There's a tangent at the top of this one — it's a good one — but once the fitness content kicks in, it's one of the more useful episodes we've done. Caleigh's Apple Watch got an update that started showing heart rate zones during walking workouts, and the data had some things to say.

Sara breaks down what zone 2 actually means: working but not struggling, breathing harder, still able to hold a conversation. And more importantly, what it actually takes to get there and stay there. Spoiler — it's more than most people are doing.

From there, it's a full breakdown of TDEE activity level multipliers, why most people rate themselves too high on the scale, and the rule Sara uses when running macro calculations for clients. Plus, why the incline on your treadmill is doing more work than you think — an ...