Anthropometric
Current height, weight, body mass index
Total weight loss since surgery
Total percent of excess weight loss since surgery
Supplements
Compliance with vitamin and mineral recommendations
Diet
Usual diet recall
Diet progression and consistency of foods
Protein intake
Fruit and vegetable intake
Fluid intake
Meal schedule
Portion size
Food tolerance
Behavior
Separate eating and drinking
Eating habits (speed, size of bites, chewing)
Physical hunger vs. psychological hunger
Coping mechanisms and stress management
Weight maintenance strategies
Physical activity
Type, amount, and frequency
Goal setting
Patient-directed goals
Nutrition Management Guidelines
Diet Texture Progression
The postoperative diet is a staged progression to ensure adequate nutrient intake and tolerance after RYGB. While no standardized recommendations exist across bariatric surgery programs, the need for standardization has been recognized [12]. Typically, patients are given a sugar-free, clear liquid diet after surgery and advanced to full liquid/pureed food, then mechanical soft foods followed by solid food/regular diet over a period of time, taking into consideration individual tolerance and needs [3, 6, 10–14].
Clear liquids are recommended for 1–2 days after RYGB, as is common with many types of surgery, and should be sugar-free, low calorie, and non-carbonated. The clear liquid diet is not intended to meet nutrition needs as patients are typically still in the hospital and getting intravenous fluids.
After clear liquids, a combination of full liquids and pureed foods are recommended for 3–4 weeks (see Table 2). Liquids should be sugar-free, non-carbonated, and low fat. Foods in this stage of the diet have a thin, smooth consistency to minimize pressure on the staple lines and sutures. Solid foods can be blended with liquids to attain the pureed consistency, or patients may choose to use baby foods. At this stage, and for those that follow, high-quality protein intake is of utmost importance and should comprise the majority of each meal.
Table 2.
Blended/pureed
Foods allowed | Foods to avoid | |
|---|---|---|
Protein | Lean fish, tuna, poultry, beef or pork; tofu; eggs or egg substitute; cooked beans; reduced-fat, smooth peanut butter; liquid protein supplements | Fried or breaded meat; meat with visible fat; processed meat |
Dairy | Fat-free (skim) or 1 % milk; light yogurt; nonfat powdered milk; low-fat cottage cheese; low-fat or nonfat cheese; low-fat soymilk | Flavored milk; 2 % or whole milk; ice cream; regular yogurt with sugar; regular cheese |
Fruit and vegetables | Applesauce; mashed potatoes; other cooked fruit and vegetables without seeds or skins | Raw fruit and vegetables |
Starches | Oatmeal; grits; cream of wheat | Bread and rolls; cold cereals; pasta and rice |
Other | Sugar-free gelatin; sugar-free fat-free pudding; sugar-free popsicles | Chewing gum; sweets and desserts |
The soft diet is introduced approximately 1 month after surgery and prescribed for 1–4 weeks (see Table 3). Patients should be able to tolerate all full liquids and pureed foods without pain or regurgitation before advancing to soft foods. Soft foods must be well cooked, moist, ground, shredded, or otherwise able to be chewed into mush when eaten. Protein foods are the priority at meals and can be supplemented with small amounts of fruit, vegetable, or starch.
Table 3.
Soft foods
Foods allowed | Foods to avoid | |
|---|---|---|
Protein | Lean, soft, and moist meats (fish, tuna, poultry, or pork); soft tofu; eggs or egg substitute; soft, low-fat casseroles with soft vegetables; reduced-fat, smooth peanut butter; liquid protein supplements | Crunchy peanut butter; meat that is dry, tough, or chewy; processed meat |
Dairy | Fat-free (skim) or 1 % milk; light yogurt; nonfat powdered milk; low-fat cottage cheese; low-fat or nonfat cheese; low-fat soymilk | Flavored milk; 2 % or whole milk; ice cream; regular yogurt with sugar; regular cheese |
Fruit and vegetables | Fruit and vegetables without seeds or hulls that have been cooked soft; soft unsweetened canned fruits or vegetables; fresh soft fruit | Raw vegetables; fresh, crunchy fruits; fruit and vegetables with tough skins or seeds |
Starches | Oatmeal, grits, and cream of wheat | Bread and rolls; cold cereals |
Other | Sugar-free gelatin; sugar-free fat-free pudding; sugar-free popsicles; light mayonnaise; light or fat-free salad dressing; cooking spray | Chewing gum; sweets and desserts; butter; oils; regular mayonnaise; regular salad dressing |
The regular bariatric diet incorporates all consistencies of foods and is begun 4–8 weeks after surgery (see Table 4). Tolerance of the regular diet will vary widely among patients. Introduction of solid foods should be monitored carefully by both the patient and the bariatric team and done over a period of weeks and months. It is helpful to try one new solid food at a time when the regular diet is first introduced. Once a wide variety of foods are well tolerated, choosing solid, dense foods will result in greater satiety from small portions, thus maximizing weight loss. Meals continue to be predominantly protein based.
Table 4.
Solids
Foods allowed | Foods difficult to tolerate | Foods to avoid | |
|---|---|---|---|
Protein | Lean, moist meats; beans; nuts; eggs or egg substitutes; tofu; vegetarian meat substitutes | Tough or dry meat | Fried or breaded meat; fast-food meat; meat with skin or visible fat; processed meat |
Dairy | Fat-free (skim) or 1 % milk; light yogurt; low-fat cottage cheese; low-fat or nonfat cheese; low-fat soymilk | Flavored milk; 2 % or whole milk; ice cream; regular yogurt with sugar; regular cheese | |
Fruit | Fresh; canned in juice; frozen; cooked without sugar | Fruits with skin or tough peels; dried fruit | Fruit with added sugar; canned in syrup |
Vegetables | Fresh; no salt added canned; frozen; cooked without added fat | Raw vegetables with tough skins or seeds | Fried or breaded vegetables; vegetables with sauces or added fat |
Starches | Dry or toasted whole grain bread; whole grain crackers; baked tortillas; oatmeal; grits; cream of wheat; cold cereal without added sugar; soft cooked potatoes, whole wheat pasta; brown rice | Soft breads and rolls; breads with nuts, seeds, or dried fruit; cold cereal with dried fruit or nuts; rice; pasta | Doughnuts; pastries; white bread; sugary cold cereal; instant noodle or potato dishes; French fries |
Other | Sugar-free gelatin; sugar-free fat-free pudding; sugar-free popsicles; light mayonnaise; light or fat-free salad dressing; cooking spr | Chewing gum; popcorn; spicy foods | Fried or greasy foods; cream-based soups; fast food; sweets and desserts; butter; oils; regular mayonnaise; regular salad dressing |
Calorie Balance and Macronutrients
In all stages of the post-RYGB diet, the goal is to produce a substantial caloric deficit while maintaining an adequate intake of essential macro- and micronutrients [6]. Because the patient’s intake is significantly restricted and the absorption of the nutrients they ingest is hindered by RYGB, the diet must be well designed to meet nutrient needs and prevent deficiencies. As mentioned above, it is essential that patients are thoroughly educated about the ways in which their diet can both keep them healthy and optimize weight loss before they proceed with surgery.
Protein
Protein intake after surgery should be the primary nutrition goal for a number of reasons. During periods of rapid weight loss, the body will lose not only fat but also lean body mass. In order to preserve as much lean body mass as possible, patients must ingest a much higher percentage of their diet as protein than either fat or carbohydrate. The benefits of preserving muscle mass are increased metabolism and ability to burn calories. Additionally, high-quality protein sources in the diet provide the components for protein synthesis in the body, prevent protein deficiency, slow digestion, and therefore increase satiety [15].
It is generally recommended that patients consume 60–80 g of protein per day as soon as their diet has been advanced from clear liquids [3, 8, 9, 11, 12, 14]. Some programs use 1.0–1.5 g/kg ideal body weight to calculate protein needs which generally results in a similar total protein intake [3, 13]. This is slightly higher than the current Dietary Reference Intake of 46–56 g per day for normal adults. In order to meet this protein goal, a patient would need to eat approximately 8–10 oz of lean meat per day or the equivalent of other high-protein foods. While this may be possible in later stages of the diet, for several weeks or months immediately after surgery, liquid protein supplements will likely be necessary to meet this goal. The 60–80 g daily protein intake is ideally distributed evenly throughout the day at 3–5 h intervals and at least three meals [16].
An important consideration to promote optimal health after RYGB is the type and quality of protein. Not all sources or types of protein will be digested or absorbed equally after surgery, and patients will benefit greatly from choosing the highest quality proteins, especially with regard to protein supplements. Two factors that influence protein quality are their indispensable (essential) amino acids (IAA) content and their branched-chain amino acids (BCAA) content. The nine IAAs are those which the body cannot synthesize and therefore must be supplied from the diet. Three of these IAAs are called BCAAs due to their structure and uniquely contribute to both protein synthesis and metabolic function, as compared to the other IAAs that are involved in only one of those functions [16]. This distinction makes the BCAAs protein powerhouses for bariatric patients.
Given these factors, the highest quality whole food protein sources are low-fat milk products (whey and casein proteins), soy, and eggs (egg-white protein). Meat, fish, poultry, beans, and legumes have slightly lower IAA and BCAA contents but are still high-quality protein sources. Grains and nuts also contribute protein to the diet, but are not the best sources of high-quality proteins [16]. With respect to protein supplements, those made from whey, casein, or soy proteins, either as the whole protein or protein isolates, are the gold standard for bariatric patients. Whey protein supplements especially contain all the IAAs and therefore BCAAs are soluble in the stomach and rapidly digested [3]. These types of protein supplements are widely available and affordable for patients and should be used to help patients meet protein goals immediately after surgery. Collagen-based protein supplements do not contain the necessary IAAs and may not be easily digested and absorbed in RYGB patients and so should not be recommended [3].
Fat
For optimal food tolerance and weight loss, dietary fat should be limited in the post-RYGB diet. The fat in foods contributes more than twice as many calories as the equivalent amount of either protein or carbohydrate, thus hindering weight loss. High-fat foods, especially those that are greasy or fried, are often poorly tolerated after RYGB and can cause a number of unpleasant gastrointestinal symptoms. Patients should be advised to limit added fats such as butter, margarine, regular mayonnaise and salad dressing, gravy, cream sauce, oils, cream cheese, and sour cream and choose low-fat, light, or fat-free versions when possible [14]. A helpful guideline is to read food labels and avoid all foods with >5 g total fat per serving.
Carbohydrates
Like protein, the type and quality of carbohydrate in the bariatric diet is important. While a patient’s meals will be predominantly protein, the goal is not a carbohydrate-free diet as is popular in many weight loss programs. Complex, high-fiber carbohydrate foods such as fruit, vegetables, and whole grains are recommended as a small part of every meal for the RYGB patient. These foods will slow digestion and increase satiety as well as provide essential vitamins and minerals.
By contrast, simple, rapidly digested carbohydrate foods such as sweets, processed or refined grains, added sugars, and sugar-sweetened beverages should be avoided. Not only do these foods contribute significant calories with no real nutrient benefits but the digestion of these after RYGB can result in dumping syndrome. Dumping syndrome occurs when a meal containing large amounts of sugar empties quickly into the small bowel which causes a fluid shift into the bowel. This results in symptoms such as nausea, bloating, abdominal cramps, and explosive diarrhea [6]. In order to avoid dumping syndrome and excess calories, all food should have <10 g of sugar per serving. Patients can obtain this information by reading food labels. Artificial sweeteners such as NutraSweet®, Splenda®, Sweet’N Low®, and stevia-based sweeteners are acceptable substitutes for real sugar. They will not cause dumping syndrome and will help with weight loss and maintenance since they contain very few calories.
Behavior Modification
RYGB surgery necessitates a whole lifestyle transformation. The gastrointestinal system must be retrained with the diet progression as the body adjusts to altered digestion and metabolism. Perhaps more challenging though is the psychological retraining involved in learning new eating habits and patterns, recognizing hunger signals, and establishing a new relationship with food. Bariatric patients will benefit greatly from understanding what specific habits and guidelines to follow as well as the rationale behind those guidelines in language and concepts they can understand. This education will improve compliance with the complex guidelines and provide motivation to make the best possible nutrition choices after surgery [3].
The goal of behavior guidelines is to promote optimal nutrient intake while minimizing adverse side effects from food intolerance and maximizing weight loss. Some details of nutrition guidelines will vary between bariatric programs; however, general recommendations are well established and widely used [6, 7, 9, 11–14]. The key nutrition guidelines are summarized in Table 5.
Table 5.
Nutrition behavior guidelines for RYGB
Meal planning | Eat every 3–5 h |
Eat 4–6 times a day | |
Schedule meal times | |
Plan meal content ahead of time | |
Keep a food journal | |
Diet content | 60–80 g protein per day, distributed evenly throughout the day |
Limit added fats and sugars | |
Choose foods with < 5 g total fat and < 10 g sugars per serving | |
When diet has progressed to solid foods, choose moist, solid foods and limit soft, mushy foods | |
Portion size | 1/4–1/2 cup meals during pureed and soft food stages |
1/2–1 cup meals during solid food stage | |
Measure foods before eating | |
Eating habits | Eat protein foods first |
Include 1/8–1/4 cup fruit and/or vegetables at all meals | |
Meals should last 20–30 min; eat slowly | |
Cut food into small bites | |
Chew food very well | |
Fluids | Drink 48–64 oz sugar-free, non-carbonated fluids per day |
Do not drink from 30 min before until 30–60 min after eating |
Overall, the RYGB diet requires planning and scheduling. Meal times and content should be planned in order to meet nutrient goals, avoid grazing or mindless eating, regulate metabolism, and ensure that the meal plan is realistic and feasible for an individual patient’s lifestyle. It is very difficult, for example, to guarantee an intake of 60 g of protein with a restricted meal size without planning which foods and what amounts will be eaten throughout a given day. The diet progression is intentionally slow, and each meal should be a slow, thoughtful process of taking small bites, chewing well, paying attention to hunger and satiety cues, and limiting portions to 1/4 to one cup depending on diet stage. The slowed pace greatly improves tolerance, especially of solid foods, and prevents overeating. For adequate hydration, 48–64 oz of sugar-free, non-carbonated fluids are required per day. Fluids should not be consumed within 30 min of meals, again to improve food tolerance and also to promote satiety. Drinking with a meal can enable foods to be moved from the stomach into the bowel more quickly. This results in larger meals and decreased satiety which hinders weight loss.
Micronutrient Deficiencies Following Gastric Bypass
Due to the restrictive and malabsorptive nature of the RYGB, vitamin and mineral deficiencies can occur. Some of the more common deficiencies include those of calcium, vitamin D, iron, and vitamin B12. More case reports are being published of some less well-known deficiencies including thiamine and copper deficiencies, so clinicians should be aware of signs and symptoms of nutrient deficiencies and screen when appropriate. It should be noted that rates of deficiency in the literature may be skewed due to an inconsistency in testing methods and normal lab ranges. In addition, since certain vitamin levels are not routinely monitored, rates of deficiency of these nutrients may be underreported. The following section provides guidelines for supplementation, signs and symptoms of nutrient deficiencies, laboratory assessment, and causes and prevalence of deficiency as well as treatment. Table 6 outlines recommended supplementation after RYGB.
Table 6.
Guidelines for supplementation after RYGB
Supplement | Dose |
|---|---|
Multivitamin complete | Twice daily |
Calcium citrate with vitamin D | 1,500 mg daily |
Iron (ferrous gluconate)a | 325 mg daily (36 g elemental iron) |
Vitamin B12 | 500 mcg daily |
Patient Instructions
Avoid men’s formula vitamins and “silver” vitamins.
Calcium should be taken in 500 mg doses.
Avoid taking iron and calcium together because they compete for absorption.
Avoid taking calcium and multivitamin together because the multivitamin contains iron.
Vitamin B12
Vitamin B12 is absorbed mainly in the terminal ileum. It has a key role in nervous system function, DNA synthesis, and red blood cell formation. Signs and symptoms of a vitamin B12 deficiency include paresthesias, ataxia, glossitis, fatigue, and coordination disorders. Serum vitamin B12 is the most commonly used indicator of a deficiency. However, elevated methylmalonic acid and homocysteine levels may be more sensitive indicators of a vitamin B12 deficiency [17].
The cause of vitamin B12 deficiency following RYGB is multifactorial. Initially, the release of vitamin B12 from protein-containing foods is incomplete due to a decrease in hydrochloric acid from decreased stomach size. This decrease in stomach size also decreases the amount of intrinsic factor available to bind with vitamin B12 for absorption in the terminal ileum. Food intolerances or avoidance of vitamin B12-rich foods such as meat and fortified cereals is another cause of possible vitamin B12 deficiency following RYGB. Lastly, small bowel bacterial overgrowth (SBBO) following RYGB may cause a low vitamin B12 level due to the utilization of the vitamin by the bacteria [18].
Vitamin B12 deficiency has been noted as early as 6 months following RYGB [19]. The incidence of deficiency has been reported between 7 and 37 % [19–23]. Treatment of a vitamin B12 deficiency has been suggested at 350–550 mcg per day by mouth (PO) or 1,000 mcg/week for 8 weeks PO and then 1,000 mcg/month intramuscularly (IM) [3, 20, 24].
Iron
Iron absorption is most efficient in the duodenum and proximal jejunum. Iron plays a role in oxygen transportation, DNA synthesis, and immunity. The most common signs of iron deficiency include microcytic anemia, fatigue, headache, exercise intolerance, pica, and also oral manifestations including stomatitis and glossitis. Laboratory assessment of iron deficiency should include percent saturation, ferritin, serum iron, and total iron-binding capacity. It should be noted that ferritin is an acute-phase reactant and may be elevated with infection, inflammation, and chronic disease [3].
In addition to bypassing the main site of absorption, iron deficiency can be caused by a decrease in hydrochloric acid which is needed to convert ferric iron into the ferrous state. Iron-rich foods such as meat may be avoided following RYGB which can exacerbate iron deficiency. It has been noted that menstruating women are at increased risk of iron deficiency and may require additional supplementation [21, 24, 25].
The prevalence of iron deficiency has been documented at 20–52 % [19, 20, 23, 25]. Treatment with 50–65 mg of elemental iron 2–4 times a day has been suggested [3, 25]. The absorption of iron is improved with vitamin C, so a 250 mg vitamin C supplement should be considered [26, 27]. Iron supplementation can cause gastrointestinal symptoms that may deter patients from continuing supplementation. Starting with half of a dose and increasing or taking with food may improve tolerance and compliance.
Calcium and Vitamin D
The ileum and jejunum are the main sites of vitamin D absorption, and calcium is preferentially absorbed in the duodenum and proximal jejunum. The most well-known function of calcium and vitamin D is maintenance of proper bone mineralization. Calcium also has a role in blood coagulation, muscle contraction, nerve functioning, and blood clotting. Unlike other vitamin deficiencies that show clear outward signs and symptoms, deficiencies of calcium and vitamin D are less easy to detect without testing. Muscle spasms, joint pain, malformed teeth, and frequent bone breaks may indicate a deficiency. The most accurate blood test to diagnose a vitamin D deficiency is 25-hydroxy vitamin D. Serum calcium should not be used as a marker of bone health. A decrease in serum calcium would not be expected until severe osteoporosis has set in [3]. An elevated parathyroid hormone (PTH) can be indicative of increased bone turnover and should be used in place of serum calcium. A DEXA scan would be ideal in determining actual bone density. However, this test is more expensive and not as easily accessible for the majority of patients.
In addition to bypassing the main site of absorption, deficiencies of calcium and vitamin D can be caused by decreased availability of vitamin D due to sequestering in fat mass and decreased exposure to sunlight. A negative body image may prevent morbidly obese individuals from exposing skin to sunlight which facilitates the conversion of cholesterol to vitamin D. Inadequate bile salt mixing would also cause decreased absorption of vitamin D, and use of proton pump inhibitors can decrease the absorption of calcium [28]. Lastly, since being overweight is protective of bone status, simply losing weight can increase risk of bone demineralization [29].
It should be noted that vitamin D deficiency is prevalent even before weight loss surgery with reports of 16–57 % deficiency before surgery [23, 30–32]. The rate of vitamin D deficiency following RYGB has been reported at 30–73 % [20, 22, 23, 33, 34]. An increase in PTH has been seen in 30–69 % [33, 35, 36].
Copper
Absorption of copper occurs in the stomach and proximal duodenum. A copper deficiency can be exhibited by neurologic symptoms such as polyneuropathy, myelopathy, and ataxia as well as neutropenia and anemia. Some neurologic damage may be irreversible. One of the main signs of a copper deficiency in several case reports following RYGB is a progressive decrease in ambulation [37–40]. Given the similarity in signs and symptoms of copper and vitamin B12 deficiencies, checking vitamin B12 and copper when these symptoms occur may be warranted. A copper deficiency can be confirmed with a serum copper lab test. Some are suggesting using ceruloplasmin as a marker of copper deficiency [41].
The decrease in stomach size as well as bypassing the duodenum in the RYGB is the main cause of copper deficiency. High doses of zinc supplementation can cause a copper deficiency due to competition for absorption [3, 39]. In addition, not all multivitamin/multimineral supplements contain copper or adequate amounts of copper, which can further increase the potential for a deficiency in the RYGB population.
Related posts:
Laparoscopic Malabsorption Procedures: Management of Nutritional Complications After Biliopancreatic Diversion
Effects of Bariatric Surgery on Diabetes
Developing a Successful Bariatric Surgery Program
Gallbladder and Biliary Disease in Bariatric Surgery Patients
Pathophysiology of Obesity Comorbidity: The Effects of Chronically Increased Intra-abdominal Pressure
Laparoscopic Malabsorptive Procedures: Technique of Duodenal Switch
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