Photo Credit: iStock.com/Ege Pamukcu

Researchers laid out nutritional management strategies for clinicians to offer patients before and after bariatric surgery to help sustain weight loss.

Bariatric surgery is an effective treatment to promote weight loss, improve metabolic health, and reduce comorbidities associated with obesity. A patient’s diet before and after surgery influences this surgery’s success rate.

Evelyn Frias-Toral, MD, and colleagues reported effective pre- and postoperative nutrition management strategies in a narrative review for Nutrients.

“The anatomical and physiological changes induced by surgery not only alter food intake but also contribute to specific nutritional deficiencies,” the authors wrote. “Therefore, ongoing supplementation and close monitoring are essential for ensuring optimal recovery and long-term health.”

Preoperative Management Strategies

Screenings

Before starting a preoperative nutrition plan, the researchers recommend that clinicians conduct a comprehensive nutritional evaluation, paying attention to signs of malnutrition and micronutrient deficiencies. These can lead to postoperative complications and/or worse surgical outcomes.

Other medical evaluations required before bariatric surgery include:

• Detailed medical history;
• Thorough physical examination;
• Complete anthropometric assessment;
• Lab tests to evaluate vitamins, electrolytes, iron, folate, calcium levels, and a complete metabolic panel; and
• Psychological evaluation to assess the likelihood of adherence to recommended lifestyle changes after surgery.

Preoperative imaging of the gastrointestinal tract, particularly an abdominal ultrasound to assess biliary tract pathology, can also help inform nutritional management strategies before and after surgery. Screening for obstructive sleep apnea and any other comorbidities should also take place.

Dietary Recommendations

Nutrition management before surgery usually revolves around weight loss, since evidence suggests an improved metabolic profile reduces complications.

Commonly recommended diets include a two-to-three-week liquid-only diet, the ketogenic diet, the Mediterranean diet, and high-protein diets. No matter which is chosen, the diet should be low or very low in calories, as both are associated with a 19% reduction in liver volume and a 17% reduction in visceral adipose tissue. While the best diet varies by individual, some research suggests the liquid diet may lead to fewer postoperative complications.

Alongside sticking to a specific diet, the researchers advised the following:

• Maintain a good intake of vitamin D, B vitamins, and calcium;
• Monitor serum glucose levels if a patient has diabetes; and
• Avoid or limit foods with trans fats and saturated fats.

Postoperative Management Strategies

The authors outlined three goals for a patient and their healthcare team immediately after surgery:

• Ensure hydration and adequate nutrient intake, particularly of protein;
• Minimize muscle mass loss; and
• Promote healing and correct dietary progression.

The researchers also reported diet recommendations for the first month following surgery (Table).

After the first 2 to 4 weeks, clinicians should discuss a long-term nutritional plan with the patient. Popular options include:

• Regulated energy deficit: Personalized diets where someone maintains a controlled caloric deficit while avoiding a nutrient deficit.
• High-quality, balanced diets: This category includes the DASH and Mediterranean diets.
• Micronutrient supplementation: It is important to get key nutrients, such as vitamin B12, D, and iron, though the researchers also warn against excessive supplementation.
• Separation of solids and liquids: A patient may want to separate solid foods from liquids to improve satiety and prevent overeating.
• Protein- and fiber-rich diets: Meals high in protein and/or fiber can help control appetite. Protein also improves satiety and preserves muscle mass, while fiber improves metabolic health and reduces visceral fat.

The researchers also noted that regular follow-ups and continuous medical monitoring reinforce healthy habits and reduce the risk for metabolic complications. Behavioral interventions, like cognitive-behavioral therapy or preoperative education about sustainable eating habits, may also prevent long-term weight gain.

Implementation & Future Research

Implementing thoughtful preoperative and postoperative nutritional management programs can help patients sustain long-term weight loss and minimize complications. That said, other factors not included in this article may influence outcomes, such as obesity medication use and genetics. Delivering effective preoperative and postoperative nutritional care also comes down to coordination between health experts, which presents logistical challenges, and tailoring dietary recommendations to an individual’s health status and genetics.

“Nutritional genomics offers a promising approach for improving outcomes in patients undergoing bariatric surgery,” the authors conclude, adding that the aim should be to develop “highly personalized nutritional strategies and tailored recommendations to optimize care.”