How to Beat Weakness After Gastric Sleeve Bariatric Surgery?

Medically Reviewed by Katelyn J. Mock, US-Registered Dietician (R.D.)

Many gastric sleeve patients go into surgery hoping to have more energy. And the good news is that most of them have more strength – but not all the time, and usually not right away.

Weakness After Gastric Sleeve

Improved energy levels are one of the main benefits of weight loss surgery. Weakness or tiredness after gastric bypass surgery is common.[1]Medpage Today
Adverse Events Common After Roux-en-Y Gastric Bypass
“The most commonly reported symptoms following RYGB surgery were fatigue (776 patients, 54.3%)…”
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 However, it is typically the result of an underlying issue.

Here are a few reasons for feeling weak or chronic fatigue after gastric bypass surgery. Find out the solution and try eliminating one of these potential reasons at a time.


Reduced stomach capacity limits the amount of fluid your stomach can hold. Hence, drinking water after bariatric surgery can be challenging for some patients. If you are low on water, your body will have to work harder to function. It takes up more energy and causes you to feel weak.


  • Know dehydration signs like dry mouth, thirst, decreased urine output, fatigue, dry skin, etc. Take steps to ensure you are adequately hydrated.
  • Drink 64 ounces of fluid or more per day after surgery.[2]ASBMS
    Life After Bariatric Surgery
    “Diet – Stay hydrated! Drink 64 ounces of fluid or more each day”
    View in Article

Our US-registered bariatric dietitian Katelyn J Mock explains how sodium regulates the fluid balance in our body.

Vitamin or Mineral Deficiency

Bariatric surgeries affect your body’s ability to absorb vitamins, minerals, and nutrients.[3]NCBI
Bariatric surgery and long-term nutritional issues
“All bariatric procedures, to variable degrees, alter the anatomy and physiology of the gastrointestinal tract; this alteration makes these patients more susceptible to developing nutritional complications, namely, deficiencies of macro-and micro-nutrients…”
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Hence, taking vitamin and mineral supplements after surgery is essential. Low levels of iron, Vitamin D, B12, and others can result in extreme fatigue after WLS.


  • Ensure to take supplements as recommended by your bariatric surgeon.
  • Follow your doctor’s guidelines for your post-op diet.

Protein Deficiency

The amount of protein you consume has a direct effect on your energy levels after bariatric surgery.[4]Bariatric Times
Protein Intake after Bariatric Surgery: A Review
“Adequate protein intake among patients who undergo bariatric surgery is important to ensure sufficient amino acid levels throughout the day, especially in the first postoperative year, when the energy balance will be negative and the risk of muscle mass loss is increased…”
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Protein helps balance stress hormones, insulin, and blood sugar levels for hours — keeping your energy high.


  • Take protein-rich foods such as lean meat, poultry, fish, and low-fat dairy products.
  • If you struggle to eat protein, a protein shake can help you keep up with the necessary protein intake.

Our registered dietitian, Katelyn Mock shares useful tips for your protein intake.

Healing Phase

Immediately after weight loss surgery, your body will be adjusting to healing. Every patient recovers from surgeries in different ways. Thus, it is common to feel sluggish and muscle weakness after gastric sleeve surgery. Your body uses more energy for the recovery process.


Make sure you follow your bariatric surgeon’s advice to recover and heal correctly.


Depression after gastric sleeve bariatric surgery can be expected.[5]Psychology Today
Depression after Gastric Bypass Surgery
” …depressions reported both in the scientific literature and in the hundreds of personal anecdotes on gastric surgery blog sites, suggests otherwise. Some have associated depression with the very low-calorie diet followed for several months following the surgery… “
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Some patients feel overwhelmed by the required lifestyle changes after WLS. But these feelings should subside with time. Honestly, discuss your feelings with your bariatric surgeon.


  • If you were on antidepressants prior to surgery, ensure to continue them under your doctor’s advice.
  • Get regular exercise. Exercise helps to release the tension of stress from our bodies.

Too much Exercise

Another possibility of feeling weakness after gastric sleeve bariatric surgery is exercising too much. When you follow a bariatric diet, you probably don’t eat much for carbohydrates. As a result, you may feel hungry and tired after heavy workouts.


  • One of the best ways to burn fat when exercising is to keep your heart rate lower. Eg-walking, light pool aerobics, or light bike riding.
  • Try to do less intense workouts for extended periods.

Bariatric dietitian Katelyn J Mock explains how to get self-motivation for a workout.

Sleep Routine

Each person has different sleep patterns and needs. After surgery, you have to set a routine for sleeping. It’s because sleep plays a huge role in feeling exhausted after bariatric surgery.


  • Keep your bedtime consistent each night as well as your morning wake-up time.
  • Try to get a full night’s sleep every night.

By now, you may be able to identify one or several reasons for your fatigue. If so, take corrective steps — consult your bariatric team and primary care physician as needed.

There are several other reasons fatigue can plague you after bariatric surgery. For the same reasons, it can before undergoing surgery! Therefore, look back at what other factors may be pulling you down.

Remember – None of these reasons or remedies should supplement your doctor’s advice. You should try to make life changes only after speaking to your primary care physician.


1. “Adverse Events Common After Roux-en-Y Gastric Bypass.” Medpage Today

2.”Life After Bariatric Surgery.” ASMBS (American Society for Metabolic and Bariatric Surgery)

3.Roberta Lupoli, Erminia Lembo et al. Bariatric surgery and long-term nutritional issues. World J Diabetes 2017 Nov 15; 8(11): 464–474.

4.Silvia Leite Faria, Mariane de Almeida Cardeal et al. Protein Intake after Bariatric Surgery: A Review. Bariatric Times. 2020;17(7):12–14.

5.“Depression after Gastric Bypass Surgery”. Psychology Today.

This Post Addresses

1. What are the common reasons for extreme fatigue after weight loss surgery?
2. How to improve energy level after gastric sleeve bariatric surgery?
3. How can malnutrition affect your life after bariatric surgery?
4. What deficiencies result in chronic fatigue after gastric bypass surgery?
5. How sleep routine and exercise methods can pull down energy levels after WLS?