Go to Settings › Metrics › Max carbs per hour (g). It starts at 120 g and goes from 30 to 210 g.

No plan asks for more than this in an hour, however hard the session. If you can't yet manage 90 g an hour, set 60 and raise it as your gut adapts.

Your limit also sets the colours on the Karoo and Garmin fields: a feed close to your per-feed maximum shows darker, so a big one stands out.

Profile shows your limit beside what you actually ate per hour.