macros after bariatric surgery

Focusing on Micronutrients & Macros After Bariatric Surgery

September 13, 2017

What is a calorie? Every week I teach a Fundamentals of Nutrition Class at Lenox Hill Hospital in New York City and I start with that question. What does the word calorie mean? As that question lingers in the air, confusion begins to enter the room and patients hesitantly respond ranging from calories are fats to calories are bad things found in food or even not knowing what a calorie is.

What is a calorie then? Calorie means energy, the amount of energy the food provides for the body. Certain nutrients such as our macronutrients (carbohydrates, protein, and fats) all provide energy for our body to function properly day by day. For example, 1 gram of protein and 1 gram of carbohydrate provides 4 calories, while 1 gram of fat provides 9 calories.   

On the Nutrition Facts Label, you will find macronutrients measured in grams instead of milligrams. This means that your body requires a greater amount of protein, carbohydrate and fat for survival as compared to your micronutrients. Micronutrients (vitamins and minerals) do not provide energy for bodily function; however, they act as co-enzymes for the production of energy during the metabolism of our macronutrients.

The Word Calorie Is Not A Bad Word!

Guess what, the word calorie is not a “bad word!” Yes, a reduced calorie diet is essential for weight loss and maintenance along with adequate physical activity, however, focusing on the quality of the calorie is as important as the total number of calories consumed each day.

Quality calories are calories that provide functional benefits to the body that contain a mixture of both macro and micronutrients. For example, functional benefits of protein foods (dairy, eggs, fish, meat, and poultry) include wound healing and maintenance of lean muscle mass. Functional benefits of complex carbohydrates that provide fiber (oats, sweet potato, beans, and lentils) include controlling blood sugar levels and improving digestive health. Finally, functional benefits of unsaturated fats (olive oil, canola oil, and avocado) include lowering blood cholesterol levels and reducing inflammation.

Nutrition After WLS Isn't One Size Fits All

Counting calories, or grams of macronutrients per day, is not a “one size fits all” approach.

Today, there are many applications and websites that can help count total calories and macronutrients. Popular apps include: MyFitnessPal, Lose it, Fat Secret, Cron-o meter, and SparkPeople. Government resources can also be used such as the USDA Food Composition database. However, these resources can be confusing to work with, without knowledge of what serving sizes look like. Therefore, seeking guidance from a registered dietitian prior to using these applications can help establish a foundation of how to count calories and what those calories look like per meal. Each patient, depending on their needs and goals should also work with a registered dietitian to understand what macronutrient breakdown works best for them.

For example, a patient who is one year out of surgery and who is looking to gain muscle mass will have a higher need for protein. The source of protein consumed is also an important factor when speaking about how the protein will be absorbed. The amount absorbed by the body is based on the bioavailability of the protein.

Bioavailability is simply the rate at which our bodies can use these proteins.

For example, animal sources of protein have a higher bioavailability than plant sources. However, saturated fat is a concern with large amounts of animal proteins, therefore a variety of both animal and plant proteins should be included for a well-balanced diet. On the other hand, a bariatric patient who is training for a marathon would have a higher need for carbohydrates. This would help provide instant energy during long races.    

Carbohydrate intake seems to be controversial when it comes to weight loss and weight maintenance. However, according to the current dietary reference intakes (DRIs), an intake of 130 grams of carbohydrates per day provides the necessary amount of glucose to the brain for normal function, without the need to break down protein and fats for new glucose production (Faria et al., 2013).

The breakdown of protein and fats in the body to produce new glucose when inadequate carbohydrates are available is called gluconeogenesis.

Gluconeogenesis allows the body to preserve its protein stores when an adequate of carbohydrate is consumed. Carbohydrates should be limited, but not excluded, to maintain normal cell activity.

The American Diabetes Association (ADA) also recommends a minimum of 130 grams of carbohydrates per day to maintain normal cell function, while the World Health Organization (WHO) recommends a minimum of 50g per day. Consumption greater than the recommended amount in bariatric patients may lead to an increase in triglyceride levels in the blood and slowed weight loss. Researchers have found that a maximum of 120 grams of carbohydrates per day in post-bariatric patients resulted in greater weight loss and a decrease in triglycerides in the blood (Faria et al., 2013).

The Quality Of The Carbohydrate Is Important

The quality of the carbohydrates consumed is of utmost importance to aid in further weight loss. The glycemic index (GI) of foods should be considered when developing a meal plan for post bariatric surgery patients.  The ADA defines GI as the measure of a carbohydrate food that raises blood sugar levels as compared to a standard. The standard is typically 50g of glucose or white bread.

Foods with a high GI include white bread, bagels, short grain white rice, potatoes, white pasta, pretzels, crackers, melons, and pineapple. These foods raise glucose levels in the blood, which in turn raises the amount of insulin in the blood. An increase in circulating insulin in the blood leads to a higher risk of excess calories to be stored as fat (Faria et al., 2013).

However, low GI foods such as oatmeal, whole grains, non-starchy vegetables and fibrous fruits cause lower increases in blood sugar. Low GI has been shown to increase satiety and decrease overall energy intake, which supports weight loss and weight maintenance (Faria et al., 2013).

For continued positive results, registered dietitian nutritionists (RDNs) working with pre and post bariatric surgery patients should carefully discuss the distribution of macronutrients and their role in maintaining health and promoting weight loss.  This clarity will help educate you on the importance of variety from all food groups in your diets to achieve long-term weight loss success.


Dietary Guidelines after bariatric surgery. Retrieved from

Exercise and the institute of medicine recommendations for nutrition. (2005, August.) Retrieved from

Faria, S.L., Faria, O.P., De Almeida Cardeal, M., Rodriguez de Gouvea, H., Buffington, C., & Furtado, M. (2013.) Recommended levels of carbohydrate after bariatric surgery. Bariatric Times, 10 (3,) 16-21.

Glycemic index and diabetes. (2014, May 14.) Retrieved from

Michelle Liz


Michelle Paillere, MS, RDN, CDN is a graduate from Long Island University, LIU Post campus.  She completed both her Bachelor’s and Master’s degree in Nutrition at LIU Post. Michelle joined the Northwell Health system at Lenox Hill Hospital in New York as the Practice Dietitian for the Department of Surgery in August 2014. There, she conducts weekly Nutrition classes and leads monthly support groups.

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