What happens when you get a surgeon to discuss the reasons people get fat? I expected her to focus on surgery as a cure, and that’s exactly what I got.
Let’s start from the top. According to the RadioTimes blurb about “Horizon: The Truth about Fat”:
Surgeon Gabriel Weston explores why so many people are piling on the pounds – and learns about new ways to fight the flab. She discovers the hidden hormones that control appetite and sees the latest surgery that fundamentally changes what a patient wants to eat – by altering how their brains work.
I watched the episode on the BBC iPlayer web site (episode found here, valid for 4 weeks only). It was a shallow examination of the complex reasons behind the obesity epidemic, that only hinted at some possible causes without much critical scrutiny.
Dr Weston kicks off the show by postulating that getting fat might not be a problem of willpower after all. This non-revelation should not be surprising to the millions of people around the world who have tried, and failed, to lose weight through conventional dieting and exercise.
A study cited in “Be Excellent at Anything” showed that “95% of those who lose weight on a diet regain it, and a significant percentage gain back more than they originally lose”.
Obviously, there has to be more to the story than just willpower.
So, Dr Weston looked at three areas in the show: hormones, twin studies and genetics, and gastric bypass surgery.
Firstly, Dr Weston zoomed in on the role of hormones in regulating our appetite. She fasted for 24 hours, and had regular blood samples taken. The level of her “hunger” hormone ghrelin plunged immediately after the meal, and gradually rose over the course of the day while her “fullness” hormones leptin and PPY did the opposite (click for further reading on appetite hormones).
However, in the case of an obese person, their appetite-regulating hormones stayed pretty much constant. This could help explain why overweight people have problems controlling how much they eat.
It is uncommon in science to see such a straightforward relationship. Disappointingly, Dr Weston did not follow up with the possibility that correlation does not mean causation. The appetite hormones could simply be a sign that there is a problem, but it does not mean that they are the cause.
2. Twin studies
Next up, twin studies – specifically monozygotic identical twin studies. Scientists love identical twins because both twins possess exactly the same DNA. Any differences observed in them must be attributed to the environment.
What makes one twin fat and the other skinny? Dr Weston didn’t answer the question directly.
Instead, she looked at the possible factors that affected how the genes were expressed. This is the field of epigenetics, defined in Wikipedia as “the study of heritable changes in gene expression or cellular phenotype caused by mechanisms other than changes in the underlying DNA“.
Intriguingly, the diets of pregnant mothers influence the weight of their children. For example, if the mother was malnourished during pregnancy, the baby appeared to receive the signal that it was born into a world where food was scarce. Its body became efficient at storing fat, and years later, the baby grows up into an obese adult, and because of what happened decades earlier.
The scientists estimated that some 25% of the variation between the twins’ weights could be explained by genetics.
But what about the other 75%? How about factors like lifestyle, exercise, and diet? Shouldn’t we be looking at the larger slice of the piece, and see what could be done about the things that we can control? Again, this was not discussed in the show.
3. Gastric bypass surgery
Dr Weston saved the best till last. There was some pretty gruesome footage of gastric bypass surgery. This is a drastic measure of last resort, only to be used by morbidly obese patients when all other methods have been attempted, and failed.
It’s astonishing how advanced the surgery has become. Surgeons no longer need to open up the patient’s body; the procedure could be performed through key-hole surgery for quick recovery and short downtime. In the show, one could see thick layers of visceral (abominal) fat over the patient’s stomach that has built up over the years.
In gastric bypass, as the name implies, the stomach is not removed, but instead made obselete. The surgeon simply severs the tubes leading to, and away from, the stomach, and connects them directly. Like an old town that is abandoned after a new highway bypasses it, the stomach is taken out of the equation. It effectively shrinks from the size of two fists to the equivalent of a thumb.
Amazing to watch.
But what about the risks and the costs of surgery? If this were a method of last resort, what other effective ways to lose weight are there? Again, this was omitted.
The fight against obesity is something that everyone could identify with. We all know a friend or family member who has struggled with weight problems, and at some point, we wished that we could do more to help.
Dr Weston gave us a glimpse into some intriguing topics but never explored them satisfactorily. The medical slant was perhaps inevitable, given her medical background, but I think viewers would appreciate more practical advice in such a personal and intimate issue.