> I don't buy it, no brand can be accurate on energy expenditure because it depends on a lot more things than what the watch can monitor. You could say the sam

> I don't buy it, no brand can be accurate on energy expenditure because it depends on a lot more things than what the watch can monitor. You could say the same about virtually every modeling problem, yet the world runs on models that work adequately in practice. You measure what you can, infer what you can, and fill in the gaps with priors.