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Bariatric (weight-loss) surgery

Pokanga whakawhīroki

Weight-loss surgery is called bariatric surgery. It can be used for people who are very overweight and have not been able to control their weight through any other method.

If being very overweight is complicated by other medical conditions such as diabetes, obstructive sleep apnoea, reflux, polycystic ovary syndrome (PCOS) or heart problems, losing weight becomes even more important. Surgery may be an option if you have several significant health problems related to your weight.

Weight loss surgery is major surgery, and you should only consider it if trying to lose weight through healthy eating and physical activity fails.

The aim of the surgery is to control your hunger and your feeling of fullness after eating (satiety) to reduce your excess appetite for food. This works alongside good food choices to enable you to lose significant weight.

Types of bariatric surgery

Sleeve gastrectomy

Sleeve gastrectomy reduces the size of your stomach by surgically removing over 90% of it. The surgery turns it from a 2-litre bag into a 100 ml narrow tube. This is a permanent change that cannot be reversed. The average weight loss after this procedure is 60% of excess weight within nine months.

Gastric bypass

Gastric bypass involves bypassing much of your stomach only leaving about 30 ml and the first part of your small bowel. This means you cannot absorb as many calories. The average weight loss after this procedure is 70% of excess weight within nine months.

Gastric band

Gastric band surgery is no longer offered publicly or privately in the South Island. This is because of a high rate of repeat operations needed. The procedure involves placing a silicon band around the top of your stomach, reducing its size.

Weight loss is usually slower than with other types of surgery. Also, although it's reversible, people can develop complications. If you're having difficulty with your gastric band, see your general practice team to be referred to a surgeon.

Eligibility for publicly funded bariatric surgery

A limited number of people aged between 18 and 60 years are eligible for publicly funded weight loss surgery. Publicly funded means that the public health system pays for your surgery. Visiting your general practice team is the first step to see if you might be eligible.

Other criteria that you need to meet to qualify for consideration for publicly funded surgery include:

• a body mass index (BMI) greater than 40
• issues with being very overweight for longer than 5 years
• failed attempts at weight loss for more than 2 years
• ability to accept the requirement for long-term follow-up and dietary restriction.

Exclusions to having publicly funded surgery include:

• being a smoker
• severe heart or lung disease
• active cancer
• liver disease (cirrhosis or portal hypertension)
• Crohn's disease
• an eating disorder.

Because there is a limit on the number of publicly funded surgeries available, there is an assessment and selection system that your general practice team will discuss with you.

Public funding for these surgeries is shared across regions. Some patients selected for weight-loss surgery might have to travel elsewhere in the South Island for their surgery.

If you do not want to wait or you can afford to pay for your surgery, you may wish to look at having it done privately.

Surgical risks

Any surgical procedure has some risks. Your surgeon will talk through possible surgical risks with you and answer your questions.

Along with the more general short-term complications that can occur with any surgery, there are complications that can occur with bariatric surgery up to several years after having it done.

The complications depend on the type of bariatric surgery you have and can include a leak of stomach contents along a staple line, ulcers, internal hernias and vitamin deficiencies. The overall complication rate is about 4 to 6% with some of these needing further surgery. Your surgeon will explain these in more detail if you're having one of these surgeries done.

Before Surgery

Before surgery, most people will need to have a pre-surgery very low-calorie diet (VLCD) such as Optifast for at least two weeks. This is to temporary reduce the size of your liver and provide safer access for the surgeon. The pre-surgery diet also helps to prepare your body for dietary changes post-surgery. The bariatric dietitian will discuss this with you at your initial consultation.

After surgery

Bariatric surgery is most effective when it's combined with good food choices and a healthy lifestyle. Your bariatric dietician will guide you through the process. You'll achieve the best results if you follow these suggestions.

• Eat nutritious food, including protein-rich foods, fruit and vegetables and minimal added sugar and fat.
• Eat smaller quantities of food and chew it very well. This is sometimes called the 20:20:20 rule. Chew each mouthful 20 times, wait for the count of 20 between mouthfuls and no meal should last longer than 20 minutes.
• Do not graze between meals.
• Have at least 6 cups (1 ½ litres) of fluid per day. Drink between meals rather than with meals.
• Take up and maintain daily physical activity.
• Commit to long-term lifestyle changes and follow up, including annual nutritional blood tests.
• Take supplements such as a daily multi-vitamin-mineral supplement for the rest of your life.

Your bariatric dietitian will give you more information about food choices, portion sizes and so on. Bariatric plates and bowls can be useful.

It's also important that you take time to think about and address the things both physical and psychological that may have been part of the reason for putting weight on in the first place. If you think you need help with this, talk to your general practice team, psychologist, bariatric nurse specialist or weight-loss surgery team.

  HealthInfo recommends the following pages

• NHS:
  • Weight loss surgery
  • Recovering from weight loss surgery

    These pages have detailed information about weight-loss surgery and what happens afterwards. The criteria for weight-loss surgery only applies to the UK. See above for information about the criteria for weight-loss surgery in New Zealand.

Written by HealthInfo clinical advisers. Last reviewed August 2022.

Sources

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Review key: HIBAR-51647