Can I still eat out and prevent nutritional deficiencies after bariatric surgery in Singapore?

After successfully losing weight with bariatric surgery in Singapore, many patients go on to lead healthy, fulfilling lives, including having kids despite the initial rapid weight loss. However, a handful of patients also face nutritional deficiencies, which occurs when the body doesn’t get the necessary amount of nutrients it needs. Deficiencies can lead to a variety of health problems over time, including skin disorders, bone diseases and even dementia. 

This is not what we want. Weight loss should never come at the expense of your health. To be fair, it is not uncommon to have nutritional deficiencies after weight loss surgery as the amount of calories you are able to consume in a day are significantly reduced. Hence, it is important to consume a well-balanced, nutrient-rich diet, which can be quite difficult considering the typical Singaporean diet. 

But there are still ways to prevent malnutrition and weight gain especially if you regularly eat out in Singapore. Here’s my take. 

How does bariatric surgery affect nutrition? 

Because bariatric surgery changes the size of your stomach and the way your small intestine digests and absorbs food, you will inadvertently lose weight — but this also reduces your body’s ability to absorb important macro and micronutrients. As mentioned, bariatric surgery limits the portion size and types of food you can consume, so the quality of your diet has to be well controlled.

Simply put, you need a diet that consists of low calorie dense food to stay healthy while ensuring you get in your nutrients. 

Unfortunately, this is not always the case, especially in Singapore. Many patients develop an intolerance for food such as: 

  • Meat 
  • Dairy products 

Which nutrients are deficient after bariatric surgery? 


According to a report by the American Society of Hematology, about 33-49% of patients develop an iron deficiency or anaemia within 2 years after bariatric surgery. This could already be an underreported statistic, considering that patients with mild anaemia are usually asymptomatic. Alongside, about 19-35% of patients also experience a vitamin B12 deficiency, contributing to the lack of iron. Apart from anaemia, a lack of vitamin B12 can lead to neurological and psychiatric symptoms such as memory disturbance and paresthesia. 


Bariatric surgery patients also remain at high risk of protein malnutrition. Apart from changes in diet and appetite as a cause, changes in digestion is another — about 7-21% of patients experience poor protein digestion after surgery, which consequently limits how much protein the body can absorb. 

The recommended protein intake guideline for regular individuals in Singapore is about 1-1.2g of protein per kg of body weight. I advise increasing this amount by 30% post weight loss surgery — that and getting on a strength training routine to preserve muscle mass. If you struggle to get enough protein, consider protein powder as a supplement. I will elaborate more on diet recommendations later in this article. 

Picture of a plate of Singapore chicken rice

Vitamins and minerals 

Fat soluble vitamins (vitamins A, D, E, and K) have been found to be deficient in bariatric surgery patients; about 50-60% of patients present with low levels of vitamin K post surgery. Water soluble vitamins (vitamins B12, B1 and C) deficiencies are commonly observed too; the same goes for minerals iron, zinz, copper, calcium, selenium and copper. 

The statistics are as follows: 

  • Vitamin A deficiency: 61-69% 2 years after surgery 
  • Vitamin B1 deficiency: 49% 
  • Vitamin C deficiency: 10-50% 

These statistics sound scary, but they are a reality of bariatric surgery patients who fail to follow recommended dietary guidelines. These guidelines are designed to ensure you limit the amount of calories you consume while preventing nutrient deficiencies and muscle loss. 

How can I avoid malnutrition after bariatric surgery in Singapore? 

Here are some general guidelines for Singaporeans: 

  • Eat regular, balanced meals in small portions 
  • Follow a diet low in fat, sweets and high in protein 
  • Keep a daily logbook of your calorie intake, food portions and macronutrients 
  • Choose ground meat as they are usually better tolerated 
  • Opt for high protein food such as meat, fish, seafood, soy milk, tofu 
  • Avoid sugar-containing food and beverages 
  • Avoid alcohol as much as possible. After bariatric surgery, alcohol is absorbed into your immune system a lot faster. FYI – alcohol contains empty calories! 
  • Take your supplements as directed by your healthcare team. This is critical in preventing nutritional deficiencies. 

I often recommend patients to meal prep as this is the easiest way to control what goes into your body. However, if you are unable to meal prep for various reasons, it is still possible to consume healthy, nutritious meals while dining out in Singapore. Dishes like fish soup and ban mian are great options you can find in hawker centres and food courts. 

You may want to use the Healthier Choice Symbol as a guide, but take note that food that’s healthy isn’t necessarily nutritious. Let’s take yong tau foo for example. Is it healthy? Sure. But is it nutritious? Not exactly. While low in calories and rich in dietary fibre from vegetables, yong tau foo has barely any protein.  

As a general rule of thumb, always make sure to include some meat or seafood when dining out and you should be fine. For vegetarians, tofu and tempeh make great protein options too. As mentioned, you may use protein shakes to supplement your protein intake, but I highly recommend meeting your protein needs with food. 

Here is a sample menu from the UCSF Bariatric Surgery Center. There are eight small meals in total. You may choose to eat more or less often, but remember to eat at least 6 small meals a day on top of your multivitamins and mineral supplements. 

You may adjust the menu to fit your preferences, such as mashed potatoes for rice. Once you’ve got the hang of what works for you, you may slowly decrease to three meals a day. 

If you have any questions, I am more than happy to help! 


  2. Lupoli, R., Lembo, E., Saldalamacchia, G., Avola, C. K., Angrisani, L., & Capaldo, B. (2017). Bariatric surgery and long-term nutritional issues. World journal of diabetes, 8(11), 464–474.
  3. Steenackers, N., Van der Schueren, B., Mertens, A., Lannoo, M., Grauwet, T., Augustijns, P., & Matthys, C. (2018). Iron deficiency after bariatric surgery: what is the real problem?. The Proceedings of the Nutrition Society, 77(4), 445–455.
  4. Bal, B. S., Finelli, F. C., Shope, T. R., & Koch, T. R. (2012). Nutritional deficiencies after bariatric surgery. Nature reviews. Endocrinology, 8(9), 544–556. 

This article was written and medically reviewed by Dr. Ganesh Ramalingam, M.D.