Weight loss surgery can bring many benefits, in addition to the main goal of weight loss, including improvements in health, wellbeing, quality of life and increased life expectancy. It is however major surgery and as such it carries risks that you need to be aware of.
1. The benefits of weight loss surgery
a) Weight loss
The primary benefit of weight loss surgery is to lose weight. On average bariatric surgery can result in a 50 to 70 percent reduction in excess body weight over three years. The amount of weight lost after surgery depends on the type of operation, your lifestyle and eating habits. In general, gastric bypass patients will lose around 70 percent of their excess weight, sleeve gastrectomy patients will lose around 60 percent and gastric banding patients will lose around 50 percent¹.
b) Improved general health
Morbid obesity can affect the quality of your health and it’s been linked to several serious and life-threatening diseases. These co-morbid conditions include:
• type 2 diabetes,
• high blood pressure,
• high cholesterol,
• gastroesophageal disease (GERD),
• obstructive sleep apnoea,
• severe arthritis,
Steady weight loss following bariatric surgery often improves these health problems.
Metabolic surgery uses bariatric surgery to treat a combination of diabetes, high blood pressure and obesity, known as metabolic syndrome. It can dramatically improve or cure diabetes in some obese patients including some who do not strictly meet the criteria of morbid obesity.
c) Enhanced mood and quality of life
Most people after weight loss surgery gradually have more energy and a more active lifestyle. Having the energy and being able to do more can have a knock on effect in many areas of your life both psychologically and physically.
Often after bariatric surgery, a patient’s social and emotional wellbeing will improve and often result in feeling less depressed. Finding it easier to move around, exercise and join in different activities alongside the positive impact of actually losing pounds, that you have not been able to lose before, can make you feel better about yourself, more fulfilled and confident. This can ripple throughout your life and you may feel capable of being more productive on a daily basis or achieving in areas such as your career.
d) Greater life expectancy
There have been several clinical studies of bariatric surgery that show surgery improved life expectancy in patients.
2. Risks of weight loss surgery
Like any surgical procedure there are possible risks and complications which will be discussed with you at your initial consultation. They are rare and everything possible will be done to prevent them from occurring.
a) Risks associated during or immediately after weight loss surgery include: internal bleeding, blood clots in the legs (deep vein thrombosis) or lungs (pulmonary embolism, stomach perforation, injury to the spleen, adverse reaction to anaesthesia, leaks in your gastrointestinal system, a stroke, incisions may become infected, hernias may result at the incision site. Other complications:
• Abdominal surgery may cause complications related to your heart such as a heart attack,
• There is a chance that sutures will be rejected,
• Scarring of the tissue can restrict the motion in the small intestine, causing food to eventually block the intestines,
• No surgery is entirely safe and all surgical procedures carry a risk of death (rare).
Who is more at risk of complications during or immediately after weight loss surgery?
A number of risk factors have been identified that increase the risk of complications during or shortly after weight loss surgery. These include:
• Having a BMI of 50 or above.
• High blood pressure.
• Being over 45 years old.
• Being male (obese men tend to weigh more than obese women)
• Having a known risk factor for a pulmonary embolism such as a previous history of blood clots, pulmonary hypertension (blood pressure inside the lungs is particularly high) or obesity hypoventilation syndrome (persistent breathing difficulties related to obesity).
b) Longer term risks
Longer term risks and complications of weight loss surgery vary depending on the type of surgery. They can include:
• Stomal stenosis – This is a common complication in gastric bypass patients that occurs when the hole (stoma) that connects the stomach pouch to the small intestine becomes blocked by a piece of food. The most common symptom of stomal stenosis is persistent vomiting. The best way to prevent stomal stenosis is to always cut food into small chunks, chew the chunks thoroughly and avoid drinking during meals.
Stomal Stenosis occurs in one-fifth of gastric bypass patients.
• Dumping syndrome – Gastric bypass patients may experience ‘dumping’ of their food into the intestines too quickly before it’s been properly digested. Dumping can cause nausea or vomiting, bloating, pain and diarrhoea. It is occasionally associated with brief periods of light-headedness, sweating or heart palpitations due to low blood sugar.
The upside of the effects of dumping means that patients tend to avoid foods (often weight gaining) that lead to dumping.
• Staple disruption – Staple disruption can occur at any time after weight loss surgery but it is uncommon. If the staples pull out the feeling of fullness will probably disappear. A second operation may be required to re-staple the stomach.
• Gallstones – They are small stones, usually made of cholesterol, that form in the gallbladder. If gallstones become trapped in an opening or channel they can irritate and inflame the gallbladder. Symptoms include a sudden intense pain in the abdomen (stomach), nausea and vomiting, jaundice, hernias and low blood sugar.
Around 1 in 12 people will develop gallstones after weight loss surgery usually 10 months after the surgery.
• Gastric band slippage – As the name suggests, the gastric band slips out of position. This can happen months or even years after the operation. When the gastric band slips the upper stomach pouch may become enlarged. Symptoms include heartburn, nausea and vomiting. The band can be re-fixed in the correct position.
Gastric band slippage is a complication that affects around 1 in 50 gastric band patients.
• Malnutrition – Gastric bypass patients are most at risk of vitamin and iron deficiency. Iron and some vitamins are primarily absorbed in the stomach and upper part of the small intestine which is bypassed. Low calcium and protein levels may also occur after gastric bypass surgery. Vitamin and mineral deficiencies are easily prevented by oral supplements or injections.
This may occur in a mild form in as many as 40 percent of patients after gastric bypass.
• Ulcers – Rarely ulcers will form in the stomach or small intestine for gastric bypass patients. Symptoms include abdominal pain, nausea and vomiting. Ulcers are more common in smokers and patients taking medications for arthritis.
• Hair loss – It may be a temporary problem for some patients within the first 6 to 12 months after weight loss surgery and is largely due to vitamin deficiency. Keeping to a post-surgery diet and taking multi-vitamin supplements may help.
• Food intolerance – Happens when your body is unable to tolerate certain foods, such as red meat or green salad. Symptoms include nausea and vomiting and gastro-oesophageal reflux disease (GORD). The reason why food intolerance can develop after surgery is unclear. Generally, avoiding foods that trigger a reaction should help improve symptoms.
Around 1 in 35 people with a gastric band develop food intolerance, often many years after their surgery.
• Excess skin – After dramatic weight loss, people are often left with excess folds and rolls of skin, particularly around the breasts, tummy, hips and limbs. This is because the skin cannot revert to its pre-obesity tightness and firmness.
Cosmetic surgery (eg. apronectomy) is an option to remove the excess skin.
Read more in our blog post: Cosmetic surgery after weight loss surgery
• Psychosocial effects – There are several psychosocial effects that may be related to rapid weight loss. These include:
– relationship problems (as the partner feels nervous, anxious or jealous about the weight loss)
– social awkwardness around occasions that revolve around food, such as family meals.
– worsening of mood when weight stabilises, typically two years after surgery and many people realise that problems that existed before surgery, such as money worries or difficulties at work, are still there after surgery.