Bariatric surgery: risks and benefits explained

Rates of overweight and obesity continue to rise year by year, now effecting over 60% of Australian adults.  With this rise in weight, so too do rates of related diseases such as diabetes, cardiovascular diseases, respiratory dysfunction, infertility, depression and cancer also rise. Diet, physical activity and lifestyle changes are considered the fundamentals to weights loss, but what happens when they don’t work? In this article, dietitian Alexandria Hoare who works in the area of bariatric surgery explains the pros and cons of using surgery as a ‘last resort’ to control weight.

The NHMRC Clinical Practice Guidelines for Managing Overweight and Obesity released last year state that lifestyle changes were the least effective strategy for weight loss. It went onto explain that very few studies result in more than 10% loss of weight and weight loss is not likely to be maintained by most participants.  So when an obese person has tried diets, exercise, lifestyle interventions as well as pharmacotherapy without successfully losing and maintaining weight to improve health, what options do they have?

With the growing rates of obesity and related diseases, bariatric surgery is becoming a more widely sort after intervention. There has been a substantial increase in the number of weight loss surgeries performed in Australia from 500 in 1998-99 to 17,000 in 2007-08.

The most common bariatric (weight loss) procedures performed in Australia are:

Laproscopic Adjustable Gastric Band (known as a Lap-Band®): An inflatable silicone band is placed around the top of the stomach to produce a small pouch. The pouch holds a very small quantity of food and the band reduces the speed of the food entering the lower part of the stomach. As the pouch fills with food, it sends messages to the brain indicating that the stomach is full. This in turn produces the feeling of satiety and fullness which results in people consuming smaller portions of food.

Sleeve Gastrectomy: Around three quarters of the stomach is surgically removed, therefore reducing the quantity of food the stomach can hold. Levels of the hunger hormone grehlin which is produced in the stomach is also reduced resulting in people feeling full from a very small quantity of food. This is purely a restrictive procedure as the stomach is reduced in size however its function and digestion works normally.

Roux-En-Y Gastric Bypass: A small pouch is created from the upper stomach while the rest of the stomach is bypassed. Reconstruction of the gastrointestinal tract is performed which results in malabsorption of some food and nutrients. This is both a restrictive and malabsorptive procedure as the amount of food that the pouch can hold is reduced as well as reducing the absorption of food and nutrients which leads to weight loss.

All procedures can be done laproscopically (key hole) and each surgery has its own set of risks and benefits. The choice of surgery is very individualised as weight, urgency, comorbidities, family history, age and lifestyle factors are taken into account. The risks and benefits of each surgery must be

carefully considered so an informed decision can be made as to whether surgery is the right option.

Risks and side effects of surgery

Weight loss surgery is not a ‘quick fix’. The majority of people undergoing weight loss surgery have spent years, even decades, trying to lose weight. They have tried diets, meal replacements, pharmaceutical measures, hypnotherapy, exercise, calorie counting and resorted to bariatric surgery after exhausting all other options.

Surgery is not a quick fix, it is a lifelong process. It takes education, meal planning, daily supplements, behaviour changes and lifelong monitoring and checkups to ensure that optimal weight loss and health is achieved.

Any surgical procedure comes with risks and being obese makes those risks even greater. Surgical risks include leaks, haemorrhage, bowel obstruction and damage to adjacent organs. Whilst bariatric surgery is seen as the most effective weight loss strategy, there is the potential of weight regain after initial weight loss.

All procedures come with the risk of nutritional deficiencies especially for protein, iron, calcium and vitamin D. The recently updated ASMBS guidelines state that all bariatric surgeries can lead to nutritional deficiencies and patients must have lifelong supplementation. Loss of bone mass and increased risk of metabolic bone disease is a potential consequence of surgery with one study finding significant decreases in bone mineral density one year post gastric banding.

The surgery itself will control the amount of food one can consume, but it does not control the quality of food consumed. Following dietary advice is essential to maintain health and ongoing weight loss after the surgery.

If not adhering to correct nutritional advice and eating habits, people may experience nausea and vomiting, discomfort after meals and ‘dumping syndrome’. Body contouring to remove excess skin may be required for those who lose significant amounts of weight.

Benefits of bariatric surgery

Bariatric surgery is associated with significant weight loss and improvements in many obesity related diseases are well documented.

The NHMRC reports that bariatric surgery is the most effective weight loss intervention. A recent study of over 3200 Lap-Band® patients reported an average 47% excess weight loss maintained at 15 years.  Mean average excess weight loss at 10 years post gastric bypass has been reported as 57% and 55% at 5 years for sleeve gastrectomy.

In obese patients with type 2 diabetes, bariatric surgery is more effective at controlling blood sugar levels than standard diabetes treatments.

One study saw diabetes remission in 50% of bariatric patients at 6 years post op and diabetic control still improving 9 years after surgery. Diabetic nephropathy improved or stabilised following surgery,  as well as long term control of blood lipids and hypertension.

Significant improvements were observed 3 years post op for cardiovascular diseases, diabetes, obstructive pulmonary disease, respiratory diseases, diseases of the musculoskeletal system and mental disorders in a comprehensive analysis of over 5,500 obese people who underwent bariatric surgery . Medication use also significantly decreased for a number of conditions.

Bariatric patients have shown significantly better outcomes in social interactions, psychosocial functioning and depression compared to conventionally treated obese people at 10 years follow up.

Bariatric surgery may even have a ‘halo’ effect on family members.  According to one study, family members of patients who underwent Roux-en Y gastric bypass reported weight loss and improvements in their own lifestyle. One year after the surgery, other family members had increased their daily activity levels and their eating habits had improved with less uncontrollable eating, emotional eating and alcohol consumption.

Summary

Bariatric surgery is not a ‘cure for obesity’, it is a tool and it relies on the individual to adhere to lifestyle changes and commitments to achieve the best outcomes. It is not the first approach to weight loss and it is rarely the second or third either. Whether undergoing bariatric surgery or not, following a healthy diet and regular physical activity remains the cornerstone to optimising health and maintaining a healthy weight.

About Alex

Alex is an Accredited Practising Dietitian (APD) and nutritionist based in Melbourne with a Bachelor of Health Science and a Master of Dietetics from Deakin University. Alex is active in the social media space and you can read more of her health writing through her blog The Dietitian’s Pantry and connect with her through Twitter and her Facebook page.