Some people can eat more than others for sure. If you are tall, very active, have high proportion of lean muscle to fat, young, and so on you need more food. If you are smaller, past the menopause, don't move much and tend to put on weight easily then you need less.
It's hard, but that's life.
You only put on weight if you eat more than your body needs. If you eat a little bit more than you need to, you'll put on a little extra weight. If you eat a lot more than your body needs, you'll put on a lot of weight.
So people who are overweight (unless they have a metabolic disorder) are, quite simply, eating more than their body needs in relation to their height, age, activity levels, etc.. You may not be eating all that much, but for you it is too much.