I'd read somewhere, long ago, that one of the main reasons that women gain weight after they get married is that they tend to eat the same sized portions of food as their husbands. Now, in general, men's appetites are a lot larger than women's appetites, and, somewhere along the line, if you lose track of that, you start eating a lot more than you actually need to and begin to bloat up. I had a hard time explaining this to my husband in the first couple of weeks of our marriage. My mother-in-law would serve me the same amount of food that she would serve him, and it was rather overwhelming for me. Now I've straightened things out with my husband and taken charge of the kitchen, so things are the way they should be.
This weekend, when I was visiting my uncle and his family, my aunt and I were talking about how much her elder son eats these days. He's on a 3500-calorie diet these days, because he's at an age where boys eat a lot and, on top of that, he's taken up a summer job with a landscaping company and carries rocks all day. Now I eat that much in about two days. So does his sister, who is two years older than he is.
My aunt told us this story about this woman who had seven daughters and no sons. One evening, one of her daughters brought her boyfriend home for dinner. Now the mother served everyone their regular portions of food, and the girls ate their fill and the boy, well, he ate too. Then the mother asked if people wanted to go out for a movie. The boy said, "Okay, but can we stop and get dinner on the way?"
I think my husband and his family had pretty much the same problem. He just has a brother, and no sisters. It was news to him that males and females have different appetites and that it is perfectly normal if I eat less than he does. I had to explain that men have more muscle mass, so their bodies burn more calories even when they are at rest. I had to hammer the idea into his head for a couple of weeks before it finally got across to him!