Reading this diary inspired me to gather my thoughts on this subject. This interests me because I struggled with overeating and morbid obesity; I reached my top weight of 320 pounds (size 52 pants; I am 6 feet tall) back in the winter of 1992.
I am at normal weight (188 +- 7 pounds or so) since 1995.
I'll talk about what I've learned through personal experience and through research.
More below the fold...
Diet (what we eat).
I found the following interview with an obesity researcher to be useful; here is the money quote:
Perhaps the most important illusion is the belief that a calorie is not a calorie but depends on how much carbohydrates a person eats. There is an inflexible law of physics — energy taken in must exactly equal the number of calories leaving the system when fat storage is unchanged. Calories leave the system when food is used to fuel the body. To lower fat content — reduce obesity — one must reduce calories taken in, or increase the output by increasing activity, or both. This is true whether calories come from pumpkins or peanuts or pâté de foie gras.
To believe otherwise is to believe we can find a really good perpetual motion machine to solve our energy problems. It won’t work, and neither will changing the source of calories permit us to disobey the laws of science.
Did you ever ask whether people respond differently to diets of different compositions?
Dr. Rudolph Leibel, now an obesity researcher at Columbia University, and I took people who were of normal weight and had them live in the hospital, where we diddled with the number of calories we fed them so we could keep their weights absolutely constant, which is no easy thing. This was done with liquid diets of exactly known calorie content.
We kept the number of calories constant, always giving them the amount that should keep them at precisely the same weight. But we wildly changed the proportions of fats and carbohydrates. Some had practically no carbohydrates, and some had practically no fat.
What happened? Did people unexpectedly gain or lose weight when they had the same amount of calories but in a diet of a different composition?
No. There was zero difference between high-fat and low-fat diets.
Note: the discussion centered on body fat and not things like water retention (which can bloat and cause large weight gain).
Physically, what we have going on is this: food is taken in; it has a caloric value. This is energy input.
Some of the energy is not absorbed by the body; it is just expelled. Of the energy that is absorbed, some is used for energy (daily activities) and the rest, if any, is stored. Period.
Of course, there is human variation in how much energy is assimilated by the body (made available for use and for storage). There is also some variation in how easily one stores excess energy; some people really do gain weight easier than others. And of course, there is variation on how easily people used their energy stores. Of course, different foods interact with different people in different ways as well. But ultimately, energy that isn't taken in can't be stored; all of us would starve to death if we didn't eat enough.
There is also human variation on how efficiently one uses energy. Some people have reptilian metabolisms and don't burn off that much. Also, getting more physically fit makes one use calories more efficiently; in fact this is a big part of what endurance sports training is about.
I completely understand that nutrition is about much more than weight; one can be overweight and undernourished (as many of our poor are) and that is a big political/moral issue. I also know that one can be thin and be in poor health too.
Of course, starvation level eating isn't good for anyone. There is some evidence that slightly undereating has some health benefits, but I don't know what to make of it.
Exercise
A quick glance at an calories per hour exercise chart shows that, unless one is an elite athlete, exercise doesn't burn off that many calories. This matches my personal experience; I found that when I was training for a very long footrace (24 hour event), all I needed to do to meet my training energy needs was to add one or two pieces of fruit per meal!
Still, exercise is good for you; however unless one has the personality that makes them love it (as I do), they probably won't stay with it. The non-addicted probably have to add other reasons to stick with exercise (e. g., make it part of one's socializing with others).
Most who start exercising say the goal is to lose weight or improve their health. But those who begin on the promise of imperceptible health effects often stop, Dr. Dishman said, saying they do not have time, or are too tired after work, or they just lost interest.
And there are no good studies investigating why people keep exercising. Dr. Dishman and others suspect the motivation is sheer pleasure — feeling energized, a boost in mood, feeling restless and uncomfortable without exercise. And you may not be able to will yourself to have this response.
Biological traits, Dr. Dishman says, “seem to play a bigger role in both the choice to be active and the outcomes of being active than folks — namely public health advocates— have been willing to admit.”
Dr. Dishman cites himself as an example of someone who craves exercise. Until about five years ago, he was an avid runner. Then his knee failed him — severe osteoarthritis — and he has not been able to run since. He still has dreams that he is running.
But instead of giving up on exercise, he rides a stationary bike simply because working out feels so good to him.
“If I can feel better after 30 minutes of riding in my office, alone, going nowhere, it has got to be something about exercise,” he said. But for him, as for many others, slow, moderate exercise does not bring the same physical pleasure. It must be hard exercise, meaning it has to require real effort, the sort of workout that makes people breathe hard and drip with sweat, Dr. Dishman says.
My story
Frankly, I got fat because I ate too much. Period. But stopping my overeating was impossible for me to do alone; I needed a support group. I still am with the group even though there are many times in my life when I just don't feel like going. I see it as my physical therapy.
As far as eating: I stick to eating at set times; I don't "snack". There are also certain foods I never eat, period. They set off cravings. There was a time in my life when I felt deprived at times, but those times have faded; now-a-days, I do NOT feel deprivation, at least the vast, vast majority of the time. I simply don't care about food all that much.
Note: I've had to adjust my diet (not temporary weight loss diet, but "diet" as in "what I eat") throughout the years; an active 52 year old needs less food than a 48 year old, who needs less food than a 44 year old...etc.
Also, I take the position that I have NOT "arrived" and never will. I treat my tendency to overeat and gain weight as an ongoing, chronic condition.
I have a "before" photo followed by some "after" ones; note that I chose general election years: 1992 (top weight), 1996 (normal weight), 2000, 2004, 2008 and 2012.
Yes, I enjoy running, distance walking and swimming (as sports). But when I lay off (illness or injury), I don't gain weight. I watch my weight so I can train; I never walk, run or swim any distance to allow myself to eat. That is a dangerous place for me to be in.
I've mostly chosen sports photos so you can see my body:
Me, in 1992
1996, at my wedding
2000, at the end of a 10K run.
2004, at the end of a 5K run (with a runny buddy)
2008, after a 5K open water swim. Yes, that was the official swim t-shirt and medal. This was in Chicago.
In 2012, at the finish of a 15K run.