Many people who suffer from obesity find it hard to lose weight and keep the weight off with diet
and exercise
alone. This is likely due to foods available and genes.
The National Institutes of Health (NIH) Expert Panel stated that, without surgery, long-term weight
loss is nearly
impossible for those affected by severe obesity. Studies show little long-term success with diet and
exercise
alone.(3) Weight loss surgeries are effective in maintaining long-term weight loss, in part, because
these
procedures change the body’s natural responses to dieting that make weight loss so difficult. When a
person goes
on a diet, their body produces more hormones that cause an increase in hunger and a decrease in
calories burned.
This decrease in calories the body burns is more than explained by the decrease in body size.
Therefore, there are
significant differences between someone who has lost weight by diet and someone of the same size who
has never
lost weight. For example, the body of the person who reduces their weight from 200 to 170 pounds
burns fewer
calories than the body of someone weighing 170 pounds who has never been on a diet. This means that
in order to
maintain weight loss, the person who has been on a diet will have to eat fewer calories than someone
who naturally
weighs the same. Weight loss procedures, unlike diet, also cause biological changes that help reduce
food intake.
Energy (in the form of food) intake is decreased with surgery by restricting stomach size and
limiting absorption.
In addition, weight loss surgery changes the production of certain gut hormones (or signals) that
communicate with
the brain to reduce hunger, decrease appetite, and enhance the feeling of being full. In these ways,
weight loss
surgery, unlike dieting, produces long-term weight loss.(5)