Bariatric surgery

Obesity is one of the chronic conditions that weighs most heavily on health worldwide. The World Health Organisation estimates that over a billion people live with obesity, and the number keeps climbing. When diet, exercise and medication are not enough to lose weight and keep it off, bariatric surgery becomes a real, evidence-backed option.

It also comes with plenty of doubts. Who qualifies? Is it safe? How much does daily life change afterwards? This article walks through the main questions, though the right call always depends on your own case, which is what a consultation is for.

What bariatric surgery is

Bariatric surgery covers a group of operations that help people with severe obesity lose a significant amount of weight and keep it off. Before you get here it helps to be clear on the starting point, and on the difference between being overweight and obese. These operations work by reducing how much the stomach can hold, so you eat less and feel full sooner.

The techniques used most often today are:

Sleeve gastrectomy (gastric sleeve): around 75-80% of the stomach is removed to leave a narrow tube. It is the most common operation worldwide, because it works well and is less technically complex.
Roux-en-Y gastric bypass: a small stomach pouch is connected straight to the small intestine, so you take in and absorb less. Results are very good, especially in people who also have type 2 diabetes.
Adjustable gastric band: used far less now, as it works less well over time and has more late complications.
Biliopancreatic diversion: a more complex operation with a strong malabsorptive effect, kept for cases of extreme obesity.

Weight loss is not the only benefit. Surgery often puts obesity-related conditions such as type 2 diabetes, high blood pressure, sleep apnoea and high cholesterol into remission or improves them a great deal, which adds years and quality to a patient’s life.

Who qualifies for bariatric surgery

Choosing who should have surgery is a careful medical process, carried out in a specialist unit. This is not cosmetic surgery; it is a treatment for specific clinical situations. The criteria the main scientific societies agree on, such as those of the Spanish Society of Obesity (SEEDO), include:

A body mass index (BMI) of 40 kg/m² or above, with or without other conditions.
A BMI between 35 and 40 kg/m² with at least one serious obesity-related condition, such as type 2 diabetes, high blood pressure, obstructive sleep apnoea, heart disease or severe osteoarthritis.
In selected cases, and following the latest guidelines, a BMI between 30 and 35 kg/m² when type 2 diabetes is poorly controlled.
A clear history of diet, exercise and medication not working despite a reasonable period under medical supervision.
Age roughly between 18 and 65, though some cases outside that range are considered.
A real commitment to the lifestyle changes and long-term follow-up the surgery needs.

Other options are weighed up before surgery. Lifestyle changes are the foundation, and where they are indicated so are medications for obesity, among them Mounjaro and Ozempic, always with a prescription and follow-up. Surgery comes in when those options have not been enough.

It matters just as much to know who is not a good candidate: people with an untreated eating disorder, severe inflammatory bowel disease, advanced liver disease, a serious psychiatric condition that is not under control, or active alcohol or drug use, among others.

Before surgery: a full assessment

Before the operation, the patient goes through a thorough check by several specialists:

A full medical work-up: blood tests, heart and lung function, abdominal ultrasound and whatever else each case calls for.
A nutritional assessment, to correct any existing deficiencies and start learning the dietary changes that follow surgery.
A psychological evaluation, to look at eating patterns, expectations and how ready the person is to stick with the treatment.
A consultation with the surgeon, who explains the recommended technique, the risks and what results to expect.

None of this is red tape. It is what the long-term success of the operation is built on.

What to expect afterwards

Surgery is not a quick fix. It is the start of a long change that needs you on board. The main things to expect:

The first few weeks. The hospital stay is usually two to four days. You start on liquids and move up slowly to solid food over four to eight weeks, adapted to your new anatomy. Tiredness, some abdominal discomfort and changes in bowel habits are normal early on.

Weight loss. It is fastest in the first 12 to 18 months. Most people lose between 60% and 80% of their excess weight, with the sleeve and the bypass giving the best results.

Conditions improving. One of the clearest wins is other illnesses easing off. Type 2 diabetes goes into remission in more than 60-80% of people after a gastric bypass, sometimes before much weight has come off, which points to a metabolic effect of its own.

Follow-up and supplements. Regular check-ups matter after surgery. The body may absorb less of certain micronutrients, such as vitamin B12, iron, calcium and vitamin D, so supplements are usually needed and periodic blood tests catch any shortfall early.

New habits. The operation is a tool; your habits do the real work. A balanced diet suited to your new situation, regular exercise and ongoing medical and psychological follow-up are what make the results last.

Done for the right reasons and in a specialist setting with proper follow-up, bariatric surgery is one of the treatments with the biggest proven effect on overall health. It changes far more than the number on the scales.

If you are living with obesity and want to look at your options, at the Obesity Unit of Dr Christian Leyva we assess your situation in full, answer your questions and support you from the first visit through to follow-up after surgery. You can see the services on offer or book an appointment in Huelva, in person or online.

Bariatric surgery