Losing weight without rearranging your gastrointestinal anatomy has advantages beyond the lack of surgical risk.
The surgical community objects in characterizing bariatric surgery as wiring the inner jaw and cutting into healthy organs just to discipline people’s behavior. They’ve even dubbed it “metabolic surgery,” suggesting that the anatomical rearrangements cause changes in digestive hormones that provide unique physiological benefits. As proof, they point to the remarkable remission rates for type 2 diabetes.
After bariatric surgery, about 50% of obese people with diabetes and 75% of “obese” diabetics go in remission, meaning they have normal blood sugar levels on a regular diet without diabetes medication. Normalizing blood sugar can happen within days after surgery. And 15 years after surgery, 30% remained without diabetes, compared to a 7% remission rate in a non-surgical control group. Are we sure it was the surgery, though?
One of the most challenging parts of bariatric surgery is lifting the liver. Since obese people tend to have such large, fatty livers, there is a risk of liver injury and bleeding. An enlarged liver is one of the most common reasons that a less invasive laparoscopic surgery can turn into a fully invasive open surgery, leaving the patient with a large abdominal scar, along with an increased risk of wound infections, complications, and recovery time. But lose even just 5% of your body weight and your fatty liver can shrink by 10%. That’s why those waiting for bariatric surgery are put on a diet. After surgery, patients are usually is placed on an extremely low-calorie liquid diet for weeks. Could their improvement in blood sugar levels simply be due to caloric restriction, rather than some sort of surgical metabolic magic? The researchers decided to test it.
At a bariatric surgery clinic at the University of Texas, patients with type 2 diabetes scheduled for gastric bypass he volunteered to stay in the hospital for 10 days to follow the same ultra-low-calorie diet—less than 500 calories a day—that would be placed before and after the operation, but without undergoing the procedure itself. After a few months, after they had regained the weight, the same patients then had the actual surgery and resumed their diet, matched daily. This allowed the researchers to compare the effects of caloric restriction with and without surgery—same patients, same diet, with or without surgery alone. If there was some kind of metabolic benefit to the anatomical rearrangement, the patients would do better after the surgery, but somehow, they actually did worse.
Caloric restriction alone led to similar improvements in blood sugar levels, pancreatic function, and insulin sensitivity, but many measures of diabetes control improved significantly more without surgery. The surgery appeared to put them at a metabolic disadvantage.
Caloric restriction works by first mobilizing fat from the liver. Type 2 diabetes is considered to be caused with the accumulation of fat in the liver and effusion in the pancreas. Anyone can have a “personal fat limit” to safely store excess fat. When this threshold is exceeded, fat is deposited in the liver, where it can cause insulin resistance. The liver can then unloading some of the fat (in the form of a fat transport molecule called VLDL), which can then accumulate in the pancreas and kill from insulin-producing cells. By the time diabetes is diagnosed, half of our insulin-producing cells may be gone destroyed byas shown below and at 3:36 in my video Bariatric surgery versus diet to reverse diabetes. Put people on a low-calorie diet, however, and this whole process can be done vice versa.
A large enough calorie deficit can cause a profound drop in liver fat sufficient to restore the liver’s sensitivity to insulin within seven days. Keep this up and the calorie deficit can reduce liver fat enough to help normalize levels of pancreatic fat and work in just eight weeks. Once you get below your personal fat limit, then you should be able to summary normal caloric intake and keep your diabetes at bay, as shown below and at 4:05 video.
The bottom line: Type 2 diabetes is reversible with weight loss if you catch it early enough.
Lose more than 30 pounds (13.6 kg) and almost 90% of those with type 2 diabetes for less than four years can achieve non-diabetic blood sugar levels (indicating diabetes remission), while it may be reversible in only 50% of those who have lived with the disease for eight years or more. This is what happens with weight loss through diet alone. For people with diabetes, losing more than double the weight with bariatric surgery, diabetes remission may only be about 75% of those who have had the disease for up to six years and only about 40% for those who have had diabetes longer, as shown below and at 4:41 video.
Losing weight without surgery can provide other benefits as well. People with diabetes who lose weight by diet alone can significantly improve markers of systemic inflammation, such as tumor necrosis factor, while levels worsened significantly when about the same weight was lost by gastric bypass.
What about diabetic complications? A reason to avoid Diabetes is the avoidance of associated conditions such as blindness or kidney failure requiring dialysis. Reversing diabetes with bariatric surgery may improve kidney function, but, surprisingly, may not prevent the onset or progression of diabetic vision loss—perhaps because bariatric surgery affects the quantity but not necessarily the quality of nutrition. This reminds me of a famous study published in The New England Journal of Medicine that randomized thousands of people with diabetes to an intensive lifestyle program focused on weight loss. Ten years later, the study was stopped early because the participants were no longer living or having fewer heart attacks. This may be because they remained on the same heart-clogging diet, but only in smaller portions.
Doctor’s note
This is the third blog in a four-part series on bariatric surgery. If you missed the first two, check it out The mortality rate of bariatric weight loss surgery and The Complications of Bariatric Weight Loss Surgery.
My book How not to diet focuses exclusively on sustainable weight loss. Check it out from your local library or pick it up wherever you get your books. (All proceeds from my books go to charity.)
