A Loaded Problem: Obesity and Diabetes

Why is Bariatric surgery more in the news these days?

Indians are becoming fatter and today more than 40% of the urban population is either overweight or obese. Along with obesity come free riders, such as hypertension, diabetes, heart problems, etc. This puts them at greater risk for complications that could lead to early death.

What is the ‘danger mark’ in obesity?
As a thumb rule, one can say that every ten kg of extra body weight reduces life expectancy by 3 years! Because of higher risks in Asians, all obese patients with a BMI above 35, and those whose BMI is above 30, who have any two conditions – diabetes, hypertension, abnormal cholesterol, heart problems – are advised bariatric surgery.

What are the benefits of bariatric surgery?
The most visible and dramatic benefit is weight loss. Equally dramatic is the way it reduces or normalises associated diseases such as type 2 diabetes, hypertension, abnormal cholesterol, obstructive sleep apnoea etc. In fact, experience has shown us that even before body weight comes down, sugar levels fall and, with it, the dosage of medication required.

What is the association between obesity and diabetes?
With increasing weight gain, the risk of developing Type II diabetes, seen in adult population, increases many fold compared to individuals of normal weight. For example, the risk increases up to eight times at BMI 25, up to forty times at BMI > 30, and more than forty times at BMI > 35 depending on age, gender, ethnicity, duration and distribution of fat.

How do diabetics benefit from a bariatric operation?
The basic energy sources for the body are glucose and fatty acids. Glucose is preferred by most organs, especially the muscles. Insulin assists in the entry of glucose from the blood into muscles and other tissues. Unfortunately, when fat stores increase in the body, they bring in many hormones and other active substances which reduce the efficacy of insulin. The tissues take up fatty acids instead of glucose and blood sugar levels rise. To compensate, the pancreas actually produces more insulin, but even this becomes useless. This is called insulin resistance, the main cause for Type II diabetes. As insulin is ineffective, frequently medicines do not work very well in these patients.

Bariatric surgery changes the hormones produced by the stomach and intestines, and improves the manner in which the gut talks to the brain. This removes the negative influence of fat on insulin and glucose. Hence, even before weight loss occurs, blood sugars come down. This is why bariatric surgery is able to control and achieve better and longer remission of diabetes than the best medication available.

All diabetic societies now recommend bariatric surgery for select patients for better control of diabetes.

Does the ‘eat less and walk more’ advice given to obese and diabetic patients work at all?
Of course it does. It helps obese people with or without diabetes. But, it is not likely to work in all obese people, nor does it work beyond a level. Why? Simply because obesity is not just due to eating more or being less active as many patients will tell you!

To illustrate this point, let us talk about a device called intragastric balloon, which made a grand entry some time ago for weight reduction.The balloon was placed inside the stomach through an endoscope. Once inflated, the balloon occupied a sizeable volume of the stomach, leaving very little space for food. Since the individual with the balloon inside the stomach could not eat much, it was expected that he or she would lose sizeable weight over time. Unfortunately, there was very little weight loss and the balloon has practically gone out of the market!

So how do our bodies maintain balance?
A normal human body, through various mechanisms, maintains a balance between energy input (food intake) and energy output – i.e. it maintains a balance sheet of calories that go in through food and calories that are used up in physical activity. We also have normal ‘set levels’ for water, fat, proteins and carbohydrates in our bodies that serve as guides.

How does the Energy Balance Sheet work?
Let us say, an average person needs ‘X’ number of calories to maintain his weight at a particular level. His body uses this amount of energy for various essential bodily functions such as heart beat, brain activity, routine functioning of various organs and also for physical activity. When this person increases his food intake or reduces physical activity, or both, he will have extra calories in his daily balance sheet.

His body stores the extra calories/energy as fat, as it is a compact form of energy. It adds onto his existing body fat reserves, resulting in higher than the normal ‘set levels’ of body fat. The fat produces a hormone (leptin) which, when it exceeds normal levels, sends strong signals to the brain that bodyfat levels have exceeded the limit. The brain in turn reduces appetite, reduces absorption of food and increases energy expenditure, thereby bringing about a natural reduction of body weight to the ‘set level’.

In simple words, the ‘set point’ mechanism works like a good thermostat in a fridge.

How is it different in obese people?
Obese people are different in the way they deal with energy balance. Their ‘set points’ are different and the mechanism that responds to changes in ‘set points’ that has become erratic. Simply explained, even though the body’s fat and leptin levels are higher, the signals they send are either weak or the brain does not recognise them. It understands the situation wrongly, as if the fat levels were low. Hence, the brain increases appetite and absorption of nutrients and conserves energy expenditure to preserve it for a perceived hunger state. The body adapts to energy-efficient means very similar to energy efficient cars!

It is similar to a non-functional thermostat in a geyser, which does not switch off the geyser even after the ‘set temperature’ is crossed.

How does bariatric surgery differ from dieting?
When a person who is obese goes on a diet, he eats less and feels hungry after a while. He has to fight hunger constantly, which cannot go on all his life. Bariatric surgery, works by restricting the amount of food that ­­­­­one can take or by reducing absorption of fat or by a combination of both. The surgery also changes the hormones produced by the stomach and intestines.Therefore, after bariatric surgery, the patient does not feel hungry, and hence has no problems in eating small quantities.

If ‘set points’ are erratic in obese people, then what does bariatric surgery do for them?
Apart from reducing food intake, the surgery adjusts the gut hormone levels in a beneficial manner. This makes the brain sensitive to signals and it responds correctly to preserve the set points. Simply put, after bariatric surgery, even though the patient eats less, the brain correctly determines that the body fat stores are still very high. It therefore takes corrective actions, leading to decreased appetite, reduced food assimilation and increased energy usage.

If there are so many obvious benefits, why is bariatric surgery not commonly done yet?
Unfortunately, many physicians in India are not fully aware of the ill effects of obesity, and the benefits that patients can reap from bariatric surgery. In fact, overweight and obesity in doctors is no less! Also there are very few medical centres that have experienced surgeons and the special infrastructure required for a successful outcome. All of these factors have resulted in fewer referrals for bariatric surgery.

Now that we have a Central cabinet with at least 3 ministers who have undergone bariatric surgery, it is hoped that patients who can definitely benefit in more ways than one from the procedure will follow suite.