Nutritional Considerations After Bariatric Surgery

Bariatric Surgery Nutrition Guidelines

The anatomical changes that occur to the gastrointestinal tract after bariatric surgery have a significant impact on the nutritional needs of an individual in the pre-, peri- and post-operative periods.

Pre-Operative Diet

Nonsurgical pre-operative weight loss is a common practice aimed to promote positive peri- and postoperative outcomes, including decreased surgery time, length of stay, and complications.¹ Whether or not these benefits are significant enough to have nonsurgical weight loss a requirement for bariatric surgery, as many insurance plans currently do, remains controversial. While some argue that medically-supervised weight loss programs create and maintain good habits needed after surgery, others note it is an unnecessary barrier for individuals who have already had multiple unsuccessful weight loss attempts.

Pre-surgical weight loss has very few risks and many benefits. Medical weight loss programs typically have comprehensive approaches that cover nutrition, fitness and behavior strategies to give patients tools for long-term success. Significant weight loss in these programs use meal replacements to achieve a calorie deficit with high protein to facilitate patient adherence.¹

In contrast to a long-term (3-12 month) weight loss requirement from insurance companies, short-term (1-4 weeks) loss with intention on reducing liver volume is common. An enlarged or fatty liver may increase technical aspects for the surgeon, increase risk of bleeding, and lead to complications that convert laparoscopic procedures to open ones.2-4 The ASMBS guidelines recommend initiating a “liver shrinkage diet” prior to surgery for these individuals.⁵ In order to reduce glycogen stores in the liver, very-low-calorie-diets (VLCD) or low-calorie diets (LCD) utilizing ketogenic methods and/or meal replacement products are common. While these diets vary in composition and duration, the literature has shown that 2–4-week pre-op diets between 800-1500 calories successfully reduces liver volume prior to surgery. Baseline liver volume, lean body mass, and adherence are also variables that can impact desired results.^2,6-7 

Post-Operative Diet Progression

Guidelines For Protein Supplements During Bariatric Diet Progression⁸

Immediately after MBS, individuals progress through multiple diet phases with varying textures to minimize post-operative complications. The length of time spent in each phase varies by patient needs and practitioner preference. 

During this diet progression, protein shakes and meal replacements provide a tool to meet protein, fluid, and other nutrient needs that can be difficult to meet on foods/liquids alone. Whey protein with branched-chained amino acids (BCAA) are typically recommended to attenuate lean muscle loss during the rapid weight loss phase.⁸

Short Term Diet Progression

Long Term Diet After MBS

Eating Practices After MBS^5,8,9

• Drink slowly
• Do not drink fluids with meals
• Do not drink from straws
• Eating slowly after extensive chewing
• Avoid foods with nuts, seeds, fibrous skins or peels
• Discontinue or minimize alcohol

After an individual progresses to regular textures, their long-term diet is dependent on their own experiences. Patients typically maintain between 800-1500 calories daily. Small, frequent meals and snacks should not exceed 1 cup volume.⁹ Balanced, well-rounded eating patterns (MyPlate, DASH) that provide adequate fruits, vegetables, fiber, and phytochemicals is recommended.⁵ Protein is emphasized as the primary macronutrient of focus. The ASMBS recommends a minimum of 60 grams daily, but many require a high goal.^5,8 “Protein First” is a common phrase among the community used to encourage individuals to eat protein before more filling grains, fruits, and vegetables. Meeting the minimum 130 grams of carbohydrates is recommended, with an acceptable distribution of 35-50% carbohydrate from total Calories.^8-9 A focus on complex carbohydrates, with no more than 25 grams of simple sugar per meal is suggested to prevent dumping syndrome. 

How Bariatric and Metabolic Surgery Influences Dietary Needs

Nutrient absorption happens throughout the entire digestive tract. While more than 90% food is digested and absorbed before the proximal to mid-jejunum,¹¹ various nutrients are (or can be) absorbed in the stomach and large intestine. The digestive system is an interconnected network requiring secretions from ancillary organs like the gallbladder, pancreas, and salivary glands for proper absorption. Various malabsorptive procedures (RNY, BPD/DS, SADI-S) bypass different sections of the small intestine, which acts as the major source of nutrient absorption. Even the variability between these procedures can be influenced by differences in surface area, access to digestive enzymes, and hormone regulation.

Changes to the Stomach

The Vertical Sleeve Gastrectomy limits the stomach to a volume of 150-200mL while a pouch created in a Roux-en-Y gastric bypass is about 30mL. While restricting gastric volume was thought to be the main driver of weight loss, hormonal effects have shown their influence as well. VSG removes 80% of the stomach, including the fundus and greater curvature, which is where parietal cells that produce ghrelin and leptin are located. The resection of the antrum may also have a role in increasing gastric emptying, glucose/insulin response, and hormone regulation, but more is needed to understand these effects.^13-14 These differences may contribute to the reasons why weight loss, hunger and satiety cues, and metabolic changes after VSG are more similar to that of a RNY rather than Adjustable Gastric Band.

Bypassing the Site of Absorption

Procedures like the AGB and VSG do not alter the GI tract posterior to the stomach, therefore, pancreatic secretions are able to continue to resume its path along the entirety of the small intestine. However, in malabsorptive procedures like RNY, BPD/DS, and SADI-S, segments of the small intestine are relocated to create two different pathways/channels. The limb in which partially digested food is carried is called the alimentary or Roux limb. While the partially digested food does pass through, the absence of biliary and pancreatic secretions significantly stunts absorption.¹⁵ This “bypassed” segment of the GI tract is no longer utilized for absorption but rather as a path to transport biliopancreatic secretions.

The biliopancreatic limb reconnects to the alimentary limb to create the common channel. This shorter segment of the GI tract is where chyme interacts with the digestive secretions and allows for absorption.

Length of Various Parts of the Gastrointestinal System¹⁶

The Length of the Common Channel

It is thought that the length of the common channel may play a role in managing nutrient absorption.¹⁵ Logically, the shorter the common channel, the more malabsorption, the more weight loss. However, this also means less exposure to pancreatic digestive enzymes and less surface area for micronutrient absorption. In 2022, Wang and colleagues reviewed studies comparing different limb lengths in RNY and found that to avoid risks such of protein malnutrition and revision surgery, total alimentary limb length should be greater than 400 cm and common channel should be greater than 200 cm.¹⁷ However, other procedures like the BPD/DS maintain smaller common channels around 75-150cm long.¹⁷ Clinical research is continuing to investigating how various limb lengths balance expected weight loss, protein malnutrition, and micronutrient deficiencies.

Gastric Emptying, Transit Time and Dumping Syndrome

Common Signs and Symptoms of Dumping Syndrome^16,18

• Abdominal pain and stomach cramping
• Diarrhea
• Nausea
• Dizziness
• Flushing
• Fatigue or weakness
• Tachycardia
• Perspiration

Managing and Preventing Early and Late Dumping Syndrome^16,18

• Less than 20-25 grams of total sugar per serving
• Eat small, frequent meals (every 3-4 hours)
• Eat high-fiber meals accompanied by a protein and/or heart-healthy fat sources
• Chew thoroughly and slowly
• Avoid drinking fluids during or shortly after meals
• Avoid foods with added sugars, sucrose, honey, or high fructose corn syrup
• Avoid food concentrated in simple sugars like juice, soda, and frosting
• Avoid alcohol and caffeine

Gastric changes not only influence exposure of nutrients to the small intestine, but change hormone regulation. Faster gastric emptying is thought to promote GLP-1 release, while intestinal transit time alters insulin and glucagon homeostasis.^13,14 Lastly, the ileal break, which senses food in the jejunum and duodenum, act as a negative feedback loop to delay gastric emptying and decrease hunger.³⁷ While these mechanisms are sure to support weight loss and glucose balance, in extremes it can also increase risk of hypoglycemia and dumping syndrome.^13,14

A meal high in simple carbohydrates, can cause distention that results in unpleasant gastrointestinal and symptoms of early dumping syndrome.^16,18 Drinking with meals can contribute to this as well.¹⁶ Late dumping, or reactive hypoglycemia can occur 1-3 hours later due to the rapid insulin response of that high-sugar meal.^16,18 If left unmanaged, these complications can have significant consequences. Fear of dumping symptoms may cause decreased intake of energy and much needed nutrients.¹⁸ To ensure adequate intake and avoid deficiencies, those experiencing symptoms should be counseled on various dietary guidelines to prevent and manage dumping syndrome. If dietary changes are ineffective, pharmacological and surgical approaches may be needed.

Deficiencies Prevalence Among Individuals with Obesity^19-21

Nutrient Deficiencies

There are various nutrition concerns after surgery, but nutrient deficiencies are the most common. In many cases, these can be properly prevented and managed with adequate diet and supplementation.

Nutrient Deficiencies Prior to Metabolic Surgery

Individuals with obesity are more likely to experience micronutrient inadequacies and deficiencies compared to normal-weight individuals.20 This is likely due to the altered metabolic activity influenced by excess adipose tissue. Vitamin D illustrates this well, because it adipose tissue is the nutrient’s main storage site. So it is not the vitamin’s inability to be absorbed (seen after MBS), but rather dysregulated release and utilization of the nutrient.

Many practitioners recommend a multivitamin-multimineral supplements be taken the weeks leading up to sugery. This builds the habit of taking daily supplements. Monitoring and repletion should be conducted as needed, as it is increasingly more difficult to correct after surgery

Deficiencies Prevalence After Bariatric Surgery

After Metabolic Surgery

After bariatric surgery, anatomical, physiological, and dietary changes increase one’s risk of micronutrient deficiency. In addition to the decreased intake and malabsorptive anatomy, other factors such as decreased gastric secretions, food intolerances, and nausea and vomiting can also contribute.¹¹ Incidence of deficiency is dependent on the nutrient and type of surgery.

Identifying Deficiencies

Anthropometric Analysis

Measuring weight can provide important information, but anthropometric analysis that distinguishes between adipose tissue, skeletal muscle mass, and fluid retention can provide information on protein status. While reductions in skeletal or lean muscle mass can be expected, excess loss can be a result of protein-calorie malnutrition that may require supplementation

Annual Laboratory Assessment Needs After MBS ^16,19

^{More details with Parrot et al., SOARD 2017, 13(5): 727-741}

Laboratory Assessment

Laboratory assays can provide accurate and reliable results for micronutrient levels. Due to the high pre- and post-op risk of micronutrient deficiency, regular monitoring of lab values is recommended. The ASMBS’s 2016 Update for Nutrition identifies laboratory indices of deficiencies after bariatric surgery as well as repletion recommendations.¹⁹ Some providers suggest abstaining from supplements for eight hours prior to the lab draw for best accuracy.¹⁶ It is widely thought that supplemental biotin can influence certain laboratory assessments.

Clinical Assessment

Clinical analysis, including physical exams are an integral part of an assessment for nutrient deficiencies. The Nutrition Focused Physical Exam (NFPE) is a standardized methods to evaluate clinical signs of the skin, nails, hair, eyes, and mucus membranes can provide clues for nutrient deficiencies. Almost all vitamins and mineral deficiencies are associated with clinical signs that can be observed with physical exams. Individuals trained in NFPE also evaluate changes in muscle mass that inform protein-calorie malnutrition, including those with excess adipose tissue.

Dietary Assessment

Evaluating dietary intake is quick and easy way to identify certain nutrient deficiencies. However, it is not entirely reliable due to over- and underreporting. Nevertheless, having general idea of foods absent can provide valuable information about the general nutrient intake of an individual.

Environmental Considerations

Other factors that influence an individual’s ability to eat healthy foods or take their recommended dietary supplements should always be considered when evaluating micronutrient deficiencies.

Preventing Micronutrient Deficiencies with Dietary Supplements

The practice of utilize two over-the-counter adult multivitamins has been used for many years, however, it usually does not meet the ASMBS recommendations. Adding additional vitamin and minerals to fill the gaps increases supplement burden and can jeopardize adherence. Having too many dietary supplements to take is one of the number one reasons individuals did not adhere to their recommended supplement schedule.²⁵ The introduction of bariatric-specific multivitamin supplements provides options for individuals to meet these guidelines with less supplements. Providing various forms such as liquids, shakes, soft chews, hard chews, tablets, and soft chews considers individual variability in preference and tolerance.

References

1. Tewksbury C, Williams NN, Dumon KR, Sarwer DB. Preoperative Medical Weight Management in Bariatric Surgery: a Review and Reconsideration. Obes Surg. 2017;27(1):208-214. doi:10.1007/s11695-016-2422-7

2. van Wissen J, Bakker N, Doodeman HJ, Jansma EP, Bonjer HJ, Houdijk & APJ. Preoperative Methods to Reduce Liver Volume in Bariatric Surgery: a Systematic Review. Obes Surg. 2016;26:251-256. doi:10.1007/s11695-015-1769-53. Edholm D, Kullberg J, Haenni A, et al. Preoperative 4-Week Low-Calorie Diet Reduces Liver Volume and Intrahepatic Fat, and Facilitates Laparoscopic Gastric Bypass in Morbidly Obese. Obes Surg. 2011;21:345-350. doi:10.1007/s11695-010-0337-2

3. Edholm D, Kullberg J, Haenni A, et al. Preoperative 4-Week Low-Calorie Diet Reduces Liver Volume and Intrahepatic Fat, and Facilitates Laparoscopic Gastric Bypass in Morbidly Obese. Obes Surg. 2011;21:345-350. doi:10.1007/s11695-010-0337-2

4. Gils Contreras A, Bonada Sanjaume A, Montero Jaime M, et al. Effects of Two Preoperatory Weight Loss Diets on Hepatic Volume, Metabolic Parameters, and Surgical Complications in Morbid Obese Bariatric Surgery Candidates: a Randomized Clinical Trial. Obes Surg. 2018;28(12):3756-3768. doi:10.1007/s11695-018-3413-7

5. Mechanick JI, Apovian C, Brethauer S, et al. CLINICAL PRACTICE GUIDELINES FOR THE PERIOPERATIVE NUTRITION, METABOLIC, AND NONSURGICAL SUPPORT OF PATIENTS UNDERGOING BARIATRIC PROCEDURES - 2019 UPDATE: COSPONSORED BY AMERICAN ASSOCIATION OF CLINICAL ENDOCRINOLOGISTS/AMERICAN COLLEGE OF ENDOCRINOLOGY, THE OBESITY SOCIETY, AMERICAN SOCIETY FOR METABOLIC & BARIATRIC SURGERY, OBESITY MEDICINE ASSOCIATION, AND AMERICAN SOCIETY OF ANESTHESIOLOGISTS - EXECUTIVE SUMMARY. Endocr Pract. 2019;25(12):1346-1359. doi:10.4158/GL-2019-0406

6. Colles SL, Dixon JB, Marks P, Strauss BJ, O’brien PE. Preoperative weight loss with a very-low-energy diet: quantitation of changes in liver and abdominal fat by serial imaging 1-3. Am J Clin Nutr. 2006;84:304-311. doi:10.1093/ajcn/84.2.304

7. Holderbaum M, Casagrande DS, Sussenbach S, Buss C. Effects of very low calorie diets on liver size and weight loss in the preoperative period of bariatric surgery: a systematic review. Surgery for Obesity and Related Diseases. 2018;14(2):237-244. doi:10.1016/j.soard.2017.09.531

8. Tabesh MR, Maleklou F, Ejtehadi F, Alizadeh Z. Nutrition, Physical Activity, and Prescription of Supplements in Pre- and Post-bariatric Surgery Patients: a Practical Guideline. Obes Surg. 2019;29(10):3385-3400. doi:10.1007/s11695-019-04112-y

9. Lysen LK, Isreal DA. Nutrition in Weight Management. In: Mahan KL, Escott-Stump S, Raymond JL, eds. Krause’s Food and Nutrition Care Process. 13th ed. Elsevier; 2012:462-488

10. Dagan SS, Goldenshluger A, Globus I, et al. Nutritional Recommendations for Adult Bariatric Surgery Patients: Clinical Practice. Advances in Nutrition. 2017;8(2):382. doi:10.3945/AN.116.014258

11. Sawaya RA, Jaffe J, Friedenberg L, Friedenberg FK. Vitamin, Mineral, and Drug Absorption Following Bariatric Surgery. Curr Drug Metab. 2012;13(9):1345. doi:10.2174/138920012803341339

12. American Society of Metabolic and Bariatric Surgery Public Education Committee. Bariatric Surgery Procedures. Published April 2021. Accessed March 27, 2022. https://asmbs.org/patients/bariatric-surgery-procedures#top

13. Quercia I, Dutia R, Kotler DP, Belsley S, Laferrère B. Gastrointestinal changes after bariatric surgery. Diabetes Metab. 2013;40(2):1-16. doi:10.1016/j.diabet.2013.11.003

14. Camastra S, Palumbo M, Santini F. Nutrients handling after bariatric surgery, the role of gastrointestinal adaptation. Eating and Weight Disorders - Studies on Anorexia, Bulimia and Obesity. Published online 2021:1-13. doi:10.1007/s40519-021-01194-5

15. Ciobârcă D, Florinela Cătoi A, Copăescu C, Miere D, Cris G. Bariatric Surgery in Obesity: Effects on Gut Microbiota and Micronutrient Status. Nutrients. 2020;12(235):1-27. doi:10.3390/nu12010235

16. Bays HE, McCarthy W, Burridge K, et al. Adult Obesity Algorithm eBook: Detailed overview of Obesity Medicine. Published online 2021. Accessed March 27, 2022. https://obesitymedicine.org/obesity-algorithm/

17. Wang A, Poliakin L, Sundaresan N, et al. The role of total alimentary limb length in Roux-en-Y gastric bypass: a systematic review. Surgery for Obesity and Related Diseases. 2022;18(4):555-563. doi:10.1016/j.soard.2021.08.022

18. Scarpellini E, Arts J, Karamanolis G, et al. International consensus on the diagnosis and management of dumping syndrome. Nat Rev Endocrinol. 2020;16(8):448-466. doi:10.1038/s41574-020-0357-5

19. Parrott J, Frank L, Rabena R, Craggs-Dino L, Isom KA, Greiman L. American Society for Metabolic and Bariatric Surgery Integrated Health Nutritional Guidelines for the Surgical Weight Loss Patient 2016 Update: Micronutrients. Surgery for Obesity and Related Diseases. 2017;13(5):727-741. doi:10.1016/j.soard.2016.12.018

20. Kaidar-Person O, Person B, Szomstein S, Rosenthal RJ. Nutritional deficiencies in morbidly obese patients: A new form of malnutrition? Part B: Minerals. Obes Surg. 2008;18(8):1028-1034. doi:10.1007/s11695-007-9350-5

21. Kaidar-Person O, Person B, Szomstein S, Rosenthal RJ. Nutritional deficiencies in morbidly obese patients: A new form of malnutrition? Part A: Vitamins. Obes Surg. 2008;18(7):870-876. doi:10.1007/s11695-007-9349-y

22. Vitamin D - Health Professional Fact Sheet. Accessed May 5, 2022. https://ods.od.nih.gov/factsheets/VitaminD-HealthProfessional/

23. Sherf-Dagan S, Buch A, Ben-Porat T, Sakran N, Sinai T. Vitamin E status among bariatric surgery patients: a systematic review. Surgery for Obesity and Related Diseases. 2021;17:816-830

24. Litchford MD. Nutrition Focused Physical Assessment: Making Clinical Connections. CASE Software & Books; 2013

25. Mahawar KK, Clare K, O’Kane M, Graham Y, Callejas-Diaz L, Carr WRJ. Patient Perspectives on Adherence with Micronutrient Supplementation After Bariatric Surgery. Obes Surg. 2019;29(5):1551-1556. doi:10.1007/s11695-019-03711-z

Pre-Op Starter Kit

$142.95

Our pre-op vitamins starter kit for bariatric surgery patients helps reduce the size of the liver and enhances patient safety prior to weight loss surgery. This 2-week high-protein, low-carbohydrate, low-calorie meal plan will provide you with the quick weight loss… read more

Add to Bag