bariatric surgery nutrition

Many people mistaken weight loss surgery (also known as bariatric surgery) to be a ‘magic pill’ for weight loss. That is not true. You will only be successful in losing weight with it if you change the way you live and eat for life afterwards. Of special importance is the diet post surgery.

Many people lose weight but they also experience debilitating symptoms like fatigue, hair loss etc due to nutritional deficiencies. This is where good multivitamin supplements can help.

Today, I am going to give you an overview of everything you need to know about the right nutrition following bariatric surgery and particularly tips to help you choose your multivitamin supplements following the procedure.

What is Bariatric Surgery?

Bariatric surgery is a type of weight loss surgery that reduces the size of the stomach. With a smaller stomach, the patient’s appetite reduces greatly resulting in weight loss.

Such a surgery is generally recommended to morbidly obese individuals. As stated above, weight loss surgery is a tool for weight loss but it is not a cure.

How much weight an individual will lose still depends on his/her commitment to eating healthy and exercising regularly.

Naturally, bariatric surgery is usually recommended after failed weight loss attempts that include dietary and lifestyle changes as well as pharmacological interventions.

Types of Bariatric Surgery Procedures

Currently, there are 4 maintypes of bariatric surgery procedures which include:

Roux-en-Y Gastric Bypass (RYGBP)

This is a standard procedure which is most commonly prescribed in the United States as well as in Australia. It is a benchmark procedure by which all other bariatric surgical procedures are measured.

RYGBP entails restriction and mal-absorption of food through the use of staples that create a small pouch in the stomach. This 15 to 30 cc pouch restricts food intake thereby resulting in weight loss. The small intestine is divided and connected to the small pouch so that the food eaten passes directly into the jejunum.

This limits calorie absorption. Roux-en-Y procedure often results in calcium deficiency and bone loss, vitamin B12 deficiency as well as chronic anaemia.

Adjustable Gastric Banding

In this type, the entire stomach is divided into two pouches with the use of a hollow band. The upper pouch is capable of holding only half a cup of food. This keeps patients full longer and sooner than usual.

Adjustable gastric procedure has several advantages: it is reversible and it also reduces the deficiencies seen in other bariatric surgical procedures.

Nausea and vomiting resulting from this procedure could sometimes lead to deficiencies as well. Lack of weight loss and complications requiring the removal of the band make this procedure increasingly unpopular. You can read more about the complications here.

bariatric surgery types

Sleeve Gastrectomy

In Sleeve Gastrectomy (or gastric sleeve) the surgeon divides the stomach vertically using a linear stapling device. This leaves a thin vertical sleeve of the stomach that is approximately 80% smaller than usual allowing the patient to feel full sooner.

Additionally, the surgeon also removes part of the stomach that results in hormone production for further reduction in appetite and food intake. Considered one of the best procedures for weight loss and health improvement.

Biliopancreatic Bypass with Duodenal Switch

This is a complex type of bariatric procedure in which the stomach is fashioned into a small tube leaving the pyloric valve and a small part of the duodenum intact. This restricts the food the patient can eat and also limits absorption.

There are many risks of this procedure including lifelong protein and vitamin deficiencies, increased risk of gallstone formation, bone disease and anaemia.

Nutrition After Bariatric Surgery

As is clear from above descriptions, the food bypasses the intestine or there is restriction on amount of food being absorbed in weight loss surgery patients. Combined with regular exercise, the procedure can certainly help patients lose up to 50-75% of their weight.

However, it is very important to follow the nutritional guidelines and take daily vitamin and mineral supplements; otherwise it is possible that one might develop severe health issues or even regain the lost weight.

Join our Bariatric Surgery Nutrition Support Community on Facebook and discover great tips and advice about nutrition and supplementation after weight loss surgery. Meet others who went through bariatric surgery and just like you face many  nutritional challenges.

Why Are Vitamins and Minerals Important After Weight Loss Surgery?

Vitamins and minerals are vital for the sustainability of life. They help the body build up its immune system, help cells in growth and development, and helps organs do their jobs. For example, Vitamin K helps in clotting of blood when there are cuts /scrapes in the body, Vitamin A helps in well being of the eyes and Vitamin D helps in synthesis of mineral called calcium which helps us have strong bones.

Vitamins are fundamental for life and living beings. They are essential for growth and development of multicellular organisms. Vitamins regulate appetite and hunger, brain activity, nutrient absorption, metabolic rate, fat and sugar metabolism, hormone function, energy storage, and more.

Bariatric procedures can be classified as either Core Restrictive (such as the band or sleeve which restricts the intake of food) or Core Malabsorptive (such as the gastric bypass which changes digestion and absorption). The surgeries are divided as follows..

Bariatric procedures both alters the way food is processed and often cause the stomach to reject nutrient rich food. Fortunately, there are still ways overcome these deficiencies.

Lifelong vitamins and minerals are VITAL to prevent deficiencies since your food consumption and absoption is dramatically reduced.

Deficiencies after Bariatric Surgery

Since bariatric surgery is a restrictive and/or malabsorptive procedure, you will not get adequate nutrition owing to the small portions. There are many cases of patients who have suffered severe vitamin deficiencies. You can read about the case of a woman having severe eye dryness and extreme hearing loss due to vitamin A deficiency following the weight loss surgery here.

Anaemia or severe Iron deficiency is also another side effect of Bariatric surgery. One patient talks of her struggles following bariatric surgery when her iron levels plunged drastically to 0.08 mcg. Although she was taking 2 iron pills, she was still unable to absorb any iron and had to undergo total blood transfusion. Read about her case here.

Hypocalcemia is severe calcium deficiency. Here is the report of a woman who suffered from severe vitamin D and calcium deficiency 5 years after her Roux-en-Gastric Bypass. She eventually needed hospitalization which involved calcium gluconate infusions.

Vitamin B12 deficiency is another common deficiency in gastric bypass because the part of the stomach that absorbs the B12 is itself bypassed. Therefore, doctors recommend taking Vitamin B12 “lozenges” for life to prevent it.

These must be kept under the tongue and not chewed or swallowed unlike other medicines. This allows the oral mucous membrane to absorb the B12. These days, vitamin manufacturers are also making nasal sprays, sublingual pills and oral sprays for preventing this type of deficiency in bariatric surgery patients.

Supplements Every Weight Loss Surgery Patient Needs To Take After the Procedure

Multivitamin Supplement - You must take a daily vitamin and mineral supplement that has all essential vitamins and minerals.

Stay clear from cheap one-a-day multivitamins as they typically do not contain optimum levels of nutrients, and are not well absorbed. A good quality multivitamin will involve taking several pills a day and will not only contain basic essential ingredients but also other vital nutrients and plant extracts including coennzyme Q10, alpha lipoic acid, phytonutrients like resveratrol, curcumin, lutein, lycopene, rutin and green tea  as they are super beneficial for optimum health.

Make sure that your multivitamin delivers at least 1000 mg of vitamin c, 300 iu of vitamin E, 1000 iu of vitamin D (take extra 2000-3000 iu as required) and 200 mcg of B12 in a daily dose. Always take multivitamin in a tablet form and stay clear from liquids and gummies as they have very low levels of nutrients and usually contain various additives, flavours and sweeteners​.

Calcium - Multivitamins always contain calcium and magnesium but never in sufficient amounts to prevent deficiencies. Choose mixed calcium citrate and carbonate pills fortified with magnesium and vitamin D. You need to take 1200-1500 mg per day and you can do so in divided doses.

Calcium tablets are too large to swallow, so make sure you take a high quality brand so the tablets are guaranteed to dissolve quickly. This is especially necessary in the first few days of the surgery when you are required to drink only liquids. Calcium supplementation is very important to prevent osteoporosis and hypocalcaemia.

Join our Bariatric Surgery Nutrition Support Community on Facebook and discover great tips and advice about nutrition and supplementation after weight loss surgery. Meet others who went through bariatric surgery and just like you face many  nutritional challenges.

Iron as Ferrous Fumarate - You should take at least 50-60 mg of elemental iron. Menstruating females may need even more. Begin slowly as large amounts of iron can be constipating. You can take 1-2 iron tablets every 2-3 days. Make sure you drink tons of water and eat fibrous fruits and vegetable stews.

Please note that iron supplements should only be taken when deficiency is established. There are many people who suffer from high iron levels or hemochromatosis  and they must not take supplemental iron. Also men or post-menopausal women usually don't need iron supplements.

Iron is ​not a mineral that can be safely taken every day for a long period of time. Iron accumulation over time may be detrimental because it is involved in generating oxidative stress, a byproduct of energy production, which contributes to chronic diseases - specifically cardiovascular disease. 

Other diseases associated with chronically elevated iron levels include the following: colorectal cancer, neurodegenerative diseases, such as Parkinson’s disease and Alzheimer’s disease, inflammatory diseases, such as arthritis and diabetes.

While it is necessary to have a sufficient amount of iron in your diet in order to avoid anemia, which is a condition caused by insufficient iron in the bloodstream characterized by fatigue and shortness of breath, an overabundance of iron can cause toxicity. Bottom line is never take iron supplements including multivitamins with iron unless you have diagnosed iron deficiency.

Protein- Protein is very important supplement post weight loss surgery and you need 60-80 grams of it daily. Lack of protein can cause hair fall, brittle nails and severe fatigue. Also, as you start dropping weight, you need more protein to maintain the muscle mass.

Start all your meals with proteins; select whey protein isolate which is readily absorbed. Important sources of proteins for earlier stages are yogurt, milk and protein supplement protein powders. You can also add protein powders to your soup recipes by adding non fat milk powder, soy protein powders etc.

The dry protein powder can be mixed with milk which can then be used on cereals, in soups etc. In later stages, you may eat lean protein foods like chicken and eggs alongside protein supplement.

Fish Oil - Your body needs omega-3 essential fatty acids for eye health, joint health and heart health. The chosen pill must contain both EPA and DHA fatty acids. Choose a good brand of Omega 3 having at least 1000 mg fish oil. Take id daily and ensure that the fish oil brand you selected uses fish oil that was put throug a cold distillation process to ensure that is basically free from pesticide and heavy metal residues.


Your body absorbs nutrients very differently following a bariatric surgery procedure. Therefore, you will need multivitamin and mineral supplementation for life. In case you experience symptoms like extreme hair loss, you may have to consult your doctor for even more vitamins.

Vitamins and minerals will help you maintain overall health and also help with maximum weight loss and long term weight maintenance. It is necessary to choose a top quality brand of nutritional supplements to gain all of their benefits.

Vitamins and minerals will be your friends after your surgery and you need to take them for life. It is very important to get blood reports done every 6 months. Review these test results with your doctor and adjust the dosage of the pills as needed.

Read all post surgery instructions carefully and regularly asses your blood reports to ensure that your levels are okay. If not, consider changing your brand of multivitamins.

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About the Author

Barbara is the founder and owner of She is a former research scientist with a serious passion for health. She enjoys writing about nutrition, wellness and lifestyle and empowering people to take control of their health.

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