Hey Product Hunt, In 2014 a pair of researchers asked a simple question of doctors, dietitians and personal trainers: when a person loses fat, where does it physically go? Most of them got it wrong. The common answer was that it turns into energy, or heat. Mass doesn't work that way - it has to go somewhere. It leaves as carbon dioxide, through your lungs. Lose 10kg and 8.4kg of it walks out as breath. What stayed with me wasn't the answer. It was who got it wrong. These were the people the rest of us ask. That is roughly the state of fitness knowledge. Claims circulate for decades without anyone checking them, because they sound mechanical enough to be true. Lactic acid is why you're sore tomorrow - settled as wrong in the 1980s, since blood lactate is back to baseline within an hour while soreness peaks at 24 to 72 hours. Unused muscle turns to fat - two entirely separate tissues, neither of which can become the other. Fat doesn't start burning until twenty minutes in - there is no switch, and the fat share of your fuel is actually highest while you sit still. Workout Trivia Quiz is 150 questions built the other way around: source first, question second. WHAT IT ACTUALLY DOES FOR YOU You open it on the train, tap a set, and five questions later you know something you can check yourself. Not a lecture - a three-choice question, then the explanation that tells you how we know. Every answer traces to a source. Each of the 150 questions was written from a cited claim - the BMJ paper above, a pooled review of 83 studies, a governing body's rulebook - not from what the internet agrees on. What isn't settled, stays unsettled. "Muscle grows by being damaged and repaired" is currently contested, with rebuttal letters published and no resolution. So the correct answer to that question is that it's contested. Some questions are about the fact that we don't know yet. It gets out of your way. Free. No subscription. No account. Works with no signal, in 16 languages. Your progress stays on your phone. WHY I THINK THIS MATTERS Fitness runs on an assumption nobody states out loud: that if a claim survives long enough in the gym, somebody has checked it. The fat study suggests otherwise - if the specialists hadn't checked, nobody downstream was going to. There is no peer review in a training partner, and the claims that spread best are the ones that sound mechanical. A plausible mechanism gets treated as evidence. What surprised me while building this wasn't how much was wrong. It was how much was genuinely unresolved, and how uncomfortable that felt to leave alone. I kept wanting to pick a side so the question would have a clean answer. Writing "we don't know" into a quiz app felt like a failure until I realised it was the only honest option. Two things I'd like to ask you: What's one training claim you repeat that you've never actually checked? I'll run down the good ones and add them to the question set - with the source, whichever way it lands. And: do you think the sourcing problem in fitness is genuinely worse than in other fields, or am I overstating it because it's the one I happen to be in?

Workout Trivia Quiz

Gym trivia, sourced. No broscience, offline, 16 languages

Gym trivia, sourced. No broscience, offline, 16 languages