Advantages

Best long term weight loss
Able to eat larger meals than gastric bypass
No dumping
Less iron deficiency anemia
Less Vitamin B 12 deficiency

Disadvantages

Potential protein malnutrition (needs continued long term follow up)
Excess gas with eating too many carbohydrates
Diarrhea if eating too many fats
Can develop osteoporosis like the gastric bypass
Potential fat soluble vitamin deficiency (A,D,E,K)

The Duodenal Switch

Weight loss occurs initially as a result of restriction of intake as the stomach is made into a 2-3 cm in diameter tubular structure which holds about 120 cc (as apposed to the GBP which holds about 20 cc). AS the stomach stretches, the weight loss is continued and maintained by malabsorption which occurs as a result of making the alimentary limb 150 cm and the common channel 100 cm with the remainder of the small intestine making up the biliopancreatic limb.

The pyloric muscle is preserved, eliminating dumping and marginal ulcers, and allows the stomach contents to start their digestive process before food enters the intestine. The food and the digestive enzymes mix 100 cm before they reach the large intestine limiting how much can be absorbed maintaining weight loss effectively after the stomach pouch stretches and the patient is able to eat more normally again.