Seasonal Calorie Adjustment Methodology

Inputs and outputs

Formula

season = winter for Dec-Jan-Feb, summer for Jun-Jul-Aug, shoulder otherwise
winter: outside_only = +1.5% capped 20-60 kcal, all_day = +5% capped 80-140 kcal, day_and_night = +7.5% capped 120-220 kcal
summer: outside_only = -0.5% capped 10-30 kcal, all_day = -2.5% capped 40-90 kcal, day_and_night = -4% capped 70-140 kcal
adjustment = round_to_nearest_10(clamped(base_calories * rate))
adjusted_target = max(1200, base_calories + adjustment)

Calculation steps

1. Resolve the date into winter, summer, or shoulder season.
2. Use the matching exposure level only for that season.
3. Apply a small percentage adjustment with explicit minimum and maximum caps.
4. Round the adjustment to the nearest 10 kcal.
5. Do nothing in spring or autumn.

Guardrails

• The setting is optional and can be disabled.
• The adjustment is intentionally small because temperature response depends on clothing, indoor climate, acclimation, activity, appetite, and body composition.
• The final adjusted target is not allowed below 1200 kcal.

Sources

• Effect of acute cold exposure on energy metabolism and brown adipose tissue in humans Frontiers in Physiology
• Factors explaining seasonal variation in energy intake Frontiers in Nutrition