Of course not. But one person could eat 10 kg of food and gain 5 lbs, while you eat 10 kg of food and gain 4 lbs all else being equal.
And yes, you can become overweight eating the same thing as someone else simply by having a more efficient metabolism. Unless you believe that there is absolutely no variation between humans, which would be ridiculous. All it takes is a 1% difference in BMR to amount to 25 excess pounds over a year's time all else being equal.
And yes, you can become overweight eating the same thing as someone else simply by having a more efficient metabolism. Unless you believe that there is absolutely no variation between humans, which would be ridiculous. All it takes is a 1% difference in BMR to amount to 25 excess pounds over a year's time all else being equal.