Weight loss surgery explained

by | Diet and Weightloss, You ask we answer

Dr Georgia Rigas

General Practitioner and Bariatric Physician

There are several types of weight loss surgery – also known as bariatric surgery – that can help people living with obesity lose weight when other options, such as lifestyle changes (diet and exercise) have been unsuccessful. This kind intervention includes gastric bypass, gastric sleeve and gastric banding to alter the way the digestive system works, limiting the amount of food that can be consumed or absorbed. Accordingly, bariatric surgery can lead to significant weight loss and improvement in associated health conditions.

How does weight loss surgery work?

Bariatric surgery can help achieve and maintain significant weight loss by:

  • reducing the amount you can eat;
  • reducing the absorption of calories; and
  • altering the production and release of a hormone related to hunger (ghrelin), resulting in reduced hunger and increased feelings of fullness.

How much weight will I lose after weight loss surgery?

“Bariatric metabolic surgery is the most effective anti-obesity therapy,” explains obesity expert and bariatric physician Dr Georgia Rigas. “Successful surgery yields significant and sustainable weight loss, on average 25 to 45 per cent of the patient’s original weight.” Weight loss surgery can also help treat conditions that are related to obesity, including type 2 diabetes and sleep apnoea. Other benefits include improved mood, self-esteem and quality of life.

How quickly will I lose weight?

Although the rate of weight loss will vary depending on the type of surgery you have, most people can expect to lose about 4 kg per month to start with.

Who can have weight loss surgery?

In certain people living with obesity, bariatric or weight loss surgery may be recommended after careful patient evaluation by a multidisciplinary team and thorough consideration of potential risks and benefits.  “In conjunction with a calorie reduced diet and increased exercise regimen Australia’s NHMRC and international guidelines recommend bariatric metabolic surgery be considered for a person who falls within one of three categories,” says Dr Rigas.

  • “A person with a Body Mass Index (BMI) of more than 30 and poorly controlled type 2 diabetes
  • “A person with a BMI of more than 35 and at least one comorbidity or complication
  • “A person with a BMI of more than 40.”

Weight loss surgery is usually considered only after dietary and medical treatments have failed.

People considering weight loss surgery should be:

  • motivated to lose weight;
  • realistic about their expectations; and
  • willing to commit to both lifestyle modifications and long-term follow-up with their doctor and other health professionals.

Can teenagers have weight loss surgery?

Weight loss surgery is sometimes appropriate for adolescents aged older than 15 years. Overweight teenagers should talk with their doctor about whether they are eligible for bariatric surgery, and which type of surgery would be most suitable for them.

Risks of bariatric surgery

However bariatric surgery is not a quick fix. Many people regain some of the initial weight lost, and all patients are at risk of complications related to any kind of major surgery. “Healthcare practitioners can be proactive in managing people living with obesity who have experienced some modest weight regain and help turn this around,” Dr Rigas says. “Lifelong follow up us required to ensure nutritional or other complications don’t occur or are picked up in a timely manner.” 

Addressing the global obesity epidemic requires evidence-based strategies that encompass lifestyle modifications through diet, exercise and behaviour changes possibly in tandem with pharmacotherapy or bariatric surgery when appropriate. As with all chronic disease treatment, successful obesity management relies on personalised approaches tailored to each person’s needs and preferences. For advice on how making the most of evidence-based weight loss treatments and improve your health, talk with your GP. 

Support from family and friends is important if you are considering weight loss surgery.

Is there any preparation needed before weight loss surgery?

Your doctor will let you know what preparations are needed, depending on the type of surgery you are having.

You will probably be referred to a dietitian before your surgery to get advice on healthy eating. You’ll also need to improve your levels of physical activity. Some people are referred to a psychologist or counsellor to address their eating habits before surgery.

A very low-calorie diet is usually prescribed for at least 2 weeks before the surgery to help reduce the chance of complications. This usually means having meal replacement shakes.

Can I eat normally after weight loss surgery?

Immediately after your surgery, you won’t be able to have anything to eat for a few days. After starting on liquids, you’ll move to pureed food, then a soft diet and then solid foods.

Long-term, you won’t be able to eat the same amount after your weight loss surgery. Small portions are essential, and you usually need to eat slowly, chewing your food well. Eating small meals on a regular basis is often recommended. It’s also important to choose nutritious meals to reduce nutrient deficiencies.

Will I need to take vitamins after having weight loss surgery?

After most types of bariatric surgery, your doctor will recommend you take regular vitamin and mineral supplements. This is because the surgery can affect your ability to absorb sufficient nutrients from food. When you don’t absorb adequate amounts of nutrients, you can develop problems such as anaemia or osteoporosis.

Recommended supplements typically include:

  • iron;
  • vitamin B12;
  • folic acid;
  • calcium;
  • vitamin D;
  • zinc; and
  • thiamine (vitamin B1).

Regular blood tests are usually recommended to test your levels of key nutrients to ensure that you are not deficient. Lifelong vitamin and mineral supplementation is generally needed.

Can weight loss surgery be reversed?

Some weight loss surgery procedures can be reversed, but others can’t. Make sure you understand beforehand whether there is an option for you to have the procedure reversed.

Will I need ongoing treatment and follow-up?

It’s recommended that people who have had weight loss surgery have lifelong follow-up. Follow-up involves:

  • checking on your weight;
  • ensuring you do not have any nutritional deficiencies;
  • checking for side effects; and
  • checking you are taking any prescribed nutritional supplements.

Do I need to change my lifestyle to maintain weight loss?

Weight loss surgery restricts the amount of food you can eat, but it’s also important that you eat foods that are nutritious and not too high in calories. Getting enough physical activity (at least 30 minutes on most days) is also important for continuing weight loss and maintaining weight loss.

Your doctor and other members of your health care team will give you advice on how to reach your weight loss goal and keep the weight off.

Does weight loss surgery always work?

Some people find that they don’t lose as much weight as they expected following weight loss surgery, while others may regain some of the lost weight.

It’s very important that you have ongoing follow-up with your doctor and other health professionals involved in helping you to lose weight.

Long-term lifestyle changes, such as increased physical activity and eating a healthy diet, are essential in losing weight andnmaintaining weight loss, even after you’ve had weight loss surgery.

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