What happens when a severely obese, diabetic patient undergoes weight loss (bariatric) surgery? If type 2 diabetes is truly a chronic, incurable progressive disease, then surgery will not alter the natural history.
According to conventional medical wisdom, long standing type 2 diabetics have very high insulin resistance provoking increased insulin secretion from the pancreas. Over time, the pancreas 'burns out' and insulin production falls. As the insulin falls, it is no longer able to compensate for insulin resistance and blood glucose rises, triggering the diagnosis of type 2 diabetes.
Once the pancreas burns out, nothing will revive it, meaning that type 2 diabetes is destined to progress and nothing can change that. Since this abnormality is irreversible, the diabetes should continue unabated despite bariatric surgery. Right?
Actually, in virtually all cases, the type 2 diabetes completely disappears!
A reversible disease
The 2012 STAMPEDE study was a three-year randomized trial of surgery versus medical therapy. Patients were initially randomized to Roux-en-Y surgery, sleeve gastrectomy, or their usual medications without any surgical treatment. At baseline, the average patient was 48 years old, with a hemoglobin A1C of 9.3% (considered very poor control) and body mass index of 36 (considered obese).
Without surgery, the medical treatment group increased both weight and diabetes medication. Their type 2 diabetes continued worsening, as they required more medication to keep control of their blood sugars.
A full 38% of the Roux-En-Y surgical group maintained a hemoglobin A1C < 6% without any diabetic medications whatsoever. Technically, these patients no longer had diabetes. In other words, type 2 diabetes is reversible - even curable! Even the heaviest, most severe type 2 diabetics had disease that is reversible with treatment, but not with standard medications. The ramifications are enormous. Type 2 diabetes is not chronic. It is not progressive. It is fully reversible, but our current medical paradigm of treatment is not correct. Adolescents undergoing bariatric surgery enjoy the same success. In one study, patients starting with an average body mass index of 53, classified as super obese maintained a ninety-pound weight loss after three years. High blood pressure resolved in 74% of patients and 66% of abnormal lipids resolved. And Type 2 diabetes? Glad you asked. A stunning 95% of type 2 diabetes was reversed, with a median hemoglobin A1C of only 5.3% by trial's end. The point once again is that type 2 diabetes is not chronic, not progressive, and not inevitable. It is fully and quickly reversible.
The downsides of surgery
But surgery carries a heavy price. Complications are common with thirteen percent of the participants requiring surgical re-intervention. The most common problem is esophageal strictures requiring dilatation. The esophagus develops scarring. It gradually narrows resulting in difficulty eating. The treatment is to shove progressively larger sized tubes down the patient's throats to open things up (lovely). This procedure is often repeated over and over.
That surgery can cure type 2 diabetes has been known since 1992. For ten years after weight loss surgery patients, most patients maintained normal blood glucose without the need for any medications. This treatment for diabetes is both rapid and long lasting. Normal blood sugars were achieved within two months and maintained for ten years. So the problem was not the disease. The problem was our treatment and understanding.
The benefits extended far beyond their body weight. Many metabolic abnormalities reverted back to normal as well. Sky-high insulin levels plummeted to normal levels. Blood glucose dropped in half. Fasting insulin, a marker of insulin resistance dropped 73%.
Despite all their successes, I don't generally recommend these surgeries for a variety of reasons. The most important, though is that we can derive all the benefits without surgery and all of its complications. However, bariatric surgery studies have a very important lesson to teach. Type 2 diabetes, even in the most severe, long-standing and seemingly recalcitrant patient is an entirely reversible disease.
Surgically enforced fasting
Why is bariatric surgery so successful at reversing diabetes where all the medications and insulins fail? Why does it work? There are many theories.
The foregut hypothesis suggests that the surgical procedure itself provides much of the benefit. Perhaps removing part of the healthy stomach or rewiring normal, healthy intestines into an abnormal, artificial man-made configuration somehow improves things. The normal stomach secretes many hormones, including incretins, peptide YY and ghrelin. Removing the stomach reduces all of these hormones, and perhaps others not yet identified.
The different bariatric procedures do not differ substantially in their ability to reduce insulin resistance. The only variable that matters is how much weight is lost. It did not matter whether you cut the stomach or not. It did not matter if you rewire the intestines or not.
The foregut hypothesis also fails to explain why type 2 diabetes often recurs years later since the stomach does not regenerate the ability to secrete these hormones. This proves what should have been a rather obvious point that the removing healthy stomach (like with the sleeve gastrectomy) doesn't truly have any benefits.
Another natural assumption is that loss of fat mass, both subcutaneous and visceral, leads to the beneficial effects of surgery. We often imagine that fat cells, as a store of energy, just sit around doing nothing all day long, like a sack of potatoes, but it's not really true. Adipocytes actively secrete many different types of hormones.
For example, fat cells secrete the hormone leptin, an important regulator of body weight. As fat mass rises, leptin secretion increases, signaling brain receptors to lose weight. In obesity, the body becomes resistant to the leptin's weight losing effects. Adipocytes also convert testosterone into estrogen, leading to the familiar phenomenon of 'man boobs' in obesity. So adipocytes are not metabolically inert, but active hormonal players.
If adipocytes help sustain obesity and type 2 diabetes, then their removal should normalize the hormonal environment. But there are two problems with this theory. First, type 2 diabetes disappears within weeks - long, long before any substantial loss of fat mass. Second, surgical removal of fat does not provide any metabolic benefit.
Liposuction removes subcutaneous fat but not the visceral fat found in and around the organs. One study of liposuction removed 10 kg (22 pounds) of subcutaneous fat, yet failed to provide any metabolic benefit. There was no significant improvement in the blood sugar readings or any measurable metabolic markers. The only benefits were cosmetic.
Visceral fat is a far greater health risk. Unfortunately, this tendency to gain weight around the abdomen is very common. People with this 'beer belly' often have skinny arms and legs, but a protuberant abdomen. Bariatric surgery preferentially removes this visceral fat, where liposuction only removes subcutaneous fat. This partially explains why bariatric surgery leads to metabolic improvement even before all of the weight is lost.
There is no real magic here. The mechanism of benefit is the simplest and most obvious. All different types of bariatric surgery work because they have one thing in common - a sudden severe caloric reduction. Simply put - Bariatrics is surgically enforced fasting. All the benefits accrue because of the fasting. A study directly comparing the two shows fasting is actually superior to surgery in both weight loss and blood sugar reduction. Fasting produced almost twice the weight loss of bariatric surgery.
So here's the crucial question. If all the benefits come from fasting, why not do the fasting and skip the surgery entirely? Fasting can produce results without postoperative complications, cost, or the need for expensive hospitals, equipment or specially trained surgeons. In essence, fasting is 'bariatric surgery, without the surgery'. Medical Bariatrics.
But my point is not to criticize or praise surgery. There is one essential lesson to be learned from surgical studies. Type 2 diabetes is not a chronic and progressive disease. This is a colossal deception. Instead type 2 diabetes is an entirely preventable and reversible disease. Even the heaviest patients with the most intractable obesity can reverse decades of type 2 diabetes within weeks. Further, the cure does not require invasive surgery, only a deeper knowledge of its root causes. This changes everything. A new hope arises.
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Jason Fung
