I find threads like this fascinating - I am not sure what conclusions you can draw OP there is such a huge variety in diets, eating patterns and sizes!
I'm very nearly 50, 5ft6 and weigh 8 stone. I reckon I've lost half a stone over the past year - which is when I started running regularly - even though I feel like my portion sizes have all gone up. I am active (and always have been, only the running is new in the last year). I have a quite physical job, walk the dogs an hour a day, yoga 3 or 4 times a week, and run 4 times a week.
Breakfast - bircher muesli with grated apple, homemade granola, plain (whole fat) live yoghurt, and either banana or berries. Its a big bowlful.
lunch - normally two rounds of sandwiches on wholegrain (say tuna or salmon and absolutely stuffed with lettuce, salad, alfalfa sprouts, grated carrot etc)
dinner - tonight we're having marinated chicken which I'll griddle, with new potatoes and either a salad or vegetables.
I drink several cups of tea, and only use full fat milk. I use olive oil or butter for cooking (no low fat substitutes here).
If I've had a really hard run in the morning I might have a a piece of toast with peanut butter when I get back,or some salmon if I have some cold in the fridge, or just a couple of hard boiled eggs. I crave protein then!
Apart from the exercise/ activity I think my diet is very heavy on vegetables & fruit (I reckon on an average day I'll have 7 or 8 portions) which is filling so I don't get hungry between meals, apart from after running. And I don't drink alcohol.