Why is it so difficult to keep weight off?
Apparently, evolution has given us
the mechanisms to gain weight
but not to lose it.

BEFORE indulging over the Holidays, think about what Dr. Ayra Sharma, professor of medicine and chair of obesity research and management at the University of Alberta, Canada has to say about this issue.

How The Hedonic System Ratchets Up Your Weight

“Bill Colmers, the neuroscientist, presented an overview of how the brain affects eating behaviour and regulates body weight.

I was particularly impressed by how Colmers described the respective roles of the hedonic and homeostatic systems in human evolution.

While the hedonic (pleasure seeking) system evolved to help our hunter-gatherer ancestors seek out and take advantage of any highly palatable energy dense foods they happened to come upon, the homeostatic system evolved to protect from wasting away those extra calories that they did ingest.

Thus, according to Colmers, the hedonic system’s job was to make it hard to resist, in fact, make our ancestors to often go to considerable lengths to searching out those rare palatable energy dense foods and then to eat as much of them as possible, whether they were actually hungry or not. They could of course always store those extra calories as fat tissue for later use - a tremendous survival advantage.

In contrast, the job of the homeostatic system was to ‘defend’ those stored calories - in fact, it is designed to regard any accumulation of fat stores as the ‘new normal’ and from then on make sure that this increased level of fatness was maintained (or regained) ever after.

Indeed, the homeostatic system is ‘designed’ to readjust its set point of body weight - after all it has to do this starting from birth as body weight continues to increase as the baby grows into a toddler that grows into a kid and ultimately into an adult.

Unfortunately, the mechanisms that allow the set point to reset to ‘defend’ a progressively higher body weight - generally works in only one direction - after all that is all that is required by nature, where people do not naturally ’shrink’.

Colmers used the analogy of a ratchet to describe how the homeostatic system is designed to defend ever increasing body weights without having the ability to reset itself to a lower body weight even if the person now wants to lose weight.

Once set to a higher weight (e.g. resulting from ‘overindulgence’ driven by the hedonic system or other factors that may promote weight gain), the homeostatic system uses a wide range of mechanisms affecting hunger, satiety, appetite, metabolic rate, etc. to ‘defend’ this weight from then on.

A very helpful analogy I thought, n...

Recently the Stanford University Medical School, Health Policy Forum hosted an event examining the reasons why we get fat and how different diet trends and food policies affect our nation’s obesity rates.

The forum featured a conversation between science writer Gary Taubes and Christopher Gardner, PhD, director of Nutrition Studies at the Stanford Prevention Research Center.

During the discussion, Paul Costello, the medical school’s chief communications officer, talked to Taubes and Gardner about Americans’ misconceptions about food, diet and nutrition, the driving forces behind the obesity surge of the late-80s and the path to a healthier, leaner lifestyle.  Below is a video of that 1 hr 24 minute forum.

Regarding the article I recently posted:  The Fat Trap,  I am one of those people who believes that saying “weight-loss and maintenance is easy” is an unhelpful lie, and that telling people the Truth about weight-loss and maintenance is what is Helpful.

Below are a couple of follow-up questions and answers about the article that I think are worth posting at here at DietHobby.

Reader’s Question:
Were you at all worried that by writing a high-profile article about this research you would discourage people who are unhealthily overweight from trying to lose weight?

Answer from Auther, Tara Parker Pope:
I was really worried that the story would be discouraging to people, but I have been so pleased by the hundreds of e-mails and comments sent by readers. So many readers said to me, “Finally, my life made sense….” and “Now that I understand what’s happening, I’m really encouraged to try again…” One reader wrote that she found the article to be “sobering, challenging, and comforting all at the same time.” We don’t do dieters any favors by telling them that it’s easy and simple. I think telling people the truth about weight loss leaves them far better equipped to tackle the problem.

Reader’s Question:
A fascinating and disturbing part of this article is the section where you detail the extremely regimented lives of a few formerly obese people who have managed to keep off the weight. These rare individuals, as you quote a Yale scholar saying, “never don’t think about their weight.” A Slate article on your piece argues that the mentality of these people “resembles the symptoms of an eating disorder.” They suggested that our fat problem is not obesity but that we encourage people to adopt an eating-disorder mentality to fight obesity. How would you respond to this?

Answer from Auther, Tara Parker Pope
I think if a person had epilepsy and needed to adopt a very regimented diet to control that disease, nobody would accuse them of having an eating disorder. A person with high blood pressure might cut back on salt and take medication, and we don’t judge him. A person with Type 1 diabetes has to be very careful about what they eat and constantly monitor blood sugar to stay well. Again, we don’t question this behavior or call it disordered eating. But a person with obesity as a medical condition is ridiculed for gaining the weight in the first place and then they are criticized for being hypervigilant about maintaining a healthy weight. That said, I thought the Slate article made a good point, concluding “that a society that stigmatizes people for a physical attribute that they can’t change is the real fat trap we ought to be trying to escape.”

Research exists showing that a biological and metabolic backlash is triggered by weight-loss. 

Learning about the way our own biology operates to influence us with regard to food and weight issues helps make sense out of our dieting struggles, and provides a better understanding of the challenges that overweight / obese people face.

  Here is an excellent article that was published in the New York Times about that issue. 

The Fat Trap 
                    by Tara Parker-Pope -- The New York Times 12/28/11

For 15 years, Joseph Proietto has been helping people lose weight. When these obese patients arrive at his weight-loss clinic in Australia, they are determined to slim down. And most of the time, he says, they do just that, sticking to the clinic’s program and dropping excess pounds. But then, almost without exception, the weight begins to creep back. In a matter of months or years, the entire effort has come undone, and the patient is fat again. “It has always seemed strange to me,” says Proietto, who is a physician at the University of Melbourne. “These are people who are very motivated to lose weight, who achieve weight loss most of the time without too much trouble and yet, inevitably, gradually, they regain the weight.”

Anyone who has ever dieted knows that lost pounds often return, and most of us assume the reason is a lack of discipline or a failure of willpower. But Proietto suspected that there was more to it, and he decided to take a closer look at the biological state of the body after weight loss.

At that point, the 34 patients who remained stopped dieting and began working to maintain the new lower weight. Nutritionists counseled them in person and by phone, promoting regular exercise and urging them to eat more vegetables and less fat. But despite the effort, they slowly began to put on weight. After a year, the patients already had regained an average of 11 of the pounds they struggled so hard to lose. They also reported feeling far more hungry and preoccupied with food than before they lost the weight.

While researchers have known for decades that the body undergoes various metabolic and hormonal changes while it’s losing weight, the Australian team detected something new. A full year after significant weigh...