There are always a lot of questions if you're considering a voluntary surgery: Should I undergo the procedure? How do I prepare for it? How long will it take to recover? With so many concerns on your mind, it can be easy to forget the importance of post-surgery dietary and lifestyle changes. However, when it comes to bariatric surgery, post-surgery nutritional considerations should be top of mind from the beginning.

What is bariatric surgery? It includes various surgical procedures on the digestive system with a long-term goal of substantial weight loss. By altering the stomach or small intestine to manipulate the number of calories consumed or caloric absorption, there are typically rapid weight changes, better blood sugar regulation, and more normal metabolism, as well as improved blood pressure and cholesterol levels. More than 250,000 bariatric surgeries take place every year in the United States and are increasing almost 50 percent year-over-year as these procedures become less invasive, safer, and result in quicker recovery times.1  

Significant weight loss is expected in the first year; experts in the field define a “successful” post-op journey as a 50-percent or more loss of excess weight within 12 months of surgery and maintaining the loss afterward.2 Besides the surgical-related risks of any surgical procedure, individuals who undergo bariatric surgery should be aware of the nutritional implications as well. Now that gastrointestinal physiology has changed, individuals must change their lifestyle and eating habits.

Testing for nutritional deficiencies

Before surgery, most individuals will follow a clear liquid diet, which can last from days to weeks; post-surgery the diet can be gradually less restrictive with food options. However, dietary intake – volume, timing, and types of foods – can be significantly restricted and altered post-op indefinitely.

Research suggests that individuals having bariatric surgery should receive regular, full panel screenings to test for common micronutrient deficiencies, such as iron, thiamine, vitamins B12, A, and D, calcium, and folate. A change in dietary intake can also affect biomarkers, such as total protein, albumin, cholesterol, and hemoglobin A1c, which will help you understand macronutrient status and metabolism. Research suggests these should be measured every three months during the first year, every six months in the second year, and every 6-12 months for the third year and thereafter to identify and correct nutritional deficits early.3 

Thorne’s Essential Health Panel or Advanced Health Panel measures most of these biomarkers, as well as additional ones you will want to track. 

In addition to tracking these biomarkers, you will also likely work with a bariatric dietitian. Because each procedure is different, your likelihood of experiencing the following nutritional situations will vary depending on the type of surgery you undergo. The following are four long-term possibilities associated with bariatric surgery and how you can support your nutrition if you experience one of them.

1. Dumping syndrome

For individuals having sections of their stomach removed or bypassed, such as in a gastrectomy or gastric bypass, upward of 50 percent might experience dumping syndrome. This is when the stomach dumps foods and fluids into the small intestine too quickly, causing a change in gastrointestinal motility and digestive hormones, such as gastrin, secretin, cholecystokinin (CCK), and insulin. Dumping syndrome’s most common symptoms are nausea, diarrhea, cramps, and hypoglycemia (and associated symptoms – sweating, shaking, irritability, rapid heartbeat) occurring 10-30 minutes or 1-3 hours after a meal. 

The best way to avoid gastric dumping is to eat smaller meals spaced throughout the day. This way, there is not a large volume of food in the newly smaller stomach at any given time. Avoid drinking fluids with meals. Instead, drink between meals so the fluids have time to make their way through the GI tract and be absorbed into the bloodstream. Lie down after eating because this position helps slow the food's digestion process. Lastly, focus on high-fiber and high-protein foods, while avoiding refined sugars to help maintain regular blood sugar levels. 

Make food sources more nutrient dense – higher in protein or fiber with little added volume – by adding a scoop of Thorne’s Whey Protein or FiberMend.  

2. Malabsorption

Malabsorption is what happens when there is impaired nutrient absorption along the intestines, although in some bariatric procedures reducing the surface area in the stomach or small intestine to decrease absorption is intentional.

For example, the Roux-en-Y gastric bypass (RYGB), a common bariatric procedure, excludes major parts of the stomach and joins the gastrointestinal tract to the small intestine below the duodenum. It is classified as a restrictive and malabsorptive operation. A systematic review of the literature shows there is little or no malabsorption of carbohydrates or protein, although there can be some fat malabsorption after RYGB.4 

A change in fat absorption can alter the way certain micronutrients are absorbed, specifically vitamins A, D, E, and K, which are fat-soluble. These nutrients require the presence of a fat source during absorption and are stored in adipose (fat) tissue, as well as the liver and muscle. As fat stores are liberated with weight loss, it has been well documented that more than 50 percent of both RYGB and the less common biliopancreatic diversion with duodenal switch (BPD/DS) patients will see low levels of vitamin D, and up to 50 percent will see low calcium levels.5

Research suggests vitamin D and calcium supplementation might be necessary in addition to a daily multi-vitamin/mineral supplement.3 Similarly, digestive enzymes can support the complete breakdown of dietary proteins, fats, and carbohydrates.* 

3. Acid Reflux

While it is estimated that more than 30 million Americans suffer from acid reflux (gastroesophageal reflux disease, or GERD), the RYGB procedure can help alleviate this problem, but a gastric sleeve might worsen it.6 The sleeve can add pressure on the lower esophageal sphincter and worsen reflux symptoms: acid taste in the mouth, problems swallowing including pain, bad breath, discomfort in the chest area, sore throat, wheezing, dry cough, erosion or discolored teeth, or classic heartburn. 

If you experience reflux, then don’t lie down after a meal. Stay upright for at least one hour if possible. Chew slowly and fully and extend mealtime so you are not rushing or overeating. Avoid trigger foods that tend to make the problem worse; in particular, alcohol, spicy foods, fried foods, garlic, onions, black pepper, chocolate, coffee, tomatoes, and acidic citrus fruits. Eat protein sources first. 

The physiological alterations to the stomach with a bariatric procedure change the enzymes being released. Some individuals who experience reflux or indigestion can have low hydrochloric acid and could utilize a betaine hydrochloric acid supplement to help maintain the stomach pH needed to break down and digest foods, absorb micronutrients, and support enzymatic reactions.* Consider a probiotic that will support the gut and immune function post-surgery, and switch to a probiotic that will support digestion, vitamin absorption, and normal inflammation through the weight loss journey.* 

4. Gallstones

It is estimated that 30 percent of U.S. bariatric patients will experience gallstones or biliary sludge within the first two years after surgery, with less risk as weight stabilizes over time. Quick weight loss and reduced fat intake can change bile acid secretion from the gallbladder. Similarly, individuals who start with high cholesterol are at an increased risk. 

The incidence of gallstones varies with each procedure; higher rates of gallstones are seen with sleeve gastrectomy or gastric band procedures, in which case, many undergo a gallbladder removal as well.7

To reduce the risk of gallstones after a bariatric procedure, focus on a slow-release, high-fiber diet of whole grains and vegetables that helps manage cholesterol levels. Unhealthy foods that are high in fat, like pastries or fried foods, should be avoided, while healthy fat sources, such as avocados and fatty fish, should be included. Consider a fish oil supplement as well. 

Without a gallbladder, one can also be at higher risk for dumping syndrome. The ox bile in Thorne’s Advanced Digestive Enzymes can provide support after gallbladder removal.*

References

  1. Long-term study of bariatric surgery for obesity: LABS. National Institute of Diabetes and Digestive and Kidney Diseases. Published October 3, 2022. https://www.niddk.nih.gov/about-niddk/research-areas/obesity/longitudinal-assessment-bariatric-surgery [Accessed March 30, 2023.
  2. Cadena-Obando D, Ramírez-Rentería C, Ferreira-Hermosillo A, et al. Are there really any predictive factors for a successful weight loss after bariatric surgery? BMC Endocr Disord 2020;20(1):20.
  3. Sawaya RA, Jaffe J, Friedenberg L, Friedenberg FK. Vitamin, mineral, and drug absorption following bariatric surgery. Curr Drug Metab 2012;13(9):1345-1355.
  4. Mahawar KK, Sharples AJ. Contribution of malabsorption to weight loss after Roux-en-Y gastric bypass: a systematic review. Obes Surg 2017;27(8):2194-2206.
  5. Newbury L, Dolan K, Hatzifotis M, et al. Calcium and vitamin D depletion and elevated parathyroid hormone following biliopancreatic diversion. Obes Surg 2003;13(6):893-895.
  6. El-Hadi M, Birch DW, Gill RS, Karmali S. The effect of bariatric surgery on gastroesophageal reflux disease. Can J Surg 2014;57(2):139-144.
  7. Shubayr N, Elbashir M, Alashban Y, et al. Incidence of gallbladder stone formation after bariatric surgery using ultrasound imaging in the southern region of Saudi Arabia. Cureus 20