And for some (most) people they are fighting a huge uphill battle. An even slightly more efficient metabolism means if they eat the same as their peers who are

And for some (most) people they are fighting a huge uphill battle. An even slightly more efficient metabolism means if they eat the same as their peers who are in shape they will still gain weight. We need to recognize that caloric surplus and deficit is hugely impacted by deviations in many things that impact efficiencies (eg hormones, enzymes, etc…).