Today we would like to take about malnutrition after weight loss surgery. Weight loss surgery is an excellent tool to aid individuals in their journey to a healthier life. Altering the digestive system during bariatric surgery can have long-term effects on how the body absorbs the nutrients it requires to remain healthy and functional.
One well-known long-term complication after having weight loss surgery is malnutrition and can be potentially life-threatening. The chances of individuals developing complications related to nutrient absorption vary by procedure and the means used during surgery to alter the digestive system.

What Is Malnutrition?
When the body does not get enough essential vitamins and minerals (micronutrients) or enough calories from fat, carbs, and protein (macronutrients) it can result in malnutrition.
Nutrition is defined as “the intake, absorption, and utilization of food and how it relates to the dietary needs of the body”. When we ad the prefix mal- which means “bad” or “poor” to the word nutrition, it is referring to an unbalance in what the body is getting vs what it needs.
What Type of Malnutrition Can Be Caused by Weight Loss Surgery?
According to the World Health Organization, there are 4 types of malnutrition: deficiencies, being underweight, stunting, and wasting. Each type of malnutrition is a result of a unique cause. The types of malnutrition that patients have experienced after weight loss surgery fall under deficiencies and can be protein-energy malnutrition, micronutrient deficiencies, or a combination of both.
Why Does Malnutrition Happen after Weight Loss Surgery?
For some patients, who are considering or who have had weight loss surgery, hearing that one of the risks of the surgery is losing too much weight may sound more like a benefit than a risk. But this can warrant hospitalization or possibly, death.
Malnutrition can happen after weight loss surgery because:
- The patient fails to follow the recommended post-surgery diet;
- The patient’s body is unable to process the nutrients they do consume;
- A combination of both reasons above.
Which Weight Loss Surgeries Are Higher Risk for Malnutrition?
Weight loss surgeries that limit the amount the patient can eat and also the amount of nutrition that the body can absorb are the ones that pose the highest risk of resulting in malnutrition. Gastric bypass surgery (Roux-En-Y) alters not only the stomach size but also makes changes to the digestive system and brings increased risks for malnutrition issues.
Also, bariatric duodenal switch surgery increases the risk of malabsorption and deficiencies that lead to malnutrition. This is one reason that there has been a decline in the performance of duodenal switch surgeries in the United States in recent years.
What Is The Risk of Malnutrition after Gastric Sleeve Surgery?
As previously stated, the risks of malnutrition after weight loss surgery are higher with gastric bypass surgery and duodenal switch surgery. Only 12% of patients experience malnutrition in some form after having gastric sleeve surgery. As stated above, most instances of malnutrition can be avoided by following the post-operative diet and consistently taking the supplements recommended by your doctors and nutritionist.
Which Weight Loss Surgeriesย Are Low Risk for Malnutrition?
Bariatric procedures that decrease the size of the stomach but do not alter the digestive system or the body’s ability to absorb vital minerals and vitamins, such as gastric sleeve, gastric banding, or the endoscopic sleeve gastroplasty procedure are less likely to result in serious malnutrition complications.
Things to know ESG procedure or Endoscopic Sleeve Gastroplasty (Accordion Procedure)
Endoscopic Sleeve Gastroplasty or ESG procedure or Accordion Procedure. What it is and everything you need to know.This non-surgical sleeve done through endo...
What Are The Signs and Symptoms of Malnutrition?
Symptoms of malnutrition will vary depending on the root cause of the deficiency but typical symptoms include:
- Fatigue & apathy
- Weakness
- Dry skin
- Brittle or dry hair
- Weight loss & loss of subcutaneous fat
- Loss of muscle mass
- Fluid accumulation that may hide weight loss
- Poor wound healing
- Bleeding gums
- Dry eyes
How Can I Avoid Malnutrition after Weight Loss Surgery?
The first step in mitigating the risks of malnutrition after bariatric surgery is to understand how serious the condition can be, closely follow your post-op dietary plan, take all necessary supplements to ensure you are getting all the nutrients your body needs, and know the signs of malnutrition so you can act quickly if you begin to experience them.
Tips to Prevent Malnutrition after Weight Loss Surgery
- Eat a diet rich in nutrients and whole foods as instructed by your doctor and nutritionist.
- Maintain consistent follow up with your doctor.
- Take daily recommended vitamins & supplements; the following are recommended by the American Society for Metabolic and Bariatric Surgery:
- Vitamin B1 (thiamin);
- Vitamin B12 (cobalamin);
- Folic acid;
- Iron;
- Vitamin D and calcium;
- Zinc;
- Copper.
- Stay hydrated.
- Avoid empty calories from sugar, junk foods, and processed foods.
- Avoid drinking empty calories.
- Avoid excess alcohol.
How Is Malnutrition Treated?
Prevention would be the best strategy but if malnutrition did become an issue it would be aggressively treated to avoid an emergency situation. Supplements that are prescription strength, protein shakes or other supplemental drinks that are high in nutrients may be added to the diet by the doctor, and hospitalization may be necessary in severe cases including IV administered nutrients.
What Are the Signs of Dehydration after Gastric Sleeve Surgery?
After any type of weight loss surgery, the new diet plan does not allow for drinking with meals or for 30 minutes before and after mealtime. You are also working with a smaller stomach capacity so you may be asking “How do you prevent dehydration after gastric sleeve?”.ย By the time you feel thirsty, chances are your body is already partially dehydrated.
Bariatric surgery often changes the way our body tells us we are hungry or thirsty so the risk of becoming dehydrated is elevated. One of the most common reasons that weight loss patients have to be admitted to the hospital after surgery is due to dehydration.
The signs of dehydration after weight loss surgery include:
- Dry mouth and feeling very thirsty;
- Lower urine production and urine darker in color;
- Dry skin that is slow to return to its position if you pinch it;
- Feeling lightheaded – this is caused by a decrease in blood pressure due to dehydration and should be taken seriously. Drink something that is low or no sugar but contains electrolytes and seek medical attention if the lightheadedness is not alleviated soon afterward.
Diligence in remaining hydrated after weight loss surgery is critical to your ongoing health and the success of your weight loss journey.
Keep Track of Your Fluid Intake
The best way to ensure you are getting enough fluid intake on a daily basis is to keep track of it. Many patients use a 64 oz jug and fill it with water so they can see how much they’re drinking throughout the day. The best way to calculate how much fluid you need is to look at your current weight and divide it in half. If you weigh 180 pounds, you need 90 ounces of fluid a day.
If you or a loved one has had bariatric surgery and is showing signs of malnutrition seek medical attention immediately. If you are interested in learning more about weight loss surgery contact IBI Healthcare Institute today for a personal consultation. We are here to answer all your weight loss surgery questions and would welcome the opportunity to tell you about endoscopic sleeve gastroplasty (ESG), a non-surgical weight loss option. Contact us today, we will help you achieve a better tomorrow!