What is Bariatric Nutrition?

Bariatric nutrition is a specialized dietary approach tailored for patients who are or going to undergo bariatric surgery, a surgical procedure conducted on the stomach or intestines to promote weight loss.

The Food Balance Bariatric Nutritional Program

Our nutritional program includes:

  • A comprehensive nutritional assessment
  • Informing the patient of the risk versus the benefit
  • Issues of dehydration
  • Importance of chewing
  • Structured eating and satiety cues
  • Dumping issues
  • Nausea and vomiting
  • The necessity of taking lifelong multivitamins

What is Bariatric Surgery?

Bariatric surgery is an approach for people who are struggling with obesity and want to embark on the path to a weight loss plan. Common bariatric surgery options are gastric bypass, sleeve gastrectomy, and adjustable gastric banding. These operations modify the digestive tract, limiting the quantity of food an individual can consume and, in certain instances, impacting the absorption of nutrients. Whether you have had surgery before or you are thinking about it now, understanding the basics is necessary to achieve the desired results.

Bariatric Surgery and Metabolism Outcomes

Overall, 38% of the world's adult population were categorized as obese in 2023. Bariatric Surgery stands out as the most effective treatment method for morbid obesity in comparison to non-surgical intervention.

The procedure leads to a prolonged significant amount of weight loss and improved obesity-related comorbidities such as type II diabetes, hypertension, hyperlipidemia, sleep apnea, and gastroesophageal reflux.

Who should get Bariatric surgery done?

The NIH in 1991 eligibility Criteria for bariatric surgery includes

  • If you have a BMI of 35 or 40kg\m2 with other conditions such as diabetes, sleep apnea and high blood pressure and have tried to lose weight but have failed to do so.
  • A documented history of weight loss attempts with supervised diet and exercise program
  • No prior history of alcoholism, drug addiction and psychiatric disorders.
  • You are a well-informed, compliant, motivated patient.

Role of RDNs in Bariatric Surgery

Dietitians play a vital role for individuals in both pre and post-bariatric surgery. The clinical practice guidelines for the Perioperative Nutritional, Metabolic, and Surgical Support of Bariatric Surgery Patients state that all patients should undergo an appropriate nutrition evaluation by an RDN before any surgical procedure. Post-surgery, RDNs help the patients to get acquainted with the Bariatric surgery and metabolic changes and help with the bariatric diet plan. Medical Nutrition therapy provided by the dietitian incorporates a 4 step nutrition care process.

  1. Nutritional Assessment
  2. Nutritional Diagnosis
  3. Nutrition Intervention
  4. Monitoring and Evaluation

Critical Role of Pre-op Nutrition in Bariatric Surgery

Once the candidate has been selected adequate nutritional assessment and behavioral dietary guidance are essential in achieving optimal surgical outcomes. Most nutritional evaluations include but are not limited to bariatric knowledge, surgery expectations, eating behaviors and eating patterns. In addition to this weight management history includes onset of obesity, family history and previous dietary and physical activity.

For the best outcome, it is advisable to begin the preoperative dietary regimen for Bariatric Surgery approximately three weeks before to the scheduled procedure. For more specific information on when to initiate your diet, it is advisable to consult with your program's dietitian or coordinator.

Pre-op Diet

Before the Surgery a supervised weight management program, includes a low-calorie diet. The preoperative (pre-op) diet is an essential part of the preparatory process for people undergoing bariatric surgery as it helps to identify nutritional deficiencies. This particular diet is intended to achieve certain aims, such as reducing liver size and promoting weight loss before surgery. Here's an overview of what a normal pre-op diet may include:

1. Low-Calorie Diet (LCD)

  • Generally, patients are recommended to consume between 800 to 1200 calories per day, although individual needs may differ depending on factors such as baseline body weight and metabolic rate.
  • Strive to consume around 70 to 120 grams of protein per day. One can accomplish this by consuming lean protein sources, such as poultry, fish, tofu, and low-fat dairy products.

2. Liquid diet

  • Occasionally, a liquid diet may be advised for a brief duration (e.g., 1-2 weeks) before surgery.
  • Permissible liquids often include transparent broths, popsicles without sugar, and protein shakes.
  • Sufficient consumption of fluids is essential. Strive to consume a minimum of 64 ounces (equivalent to approximately 1.9 liters) of water daily, not including other beverages.

3. Meal Frequency

  • Consume 4-6 smaller meals throughout the day.

Post-operative Diet

Following bariatric surgery, a diet must fulfill two primary goals:

  1. to fulfill nutritional needs while considering calorie limitations, and
  2. to reduce the occurrence of digestive issues such as intolerance, nausea, vomiting, reflux, or dumping syndrome

To accomplish this, it is recommended to adopt a progressive diet approach.

Phase 1: Liquid diet

During the first day after surgery, only clear liquids are permitted. After handling clear liquids, you can add other liquids like:

  • Broth.
  • Unsweetened juice.
  • Coffee or tea without caffeine.
  • Skim/1% milk.
  • Popsicles or sugar-free gelatin.

Phase 2: Pureed diet

After a week of liquid tolerance, you can eat mashed foods. The food should be a smooth paste or thick liquid without solid bits. You can consume 3–6 little meals daily. All meals should have 4–6 tablespoons of food. Eat slowly—30 minutes per meal.

Choose puree-friendly meals like:

  • Lean poultry, fish, or ground meat.
  • Cottage cheese.
  • Scrambled eggs soft.
  • Cereal cooked.
  • Cooked veggies and soft fruits.
  • Straining cream soups.

Stage 3: Soft diet

You can eat soft meals after a few weeks of pureed foods with your doctor's OK. The meal should be tiny, delicate, and easily chewed. You can consume 3–5 little meals daily. One-third to one-half cup of food per meal. Chew each bite until blended before swallowing.

Foods soft include:

  • Lean ground meat or chicken.
  • Flaked fish.
  • Eggs.
  • Cottage cheese.
  • Dried or cooked cereal.
  • Rice.
  • Fruit without seeds or peel, canned or soft.
  • Skinless cooked vegetables.

Phase 4: Solid foods

The gastric bypass diet allows you to gradually eat firmer foods after eight weeks. Eat 3 meals a day, each with 1–1.5 cups of food. Remember to quit eating before you're full. Depending on your solid food tolerance, you can modify meal frequency and size. Discuss your options with your dietitian. Try new foods individually. Foods can induce pain, nausea, and vomiting following gastric bypass surgery.

Foods to avoid after Surgery

  • Breads.
  • Carbonated drinks.
  • Raw veggies.
  • Fibrous cooked vegetables like celery, broccoli, corn and cabbage.
  • Hard or gristly meats.
  • Red meat.
  • Fried foods.
  • Hot or spicy food.
  • Seeds and nuts.
  • Popcorn.

General Characteristics of Diet after Bariatric Surgery

Resumption of oral intake A clear liquid meal regimen can usually be initiated 2 h postoperatively
Energy intake Start on average at 500 kcal with the liquid diet and increase progressively to 1,200 kcal per day in the solid intake phase.
Protein Requirement 1.0-1.5 g/kg of ideal weight or 60–80 g/d
Hydration Intake of more than 1.5 L/d Drink slowly and at least 30 min after meals to ensure a good digestion and prevent early satiety or other gastrointestinal symptoms Clear liquids such as water and tea, avoiding the intake of liquids with sugar, caffeine, carbonation and alcohol are indicated.
Other recommendations The dietary regimen should be structured in small and frequent meals during the day, patients should chew small bites of food thoroughly before swallowing Include at least 5 daily servings of fresh fruits and vegetables to ensure a correct fiber intake

Nutritional Requirement Post Surgery

1. Protein

Following surgery, it is essential to maintain sufficient protein consumption to facilitate the healing process, protect lean muscle mass, and promote overall recovery. The optimal protein consumption generally varies between 60 and 80 grams per day, depending upon variables such as the person's body weight, surgical intervention, and medical state. Protein sources should consist of lean and readily digestible alternatives, such as poultry, fish, low-fat dairy, and plant-based proteins.

2. Multi-Vitamins

After undergoing bariatric surgery, individuals are generally recommended to consume a daily multivitamin supplement to avoid any potential nutrient shortages. These supplements provide a blend of crucial vitamins and minerals that are necessary for optimal health. Consume a daily chewable multivitamin and mineral supplement with a high concentration of nutrients, including at least 18 mg of iron, 400 mcg of folic acid, as well as selenium, copper, and zinc.

3. Calcium Supplements

Calcium supplementation is frequently advised following bariatric surgery to reduce the potential for calcium insufficiency, promote bone health, and assist in several physiological processes. Supplementation becomes necessary due to alterations in the digestive system that can affect the absorption of calcium. It is generally recommended for patients to take a calcium supplement along with vitamin D to achieve the best absorption. The optimal dosage of elemental calcium often falls within the range of 1200 to 1500 milligrams per day, which is best taken in divided doses to enhance absorption.

The Food Balance to the Rescue

The Food Balance is committed to supporting individuals during their post-surgery recovery by providing tailored bariatric nutrition plans." Our proficient nutritionist designs individualized plans customized to enhance your well-being following weight loss surgery. By adhering to our professional advice and maintaining an unwavering commitment to your dietary objectives, you may confidently manage your journey toward bariatric wellness. Book Now and Allow The Food Balance to serve in attaining and sustaining your utmost well-being after undergoing surgery.


Bariatric surgery is a journey towards a healthier, happier life, and diet is a constant companion on that path. A Registered Dietitian Nutritionist (RDN) is necessary at every stage of the surgical process, from preoperative evaluations to postoperative care.


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