Problems with Digesting Fat After Weight-Loss Surgery
If you are severely obese and haven’t been able to lose weight, your healthcare provider
may recommend weight-loss surgery. Weight-loss surgery (bariatric surgery) may help
you lose weight. Losing weight can lower your risk for weight-related problems such
as heart disease, diabetes, sleep apnea, high blood pressure, and arthritis.
Some bariatric surgeries are called restrictive surgeries because they limit how much
food you can eat by limiting how much food can enter your stomach. One example is
sleeve gastrectomy. Another type of bariatric surgery is called controlled malabsorption.
This surgery makes it impossible for your body to break down and absorb food in a
normal way. If your healthcare provider recommends this type of surgery, you may have
a surgery called biliopancreatic diversion with a duodenal switch (BPD-DS). Other
bariatric surgeries combine both a restrictive with a malabsorptive part. This might
be gastric bypass surgery.
What BPD-DS does
BPD-DS is a complicated type of bariatric surgery. It changes the anatomy of your
digestive system in several ways:
It removes most of your stomach.
It bypasses most of your small intestine. Food you eat won’t flow through the bypassed
part of the intestine.
It sends digestive enzymes from your pancreas to an area much farther down in your
These changes mean that your body does not have the time or the space to break down
the fats, proteins, and carbohydrates from foods you eat into smaller particles that
your body can absorb. This causes you to lose weight quickly. You are also likely
to keep the weight off longer than with restrictive type weight-loss surgeries. But
you may also have more long-term complications.
Problems with absorbing fat
After BPD-DS, you will be at high risk for many nutritional problems (deficiencies).
The surgery makes it harder for you to digest and absorb fat. This can mean your body
doesn’t get enough of vitamins. A, D, E, and K. These vitamins are fat-soluble. This
means they dissolve in fat when they are inside your body. If you can't absorb fat,
you won’t be able to fully absorb or store these vitamins.
You need vitamin D to help absorb calcium, so you can have too little calcium in your
body after BPD-DS. This is a very real concern, especially for women. Women are more
likely to have weak bones (osteoporosis). Studies show that 4 years after BPD-DS,
about 2 out of 3 people will be low in vitamins A, D, and K. Half will be low in calcium.
Problems with absorbing fats may cause:
Steatorrhea. Undigested fats cause loose and frequent bowel movements. These are often hard to
control. You may have cramping, foul-smelling diarrhea, and lots of gas.
Vitamin deficiencies and related diseases. Symptoms of these vitamin deficiencies include rashes, bruising or bleeding, night
blindness, and weak bones that are more likely to break.
Calcium deficiency. BPD-DS makes it harder for your body to absorb calcium and vitamin D. Both of these
nutrients are important for healthy bones. Low levels of calcium in your body can
cause broken bones.
Vitamin E deficiency. This problem is rare but it can happen with fat malabsorption. Symptoms include numbness
or tingling in your arms and legs. This is because your nerves aren’t working as they
should. Other symptoms include muscle weakness and vision problems. You are also less
able to fight off infections.
How to live with fat malabsorption after BPD-DS
After BPD-DS you will need to follow a diet high in protein. You will need to take
high doses of fat-soluble vitamins every day. You may also need other dietary supplements.
Limiting the amount of fat in your diet will help prevent steatorrhea. Some people
may also need to take pancreatic enzyme supplements.
The American Society for Metabolic and Bariatric Surgery recommends that you start
taking vitamin A, D, and K supplements about 2 to 4 weeks after BPD-DS surgery. This
will help prevent nutritional deficiencies. You may also need calcium, iron, B-complex,
and multivitamins. Talk with your healthcare provider to find out what supplements
you should take.
You'll need to take these supplements for the rest of your life. You will also need
to be tested regularly by your healthcare provider to check your nutrition and vitamin
levels to prevent complications. Your healthcare provider may need to change these
guidelines to fit your particular condition as guided by your lab results.
Remember that fat malabsorption is the reason you lose weight after the surgery. But
it could cause long-term complications. These risks can be managed, but they will
last for the rest of your life. You will need a regular, lifelong follow-up schedule
with a healthcare provider. Work with your healthcare provider to look at all of the
risks and benefits of BPD-DS as you get ready for bariatric surgery.