Frequently asked questions & use cases

Carbohydrate calculations in RATIO do not rely on static empirical rules, but on actual metabolic energy expenditure derived from mechanical power and the percentage of sustained FTP. First, total caloric expenditure is calculated using the physical equivalence Expenditure (kcal/h) ≈ Average Power (W) × 3.6 (assuming gross mechanical efficiency of 21.8% to 24%). Next, based on the Crossover Concept by Brooks & Mercier, substrate partitioning is determined: at Zone 1-Zone 2 intensities (<65-75% FTP), the body primarily oxidizes fatty acids (30-50 g/h carbohydrate demand), whereas in Zone 3 Tempo (76-90% FTP) and Zone 4 Threshold (91-105% FTP), exogenous glucose demand rises to 60-90 g/h or up to 120 g/h using dual maltodextrin:fructose ratios (1:0.8) and gut training. Finally, the algorithm adjusts the output based on individual metabolic phenotype (Diesel vs. Puncher) and environment (1.12× indoor trainer factor).

Mechanical power (watts) is an objective, instantaneous external load metric unaffected by confounding factors such as psychological stress, lack of sleep, caffeine, or ambient temperature. In contrast, perceived exertion (RPE) and heart rate suffer from decoupling and cardiac drift, underestimating initial caloric expenditure and overestimating it toward the end of a session due to fatigue or dehydration. Planning intake based on real power output enables exact calculation of mechanical kilojoules performed, synchronizing glycogen and electrolyte replenishment before physiological depletion occurs.

After calculating your fueling plan, RATIO lets you download a file with your route and, if you choose, your fueling waypoints (where to take each gel, bottle, or solid) to import yourself into your bike computer — it's not an automatic sync with your Garmin or Wahoo account. 1) For Garmin Edge: download a GPX file (with fueling waypoints included if you check that option) and import it into Garmin Connect (Training & Planning > Courses) or sync it with your app. 2) For Wahoo ELEMNT: download a FIT file with the fueling waypoints already embedded, open it from your phone with the Wahoo ELEMNT Companion App, and sync it over Bluetooth.