Why I Support Bariatric Surgery (Part 5)

Bariatric Food Pyramid

Bariatric Food Pyramid

Yesterday’s post was a brief overview of how bariatric surgery works and why it helps most people sustain weight loss by affecting key determinants of ingestive behaviour (hunger, appetite, satiety, reward, etc.).

Today, however, I want to look at why surgery is anything but a ‘quick fix’ or an ‘easy way out’ and why, despite all of its potential benefits on quality of life, comorbidities and mortality, surgery is by no means a ‘guarantee’ for success.

While ‘success’ with bariatric surgery is certainly not guaranteed (and for some patients, as with any drastic treatment, things can sometimes go horribly wrong), most patients do remarkably well, including – and this may surprise readers – patients with emotional eating or eating disorders.

Thus, as presented by Tom Wadden, Professor of Psychology, University of Pennsylvania School of Medicine, at the 18th European Congress of Obesity, which I am currently attending in Istanbul, Turkey, even patients with classical ‘Binge-Eating Disorder’ (BED) surprisingly benefit from surgery (OBESITY).

In this prospective case-control comparison of cognitive behavioural therapy, lifestyle intervention and the use of meal relacements vs. bariatric surgery in patients diagnosed with BED, the surgical patients did twice as well as the ‘lifestyle’ group  in terms of weight loss with significant improvements in cardiovascular risk factors.

Perhaps, even more importantly, the frequency of binge episodes dropped as dramatically in the surgical BED patients as in the non-surgical BED patients. Although the study published only one-year results, Wadden reported that even extended follow-up appears to confirm these results. Similar results have been reported by others.

I only bring up these studies, as it is widely assumed that because bariatric surgery does not address the psychological drivers of overeating (as the surgery is on the gut and not the brain), it may be far less effective or even futile in patients with severe eating disorders.

This is not to say that failure rates may be somewhat higher in people who are more predisposed to emotional eating or eating disorders – but on average, these patients appear do just as well.

So how can these findings be explained?

One reason may well be that although bariatric surgery primarily affects the homeostatic system of hunger and satiety, it indirectly also affects the hedonic system.

As regular readers may recall, hunger can markedly activate the hedonic (reward-seeking) centres of the brain, which I have previously described as the reason why “hunger makes you eat crap“. Thus, experiments, in which volunteers were given ghrelin (the hunger hormone), not only reported increased hunger, but also had increased neuronal activity in the reward centres of the brain.

This (indirect?) role of ghrelin in ’emotional’ or ‘hedonic’ eating behaviour may explain why BED patients and emotional eaters do better after sleeve gastrectomies or bypass operations than with gastric banding – the former reduces ghrelin levels, the latter increases them.

This discussion should make it clear that bariatric surgery is not simply about creating an ‘obstruction’ (as suggested by the terms ‘banding’ or ‘stapling’) but actually induces quite intricate and complex neuronal and hormonal changes in the gut-brain axis that determines ingestive behaviour.

Despite these changes, bariatric surgery is certainly neither a ‘magic bullet’ nor a ‘quick fix’.

Indeed, to be successful, patients have to make substantial and long-term changes in their lifestyles to get the maximum benefit of surgery. Even though the positive effects of surgery on hunger, satiety and appetite make it substantially easier for patients to sustain a rather low caloric intake (usually only about 1400 KCal) without experiencing constant hunger or cravings, patients do have to follow rather strict dietary recommendations (that can vary according to the type of surgery).

One obvious reason that bariatric patients have to substantially change their diet after surgery, is due to the simple fact that anyone, who eats only 1400 KCal per day, will have to eat a much more balanced and nutrient-rich diet to fully meet daily energy, macro- and micronutrient requirements than someone eating 2000 or 3000 KCal. The lower the quantity of food you eat – the greater the quality has to be!

In fact, this would apply to ANYONE trying to live off 1400 KCal, irrespective of whether or not this person has had surgery or not.

Eating as little as 1400 KCal (or less), without careful attention to adequate nutrient intake, carries the inherent risk of severe malnutrition that can include all the typical symptoms of ‘starvation diets’ including vitamin and mineral deficiencies that can result in anemia, hairloss, osteopenia, nerve damage, memory loss, lack of energy, and in the case of severe protein malnutrition, even sypmpoms of Kwashiorkor.

The point here, is that there is nothing specific about these symptoms to bariatric surgery, even if the risk for such deficiencies may well be higher in surgical patients, who do not follow the nutritional recommendations.

It may also be important to note that one reason why severe deficiencies are perhaps more often seen insurgical patients, than say in someone who goes on the cabbage-soup diet, is due to the simple reason that without surgery, patients would find it very difficult to stick to such a low caloric intake long enough to develop severe deficiencies.

Indeed, ensuring that a 1400 KCal diet meets all of the body’s protein, vitamin and mineral needs can be challenging for anyone – and even non-surgical patients on such a low caloric intake may need protein, vitamin and/or mineral supplements.

Thus, some of the commonly described nutritional deficiencies seen in patients with bariatric surgery, have little to do with the surgery itself, but rather with the fact that any such drastic reduction in food intake makes it far more challenging to meet the daily nutrient requirements. For this reason, simply eating less of an otherwise crappy diet will not work and will ultimately result in marked deficiencies.

Remember, patients with gastric banding and sleeve gastrectomies do not develop any maldigestion as their small bowel is left completely intact – so nutritional deficiencies in these patients cannot be explained by any maldigestion or malabsorbtion after surgery but rather result simply from the fact that these patients are now eating substantially less than before and therefore need to eat a much healthier and nutritionally sound diet than prior to surgery.

On the other hand, because bypass surgery does involve a maldigestive component, these patients  do have to be even more ‘obsessed’ about meeting their nutritional needs and may indeed have to resort to regular protein and/or nutritional supplements.

Fortunately, however, the types of nutritional deficits in these patients are largely well understood and proper assessment and supplementation will avoid nutritional deficiencies in the vast majority of patients if they follow the nutritional guidelines. Indeed, regular readers may recall the previous post on the bariatric-surgery food pyramid that clearly lays out the need for dietary changes.

Thus, the idea that undergoing bariatric surgery would allow someone to simply eat less of the same diet as before will not work – indeed, most patients will need to make considerable changes to their diets – not just in quantity (that part is easy after surgery) but particularly in quality – there is simply no longer any room for nutrient-poor foods (or for that matter liquid calories, which would simply defeat the whole purpose of having surgery in the first place).

But nutritional recommendations after surgery are not just limited to quality of the diet. There is an other important aspect of eating that bariatric surgical patients have to follow: meal planning and regular eating.

This is not difficult to explain. Normally, most people can easily skip a meal or two – or even go several days without food. For e.g. during Ramadan, devout muslims will go all day without eating, only to feast after sunset. This is possible when you have a stomach the size of a small football – in fact, this is exactly why the size of the stomach is what it is – to fill up on food, when food is available (or allowed).

This, however, is no longer possible after bariatric surgery. When the capacity of the food that can be eaten at a single meal is reduced to a few ounces, gorging or overeating is no longer possible (and will often result in vomiting – which only makes things worse). This means that patients, who have had surgery, can no longer afford to skip a meal and simply eat twice the amount at the next one. A missed meal – unfortunately remains missed!

Put this in the context of the need to maximise nutrient content of each meal and things get even more difficult. Thus, even if a bariatric patient instead of skipping a meal, simply eats a rather ‘un-nutritionous’ meal (say for lunch), the next meal would need to be even more nutritionous if the patient is to meet her daily requirements. This can be challenging even at the best of times.

This alone, should make it clear that avoiding nuritional deficiencies after surgery requires considerable planning and optimisation of food intake. Skipping meals or eating nutrient-poor foods is no longer an option. Patients, who do not understand this or cannot adhere to such dietary recommendations will need to take supplements – people who do not stick to these recommendation and refuse to take supplements will inevitably develop serious nutritional problems.

Unfortunately, as discussed in previous posts, many bariatric patients start out with pre-existing nutritional deficiencies that should be corrected prior to surgery, which is why we invest so much effort into getting our patients eating healthier even before consideration for surgery. Patients, who are unable to eat healthy balanced diets, will find it hard to do so after surgery and will be far more likely to develop nutritional complications.

None of this is ‘rocket science’ or in anyway ‘mysterious’ or in anyway specific to bariatric surgery (similar rules apply to all patients who may be restricting their nutritional intake for other reasons or have undergone gut surgery for reasons other than obesity.

Thus, one of the prerequisites for surgery in our program is that patients demonstrate both their understanding and ability to adhere to regular eating patterns (absolutely essential after surgery) and improving the nutritional quality of their diets (even more important).

It should therefore not come as a surprise, that from a dietary perspective, surgery is clearly not the ‘easy way out’ or in any way a ‘quick fix’. The notion that you can simply have your stomach ‘banded’ or ‘stapled’ or your gut rerouted and not have to also very substantially change your diet is nonsense and short sighted.

Remember, as quantity decreases, quality has to increase!

Fortunately, regular use of dietary protein, vitamin and mineral supplements can make this somewhat easier.

So while changing both nutrition quality and pattern are certainly important aspects of post-surgical management, other issues can be as, if not more, important determinants of success.

More on these, perhaps lesser known, aspects of bariatric surgery, which can often make all the difference between failure and success, in next week’s posts.

Istanbul, Turkey

Wadden TA, Faulconbridge LF, Jones-Corneille LR, Sarwer DB, Fabricatore AN, Thomas JG, Wilson GT, Alexander MG, Pulcini ME, Webb VL, & Williams NN (2011). Binge eating disorder and the outcome of bariatric surgery at one year: a prospective, observational study. Obesity (Silver Spring, Md.), 19 (6), 1220-8 PMID: 21253005

Bocchieri-Ricciardi LE, Chen EY, Munoz D, Fischer S, Dymek-Valentine M, Alverdy JC, & le Grange D (2006). Pre-surgery binge eating status: effect on eating behavior and weight outcome after gastric bypass. Obesity surgery, 16 (9), 1198-204 PMID: 16989704