Managing nutrient deficiencies with a bariatric diet

Malnutrition causes a range of health problems and presents a long term issue for gastric bypass patients. Staying healthy doesn’t need to be a daily struggle if you adopt a highly nutritious bariatric diet. Discover the foods that will support your nutrition and weight loss.

After surgery you will need to take multivitamins regularly over your lifetime. This really hit me around 3 months into post op when I noticed my hair was thinning. While it is still too soon for me to develop any serious effects of malnutrition, I know people who have experienced complications years after their surgery. Long term malnutrition can be avoided by a adopting a healthy bariatric diet and taking supplements from the start.

With a surgically restricted stomach pouch and GI tract patients can easily become deficient in macro- and micronutrients. Nutrient deficiencies can lead to anemia, osteoporosis and the more serious effects of protein malnutrition.

What are micronutrients and macronutrients?

Micronutrients are the vitamins and minerals that you need only in small quantities everyday.

Macronutrients are the proteins, carbs, fibre and essential fats that your body needs in greater quantities everyday.

To avoid malnutrition it is important you adopt a highly nutritious bariatric diet that provides the right balance of macro- and micronutrients on a daily basis.

Complications of deficiencies and malnutrition

Let’s look at anaemia

After surgery your risk of developing anaemia increases. A recent article in the World Journal of Diabetes states that 33 to 49 percent of patients develop anaemia within two years after surgery. These figures increase slightly for gastric bypass and RYGB patients.

Anaemia causes fatigue, hair loss, rapid heartbeat, shortness of breath, dizziness, pale skin, leg cramps and insomnia. It also increases the risk of developing complications with unrelated illnesses as anemia slows down the recovery process. Not at all pleasant, anaemia can really bring down the quality of your life after you've worked so hard to improve your health. It's best to take precautions from the start and ask your GP for a blood test if you experience any symptoms.

The primary cause of anemia is iron deficiency and the secondary cause is a deficiency of vitamin B12. Your risk is increased if, after surgery, you develop an intolerance to meat and dairy.

Iron is an essential micronutrient that you body needs to function well. The recommended daily intake is 7 to 18 mg per day and up to 27 grams per day for pregnant women. Most people with an iron deficiency need 150 to 200 mg daily (2 to 5 mg of iron per kilogram of body weight per day).

It is worth noting that sufficient levels of vitamin C are essential for the body to absorb iron. If you think you might be iron deficient then do not hesitate to ask your doctor for blood test.

Which foods to cook?

Hemoglobin-rich sources. Meat, fish and poultry contain hemoglobin which provides the best sources of heme-iron. Take up eating oysters, chicken livers, clams and shellfish which all contain over 3.5 milligrams of iron per serving, and make delicious snacks!

Dark leafy greens. Dense with nutrients and very, very good for you. Kale, swiss chard, collard greens, spinach, long stemmed broccoli, mustard greens, cabbage, watercress, red and green romaine lettuce are good sources of non-heme iron and can be eaten in frequently. Make sure you get at least 3 cups of leafy greens per week.

Let’s look at deficiencies of other vitamins and minerals

Bariatric surgery patients are more likely to be deficient in vitamin, A, K, B and E.

Just over half the patients who undergo a mini gastric bypass, gastric sleeve, BPD (with or without duodenal switch) or RYGB are found to be low on the fat-soluble vitamins A, K and E and thiamine (vitamin B), just two years after the operation.

Symptoms include dry hair, dry eyes, easy bruising, excessive bleeding, nausea and constipation. Some minerals that bariatric patients can find difficult to manage are magnesium, zinc, copper, and selenium. Although the body only requires minerals in small quantities, maintaining healthy levels does wonders for your energy levels, brain function and overall health and well being. Even slight deficiencies and imbalances in these vitamins and minerals can cause health complications that worsen over time.

Which foods to cook?

The fat-soluble vitamins A, E and K are not easily destroyed in a hot saucepan or oven. High sources are found mainly in root vegetables and dairy which digest better when cooked and served alongside other essential fats and healthy oils.

To boost your vitamin A levels go for a combination of whole milk, leafy greens and root vegetables containing beta carotene (carrots, sweet potatoes, squash etc). Combine these ingredients for a delicious, vitamin-fortified, stew!

To boost your vitamin E get to know your healthy oils and make super salad dressings with wheat germ oil (a serving provides a whopping 135 percent of your daily value) to drizzle over your salmon or avocado salads. Sprinkle on some sunflower seeds (66 percent of your daily value) for an added boost!

To boost your vitamin K look no further than kale. When cooked and seasoned well kale is a highly delicious and nutritious addition to soups, stews, roasts, scrambled eggs, pies, and just about dinner recipe! Just half a cup of kale provides a massive 443 percent of your daily value. Cook dark leafy greens with beef liver, pork chops, brussels sprouts and green beans. Go for breakfasts of milk, eggs and cheese - all high in vitamin K.


Did you know that vitamin K is produced by bacteria in the GI tract? Deficiencies are more usual in newborns and in people on antibiotics or anticoagulant drugs.

Let’s look at protein malnutrition

By now you will know all about the important role of protein in the bariatric diet. In order to prevent malnutrition your body needs a daily intake of 60 to 120g of good protein.

Getting enough protein can be a challenge in the first weeks and months after surgery, when eating and digesting adequate quantities is easier said than done. This is why you are strongly advised at each meal to eat the protein source before even your vegetables or carbohydrates. First and foremost your body needs protein to repair and grow new cells.

If you eat a protein-rich bariatric diet and put protein before carbs and sugary foods you will be absolutely fine. Always use protein powder to give yourself a boost on days when you don't received enough protein from your food sources.

With less than 21 percent of patients treated for protein malnutrition, it is more usual for patients to experience micronutrient deficiencies rather than malnutrition.

If you are concerned you have a protein deficiency then please speak to your GP immediately. If left untreated protein malnutrition can result in life threatening health problems.

Which foods to cook?

At breakfast boost your protein intake by swapping toast and cereals for protein rich breakfasts of Greek yoghurt, chopped almonds and pecan nuts, apple slices with peanut butter, scrambled eggs, cold meats and cottage cheese. Protein shakes are also a great breakfast replacement as long they are low in sugar and calories.

At lunch go for hard boiled eggs, fish or cold meats. Cheeses are a good source of protein and go well with cherry tomatoes and salads. Snack on fruit, berries and nuts (especially pistachios!).

At home cook lean proteins such fish, chicken and beef. A serving of grilled salmon with the skin on has around 15 grams to 20 grams of protein, and essential omega-3 fatty acids.

For more food inspiration search delicious protein-rich recipes at Bariatric Cookery and check out Bariatric Whole Living Recipes & Community, a Facebook group by Kirstin Willard, a specialist bariatric dietician.