Modern Management of Obesity

1. Dietary management:

Diets to promote weight loss are generally divided into four categories: Lowfat, Low CHO, Low calori, Very low calori. A meta-analysis of six randomized controlled trials found no difference between three of the main diet types (low calorie, low carbohydrate, and low fat), with a 2–4 kilogram weight loss in all studies.

Crash dieting involves taking very low calorie diets. Such diets provide 200–800 kcal/day, maintaining protein intake but limiting calories from both fat and carbohydrates. They subject the body to starvation and produce an average weekly weight loss of 1.5–2.5 kilograms (3.3–5.5 lb). These diets are not recommended for general use as they are associated with adverse effects like loss of lean muscle mass, increased gout, electrolyte imbalances. People attempting these diets must be monitored closely by a physician to prevent complications.

2. Exercise:

With use, muscles consume energy derived from both fat and glycogen. Due to the large size of leg muscles, walking, running, and cycling are the most effective means of exercise to reduce body fat. Exercise affects macronutrient balance. During moderate exercise, equivalent to a brisk walk, there is a shift to greater use of fat as a fuel. The AHA recommentds a minimum of 30 min of moderate exercise for at least 5 days a week.

A meta analysis of 43 RCTs found that exercising alone led to limited weight loss. In combination with diet, however, it resulted in a 1 kilogram weight loss over dieting alone. A 1.5 kilogram (3.3 lb) loss was observed with a greater degree of exercise.

Even though exercise as carried out in the general population has only modest effects, a found, and very intense exercise can lead to substantial weight loss. During 20 weeks of basic military training with no dietary restriction, obese military recruits lost 12.5 kg (27.6 lb). High levels of physical activity seem to be necessary to maintain weight loss.

Signs that encourage the use of stairs as well as community campaigns have been shown to be effective in increasing exercise in a population.

3. Drugs:

Only one anti-obesity medications ORLISTAT is currently approved by the FDA for long term use. It reduces intestinal fat absorption by inhibiting pancreatic lipase.

Rimonabant, a second drug, works via a specific blockade of the Endocannaboid system. It had been approved in Europe for the treatment of obesity but has not received approval in the United States or Canada due to safety concerns. Some agencies recommended the suspension of the sale of rimonabant as the risk seem to be greater than the benefits.

Sibutramine acts in the brain to inhibit deactivation of neurotransmitters.. causing decrease in appetite. However this drug too was banned fearing cardiovascular complications. Practically we have noticed that Sibutramine causes wt gain more than wt loss for some reason!! In 2010, it was found that the incidence of heart attacks and strokes increased in pts taking Sibutramine and since then, the drug fell into disrepute.

There are a number of less commonly used medications. Some are only approved for short term use, others are used off label, and still others are used illegally.

Most are appetite suppressants that act on neurotransmitters. Earlier we used to have amphetamine like drugs like Fenfluramine, now banned due to increased incidence of Pulmonary hypertension.

Recombinant Human Leptin is very effective in those with obesity due to congenital complete leptin deficiency via decreasing energy intake and possibly increases energy expenditure. This condition is, however, rare and this treatment is not effective for inducing weight loss in the majority of people with obesity. It is being investigated to determine whether or not it helps with weight loss maintenance.

The usefulness of certain drugs depends upon the comorbidities present. Metformin is widely used in Obese diabetics and in PCOS. We may have a whole array of drugs based on Ghrelin, Neuropeptide Y and adiponectins in future.

Surgery:

Wt loss surgery is called Bariatric surgery in treatment of Obesity. As every operation may have complications, surgery is only recommended for severely obese people (BMI > 40) who have failed to lose weight following dietary modification and pharmacological treatment.

Weight loss surgery relies on various principles: the two most common approaches are reducing the volume of the stomach (e.g. by gastric banding or gastroplasty). Gastric bypass surgery reduces the length of bowel that comes into contact with food , which directly reduces absorption. Band surgery is reversible, while bowel shortening operations are not.

Some procedures can be performed laparoscopically.

Surgery for severe obesity is associated with long-term weight loss and decreased overall mortality. One study found a weight loss of between 14% and 25% (depending on the type of procedure performed) at 10 years, and a 29% reduction in all cause mortality when compared to standard weight loss measures.

A marked decrease in the risk of Diabetes, Coronary artery disease and Cancer has also been found after bariatric surgery. Marked weight loss occurs during the first few months after surgery, and the loss is sustained in the long term.

The effects of Liposuction on obesity are less well determined. Some small studies show benefits while others show none.

Recently a treatment involving the placement of an intragastric balloon via gastroscopy has shown promise. One type of balloon led to a weight loss of 5.7 BMI units over 6 months or 14.7 kg (32.4 lb). However regaining lost weight is common hence the procedure is still done experimentally.

New drugs in pipeline:

Lorcaserin has been found to be effective in the treatment of obesity with a weight loss of 5.8 kg at one year as opposed to 2.2 kg with placebo. It however, failed to get FDA approval in 2010 due to concerns regarding cancer.

Temporary, controllable gastric pseudo bezoars (swallowable, swellable foreign bodies in the stomach meant to reduce gastric volume from inside the organ) are being tested.