April 20, 2010

Satiety and Problems with Obesity Research

There's plenty of research on obesity. When push comes to shove, however, we already know the answer. When we consume fewer calories than we use, we gain weight and vice versa.

There's much less research on what drives obesity: satiety. This is the feeling of being satisfied that you've had enough. So all the useless research on portion control, what a 4 ounce piece of steak looks like, on how to measure 100 grams of pasta, is of little applicable value. A patient put it perfectly, "I'm just not satisfied with a yogurt for lunch." We don't have a problem with metabolism, with not getting enough exercise, with fast food chains. If we could go to McDonald's and order one single hamburger and leave, we might be happy with the quality, taste, and value of the food. We don't do that for the same reasons we can't push away from the table after our 4 ounces of chicken breast.

For decades, stomach ulcers were thought to be caused by 'Type A' personalities, emotional instability, and so on. A whole medical-industrial industry had been created to get these high-strung, quick-tempered, hotheads to relax. It wasn't true. The ulcers are caused by a bacterial infection that is treatable. What everybody talks about as 'willpower' is a code word for blaming the patient in the same way that people with ulcers were blamed for their own ulcers. I have met people whose iron discipline is helpful in some circumstances; a surprising number of these folks, in my professional opinion, probably could be comfortable placed somewhere on the autistic spectrum. (You've met these people. Their diets aren't generally the only things they are completely rigid about. They often have difficulty imagining or accepting alternative ways of getting even simple tasks accomplished. Does this sound like people with easy-going personalities and excellent social skills?) For most of us, however, I think what we dismissively think of as a lack of willpower is, in fact, representative of deficiencies in our scientific knowledge about satiety. Many of us insist that our metabolisms run differently, and that others we see eating the same meals don't seem to have our difficulty with weight. I strongly suspect that what is unstudied is not differences of metabolic rate (sorry, most studies suggest that it's all about eating more calories than we burn). It's individual differences in satiety that determines if we need that extra piece of pizza.

When I lived in New York, I was taken to a screening of movies recently completed by film-school students, one of whom was the roommate of my girlfriend at the time. It seemed oddly curious to me that all the films had same maudlin themes of dark introspection. No humor, no irony, no twists, no surprises, no action, no sex. The roommate asked me what I thought. After saying that I thought it was really deep (she smiled proudly), I asked what kinds of movies she liked. She bragged, 'I've seen every European film produced in the last year that I could get my hands on.' I named a couple of blockbuster American hit movies and asked if she had seen any of these. 'Why would I?' she scoffed, and went back to a group of her classmates and professors in black turtlenecks.

It's not that the popular movies were better. But the fact that they were popular strongly suggests that there was some universal, shared appeal about them. So while I would never argue that one should eat more Big Macs, we miss something really important by ignoring how popular they are and why so many people really like them. This is the research that hasn't been done yet.

Back to the lousy student films. I would never argue that popular is equivalent to good. But only in figuring out why some things are popular can we find out our universal drives. Why isn't there more research about what makes fast food so good or so popular? Why do we like it so much, why do we eat too much of it, why do we want to get the larger size for just 50 cents more? Maybe there are great lessons to be learned there about the issues that the majority of us face every day in our eating decisions. This, I believe, is an important reason so many struggle with overweight.

This is also a reason why people on stimulant drugs lose weight. It's not that they no longer like cheeseburgers, or that the stimulant speeds up their metabolism. These medications reduce hunger and increase satiety.

Our bodies have no trouble losing weight. It's our brains that can't do it so easily.

So it has saddened me over the years to read so much research concentrating on the body, which was never the problem. Here are titles of 3 research studies in the April 2010 issue of Obesity, a leading medical research journal in this field:
  • Long-term Successful Weight Loss Improves Vascular Endothelial Function in Severely Obese Individuals
  • In Central Obesity, Weight Loss Restores Platelet Sensitivity to Nitric Oxide and Prostacyclin
  • Exercise Training Prevents Regain of Visceral Fat for 1 Year Following Weight Loss

So, based on these studies, weight loss is a good thing for the obese, especially if they start exercising. Imagine being sent a colorful postcard from a paradise-like exotic resort. It says that your friends are having a wonderful time, will probably never leave, and wish you were there. There's no mention about how to get there, how to afford it, or where, exactly, the place is.

With all of the above contributing to a comfortable amount of cynicism about this, I went to a lecture on childhood obesity. The content was an unexpected surprise. They didn't say that we're winning the war, not even winning the battle. But I think they've come up with some reasonable rudimentary tools. That's the next post.

1 comment:

  1. There is plenty of industry-guided research I'm sure on how to make things tasty (and inexpensive).


Please let me know what you think. Do you know a child or situation like this?