Low Carb, Now What?

Hayley Miller, RDN

Is Low Carb best for bariatric dieting? What does an expert say?

So, you’ve had bariatric surgery and you are now in the recovery and maintenance phase. You may be wondering what type of diet you should follow if any at all. A low carb (aka Ketogenic diet) is one of the trendier diets today. But is it the best for you, especially having gone through bariatric surgery? 

Let’s begin with a brief anatomy review. Bariatric surgery is the surgical process of making your stomach smaller, thus limiting the amount of calories/nutrients you can consume at one time. Depending on your surgery it can result in the bypass of a portion of the small intestine known as the duodenum and upper jejunum. For reference, there are three sections of the small intestine, the duodenum, jejunum, and ileum. Each section of the small intestine is responsible for absorbing different vitamins and minerals. When a portion is bypassed, specifically the duodenum, it can result in little pancreatic secretion which is needed for the breakdown of food in addition to the decreased absorption of calcium, iron, vitamin b12, and folate.  

So, what type of diet is best to follow? Since bariatric surgery limits the amount of food one can consume at one time, a lower intake of carbohydrates (low carb) and a higher intake of protein is generally recommended.  

Carbohydrates are the naturally occurring sugar, starches, and fiber found in grains, fruits, vegetables, and dairy. A lower intake of carbohydrates (low carb) is recommended because the fiber in carbohydrates results in an increased feeling of fullness. Normally this is an excellent benefit of carbohydrates but with a limited stomach capacity, this may not always be advised. If you are filling up on carbohydrates, you may not consume enough protein throughout the day which is essential to preserve your muscle mass. 

Now, this doesn’t mean you should omit carbohydrates from your diet. Carbohydrates are rich sources of essential vitamins and minerals. Whole grains are rich in B vitamins, vitamin E, Zinc, Magnesium, and fiber. Fruits and vegetables are rich in essential vitamins, minerals, and antioxidants which can help to protect our cells from damage and optimize our health. Dairy is a good source of Calcium which is essential for our bone health and contains probiotics that can help to support our gut health.  

If your surgery resulted in the bypass of the duodenum, decreasing nutrient absorption and a low-carb diet is recommended. However, carbohydrates are rich in nutrients. How can you ensure you are getting enough nutrients to support your health? 

low carb bariatric dieting and supplements

Well, riddle me this: what comes in different shapes, sizes, and colors and helps you thrive? Supplements! Of course, whole foods are always going to be the preferred source to obtain your daily vitamins and minerals. But, when you have had weight loss surgery your body is going to require additional vitamins and minerals. Remember, bariatric surgery limits the amount of nutrients you can come at one time, so supplementation is imperative to help to prevent and combat any nutritional deficiencies.  

What key nutrients do you need on a low carb diet following your weight loss surgery? 

  • Calcium and Vitamin D. Calcium are absorbed in the first part of the small intestine known as the duodenum which is bypassed following bypass or D.S. surgery. Vitamin D is important because it helps to aid in the absorption of calcium. Dairy is an excellent source of calcium; however, it is also a carbohydrate. Therefore, a lower intake of carbohydrates may result in an increased need for both calcium and vitamin D. 
  • Vitamin B-12 and Folate. Folate is found in green leafy greens and vitamin B-12 is only found only in animal products. You may ask yourself, “If it’s found in animal products, and I’m consuming a higher intake of protein, won’t I be fine?” Not necessarily, vitamin B-12 needs intrinsic factor for absorption. Intrinsic factor is secreted by our stomach cells, but intrinsic factor may be decreased due to the surgical narrowing of the stomach. So why is folate relevant to this? Vitamin B-12 assists in the absorption of folate, a decrease in vitamin-B12 may result in a decrease in folate. 
  • B-Vitamins. Whole grains and cereal products are fortified with B vitamins, a lower intake of these foods may result in a deficiency.  
  • Vitamin A. Vitamin A is found in fruits, leafy greens, fish, and liver. Vitamin A is a fat-soluble vitamin, meaning that it needs fats to be absorbed properly. Fat malabsorption is common following bariatric surgery therefore supplementation is recommended. 
  • Trace elements and minerals. These are going to be prevalent in carbohydrates and fortified grains. Again, individuals who have gone through some bariatric surgeries, like the RNY Gastric Bypass or Doudenal Switch have a decreased ability to absorb nutrients thus requiring an added amount.

WLS Afterlife posts a healthy, bariatric recipe every week! 

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Feeling overwhelmed with all these recommendations? Fear not, Persona has you covered! Persona has a team of doctors, pharmacists, registered dietitians, and nutritionists to help support you on your wellness journey. You can get started with the online assessment to get a personalized supplement recommendation based on your weight loss surgery!


Looking for low carb bariatric recipes? Check these out!

Low Carb Pizza – Bariatric Recipe

Low Carb Avocado Brownies

Low Carb Peanut Butter Waffles


Academy of Nutrition and Dietetics Evidence Analysis Library. Nutrition Care in Bariatric Surgery. 2017. Available at: https://www.andeal.org/topic.cfm?menu=5308 .  

Dagan SS, Goldenshluger A, Globus I, et al. Nutritional Recommendations for Adult Bariatric Surgery Patients: Clinical Practice. Advances in Nutrition: An International Review Journal. 2017;8(2):382-394. doi:10.3945/an.116.014258.

Parrott J, Frank L, Rabeba R, et al. American Society for Metabolic and Bariatric Surgery integrated health nutritional guidelines for the surgical weight loss patient 2016 update: micronutrients. Surg Obes Relat Dis. 2017;13(5):727-741. AbstractSherf Dagan S, Goldenshluger A, Globus I, et al. Nutritional recommendations for adult bariatric surgery patients: clinical practice. Adv Nutr. 2017;8(2):382-394. Abstract

At WLS Afterlife, we try share multiple topics, including bariatric dieting, including options like low-carb (low carb) These diets may be good for different surgeries like gastric bypass, gastric sleeve, etc. Either way, please make sure your doctor is aware of any bariatric dieting, like low carb that you are look into

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