Dear Scientist Friends:
Consider this a personal invitation to test a theory, especially if your area of expertise is endocrine and/or you have a personal interest in exercise physiology and weight management. (Er, and if you’re just one of my regular blog readers, please eaves drop on this letter.)
For several years, I have been synthesizing scientific information and personal experience as a radical weight-loss maintainer, and I would appreciate an experiment designed to better test the relationship between exercise and endocrine, especially those dicey signals that I believe cause most people to regain lost weight – the imbalance of leptin and ghrelin, PYY3-36 and aghouti related protein. If you know of an experiment that has already explored this relationship, then please provide me a link. (Disclaimer, as a lay person, my knowledge is embarrassingly limited. I have not yet read Katarina Borer’s book on Exercise Endocrinology, or any other scholarly text, so maybe I’m naive, but if we do know all that we could know on this topic, it sure hasn’t made it into the mainstream marketplace of ideas.)
It has occurred to me that there are different kinds of “hunger.” Those of us who maintain radical weight losses have pretty much mastered how to quell insulin-triggered hunger and vacuous (empty stomach) hunger using macronutrient management. In short, we use carbs (such as bananas or dark chocolate) to quell immediate, sharp (vacuous) hunger, and we use proteins and fats to keep sneaky insulin-triggered hunger at bay. But this is not the full story. If it were, more than 3% of people would be successful at maintaining radical weight loss for five years, the depressing figure that empirical research suggests.
According to the National Weight Control Registry (which could also be called the 3% Club), where I am listed as a participant, 90% of us exercise on average one hour per day. This finding is one of the most dramatic commonalities among us, more so than eating breakfast (78%), regular weighing (75%) or limiting our TV viewing (62%). In fact, the only two characteristics that are more common than the hour of exercise are that we have restricted our food (98%) and increased our exercise from our fat days (94%). (It should hardly come as a surprise that one hour daily represents an increase for most people!)
Learned people debate the value of exercise compared to food restriction in losing or maintaining weight, assuming that exercise is a function of energy balance – calories expended v. calories consumed. Energy balance, however, is not a simple equation, and I think exercise serves an additional, more important, function beyond expending energy. I think we need to know more about its effect on endocrine.
I have tried to wrap words around internal experiences that I call “eat impulses.” Examples of this wordplay may be found here, here and here, among other places on this blog. Perhaps I am disordered, but, clearly, my brain functions differently now, as a weight-reduced person. I am sensitive to these “eat impulses,” which are real and compelling but don’t feel like vacuous hunger or insulin-triggered hunger.
Culturally, this discrepancy between recognized hunger and endocrine impulses has created a significant problem. I believe that because “eat impulses” do not qualify as “hunger,” people feel guilty when they respond to them, and they feel enormously defeated when they regain weight as a result of responding to them. They don’t know why they can’t control their eating, so they blame themselves. They are unconsoled by the fact that 97% of people who lose weight will regain, just as they have. In fact, when they see others regain weight, they jump on the blame bandwagon because they know the dirty little secret: that people who regain weight eat when they aren’t “hungry.” A sad culture of fat humiliation has emerged in the developed world based on this misunderstanding. Regainers may NOT be “hungry,” technically, but they are impelled, powerfully, by endocrine.
People who maintain radical weight loss have quite a burden. They must defy a cultural mythology that suggests that “maintenance” after weight loss is more relaxed than loss itself and equivalent to what other people do who have never been fat. In fact, weight-reduced people must practice a much more challenging and restrictive regimen than people who have never been fat because they are metabolically compromised. Moreover, they must somehow quell the effects of elevated ghrelin, suppressed leptin and peptide YY3-36. Since no one has ever told them that taming endocrine is a requirement for weight-loss management, then whatever they are doing is something that they commonly do for other reasons. I put my money on that hour of exercise.
Before I close this letter, I would like to share what may be my only “inspirational” discovery during my weight-management saga. Prior to 2002, the year I began losing weight, I suffered frequent insomnia, probably 150 to 200 nights per year. My weight loss began when I added brisk walking (45 minutes) to my day and regular weight-lifting to my week. With that exercise, my insomnia also retreated. Walking was to become jogging and other intense aerobic exercise. I came to recognize that exercise was a gift I gave to my body.
One night my insomnia returned with a vengeance. I spent the whole night tossing, turning, sweating and tip-toeing at the edge of sleep. When the alarm went off, rather than remaing in bed, “Gawd, I need to rest,” I spoke a different script to myself. “Okay, body, just because I’ve deprived you a good night’s rest, I will not further punish you by denying you your exercise.” I dragged my weary carcass to the YMCA, punched my program into the treadmill and started to go. Within ten minutes, the woozy fog that engulfs sleep-deprived people had lifted. I felt normal. I completed my regular (vigorous) exercise. That day at work, I felt normal and I accomplished as much as I would on any other well-slept day. I also didn’t eat any more than I normally would. That night, I slept like a brick. It was glorious.
The relationship between sleep deprivation (A), ghrelin (B) and overeating (C) has been well documented. A + B leads to C. I would ask whether exercise deprivation (D) isn’t also a part of that equation and more important than A. Many people when they are sleep deprived may also be voluntarily exercise deprived.
I missed my calling to become a scientist, but I would cheerfully help in fundraising for a credentialed scientist who would set up and execute a study. Sadly, I’m not a millionaire myself and cannot fund this project, but I worked in nonprofit development for 15 years, and I can write grants. This would be one that would motivate me. Send inquiries to sappyarwood (at) att (dot) net.
Now, as for my regular blog readers, what’s your take on the relationship between exercise and weight management? Am I off base? Is it only a function of energy balance or is there something more? Do you have anecdotes?