I suspect something is wrong with our food, as well as our habits of living.
Reading my father's journals from 1959 to 1970, I noticed in particular something about our eating habits: we ate dessert three times a day. We had lunch dessert, dinner dessert, and bedtime dessert. I remember trying hard to convince my parents that we should logically have breakfast dessert as well, but was overruled. Probably because breakfast in those days was all too often sweet enough to be dessert in itself. True, we didn't have pre-sweetened cereal, but we had sugar in a bowl on the table....
And yet we were not overweight, much less obese. Not thin, but a healthy weight. Moreover, not one of us ever worked out at a gym or had any kind of regular exercise program. Ordinary living kept us in decent shape. My father was an engineer with a desk job; my mother a homemaker.
What made the difference? I can only guess.
I'm convinced that our food was both healthier and tastier. After all, I am older than McDonald's. Milk from a local dairy was delivered in glass bottles to our front porch; it was pasteurized, but not homogenized. Meat came from local butchers; I liked it best from the Jewish butcher, because then I was allowed to nibble on the raw ground beef, as we knew it had not been in contact with any pork products. (Pork was an exception to "food was healthier back then"; trichinosis was still a big problem, caused by pigs being fed raw pork, or so I was told.)
We didn't have farmers' markets back then; what we had instead was nearby farms that sold some of their produce at stands along the road. Their fruits and vegetables were only available in season, but they sure were fresh, and clearly superior to what the grocery stores sold. Our food didn't have nearly the variety we have today, but it was enough, and it was good. There's a blessing in being able to have access to food flown in from halfway across the world, and ethnic restaurants on every corner, but overall, thanks to agricultural mass production, it doesn't have the flavor it once had.
Consciously or unconsciously, we undoubtedly eat more quantity in an effort to make up for lost quality.
The other big difference that I remember in our food is portion size. At home, we always had plenty to eat, but common sense, both nutritionally and financially, kept the portions quite a bit smaller than is common today, even at home. And restaurant portions are ridiculous now! When I was growing up, restaurant meals were very rare occasions, and fast food almost non-existent. Even in restaurants the portions were much smaller than today. I had my first McDonald's hamburger during college; it cost 23 cents and, if memory serves, was half the size of a quarter-pounder today.
One thing we didn't do much of was snacking. Except for a small bit of milk-and-cookies after school, which was primarily valuable for the debriefing/decompressing time spent in the kitchen while my mother prepared dinner, eating between meals was considered unnecessary and even unhealthy.
Did I mention that we mostly ate at home? The food itself was largely home-prepared. Store-bought cookies, box cake mixes, pre-prepared salads, frozen meals—all either non-existent or considered far inferior to homemade. (Exception: Girl Scout cookies.) [Update: Thanks to Porter for catching my egregious misstatement, as I had orginally written "superior"! Not, I assure you, a Freudian slip.]
Then there was exercise. If there were fitness establishments, I never saw one. Gym class in school was for fun, not fitness: tumbling, marching, and playing games (including dodge ball) where winning was not of primary importance. There were no formal team sports that I remember before high school, though pick-up games of all sorts were common in our neighborhood, which abounded with playmates of all ages. Winter or summer, we were outside and active. Avid bookworm that I was, I still spent much of my spare time outside, either playing with my friends or wandering the fields and woods near our house. As I said, my father had a sedentary job, but walked for transport when he could (sometimes wearing snowshoes in the winter), played games in the yard with us and the neighborhood kids who congregated in our yard, and—though not as often as he would have liked—took us hiking in his beloved Adirondack mountains. There was also a good place to swim that was only an eight-minute drive from home, so you can bet that in those days without air conditioning swimming was a frequent summertime activity. Plus, he and my mother (occasionally helped by us kids), spent a lot of time gardening. Not farming, just ordinary suburban gardening, but everything was done by hand. Sawing wood, digging holes, planting bushes, roses, flowers, and even the occasionable vegetables, though the latter were much more efficiently obtained directly from the farms. Then there was mowing the lawn: keep in mind that this is what our lawn mower looked like:
I don't mean to imply that our situation was ideal. We were in a time of transition, and definitely headed in an unhealthy direction, but we were not all the way there yet when I was young. Both society at large, and the medical profession in particular, had already given up on breastfeeding and thought bottle-feeding with a concoction of sterilized water, evaporated milk, and corn syrup was the superior way to go. Someone with more financial sense than taste buds then introduced our generation to the instant orange-flavored drink known as Tang, and as a teenager I downed Carnation Instant Breakfast before going off to school. Unbelievably, these abominations still exist today.
But for a while, in my childhood, we ate nutritious foods full of natural natural flavors, and spent a lot of active time outdoors (without sunscreen). We even survived having regular bedtime dessert.
I walked to school from Kindergarten through grade 9. And in elementary school, we went home for lunch and then back to school. I also walked to Girl Scouts, piano lessons, etc. My father walked to work (about a mile) unless the weather was horrible, and sometimes came home for lunch, so he also walked it 4 times a day.