There is definitely a scientifically provable correlation between caloric intake and weight gain. It's somewhat causal in that if you suppress calories weight g

There is definitely a scientifically provable correlation between caloric intake and weight gain. It's somewhat causal in that if you suppress calories weight gain (growth) is reduced. The tricky part is that causality runs both ways. When a child grows, they take in a caloric surplus. If you surpress caloric intake, the growth will be suppressed. It's the same for plants too. Block the sun & they will grow slower. So (according to good/bad calorie theories) it's not that calorie accounting is incorrect. Take in fewer calories and you'll lose weight. It's that it misses the point. The correct question is why is your body growing (and pursuing the calories necessary to fuel it). *My own pet theory is that foods aren't inherently bad or unnatural for us to eat. We're just wired to build different bodies depending on available food sources. Mono-croppers need to survive bad harvests & hungry winters. Sugary fruits usually aren't available for very long, it might be good to build up a reserve while they are.