-week window (so noise has cleared — see Trend vs Noise).
• Too slow / stalled → tighten the lever (cut intake, add activity/volume).
• Too fast → ease off (risk of muscle loss, under-recovery, injury).
• This comparison is the trigger logic for program adjustments and the measurable core of a SMART goal.

Rates scale to the person (percent of bodyweight), so they generalize across sizes better than absolute kg/week figures.

• Target a weekly rate, then steer the smoothed trend toward it.
• Fat loss ≈ 0.5–1% bodyweight/week; faster risks muscle loss (Helms 2014; Garthe 2011).
• Lean muscle gain ≈ 0.25–0.5% bodyweight/week for novice/intermediate lifters; slower if advanced (Iraki 2019).
• Evaluate over a 2–3-week window so noise clears.
• Too slow → tighten the lever; too fast → ease off.