A few years ago my mum gave me my grandma's cookbook. I can't use it. Almost every recipe is crammed with sugar and butter. My grandma actually cooked from this cookbook for her family, and no one was overweight, even though they must have been eating more than 3000 calories a day, as far as I can tell. They had a farm and did lots of physical work. They must have walked the equivalent of several miles a day. There was very little sitting around except on Sundays.
I keep hearing people saying that we need to reduce our calories, but when I consider how my grandparents lived, the main difference seems to be that we eat a little bit less and are much much less active. So I'm not worried about sugar or fat in particular - I just don't see where I'd find the time to get as much exercise as my grandma.