Your Guide to Daily Calorie Intake After Metabolic and Bariatric Surgery

Your Guide to Daily Calorie Intake After Metabolic and Bariatric Surgery - Bariatric Fusion

Guest blog by: Lillian Craggs-Dino, DHA, RDN, LDN, CLT

After metabolic and bariatric surgery, your journey involves increased attention to nutritional and lifestyle choices, specifically protein, fluids, and vitamins. These important decisions come with any weight loss journey; however, less information is given regarding how many calories you should consume after metabolic and bariatric surgery. 

In this blog, we discuss how to calculate your caloric needs and offer a basic guide on portion sizes to promote overall health and wellness

Understanding Daily Calorie Needs

Understanding the relationship between calorie needs and weight loss is crucial. It's true that everyone's calorie needs differ based on factors like age, sex, size, and activity level. However, it's important to know the principles of a calorie deficit and weight loss may not be immediately applicable in the initial months of your bariatric journey. 

During the first few months post-surgery, daily calorie intake often falls significantly below 1,000 calories and may not even meet your Resting Metabolic Rate (RMR), also known as the number of calories your body needs while at rest to perform essential body functions.  

Metabolic Impact and Weight Loss

The metabolic effects of surgery and a high-protein diet are the primary contributors to weight loss. Nevertheless, as you progress on your weight loss journey and engage in more physical activity, tolerate a broader range of foods, and approach weight loss goals, calorie intake typically increases for weight maintenance. Research shows that, at the five-year mark post-op, caloric intake exceeds 1,500 calories per day.1 

What Are Calories?

What exactly is a calorie, and why is it significant? A calorie is defined as a unit of energy. We often associate calories solely with the energy derived from food and beverages. When we have a daily calorie deficit, consuming fewer calories than needed typically leads to weight loss

However, the term “calorie” also refers to the amount of energy required by the human body for basic bodily functions to survive. This is known as Resting Metabolic Rate (RMR) or Basal Metabolic Rate (BMR), representing the majority of daily calorie needs. As you become more physically active, your calorie requirements to maintain a specific weight also change. 

Calculating Caloric Needs

A reliable way to determine your RMR involves a measurement through indirect calorimetry. If you do not have access to this, predictive equations like the Mifflin-St Jeor are used to determine caloric needs. This equation takes into account factors such as height, weight, age, gender, and activity level. Once your calorie needs are determined, a tailored diet and menu plan can be created to meet your goals. 

Self-Monitoring and Macronutrients

Promoting a healthy lifestyle involves keeping a close eye on what you eat. The trio of macronutrients—protein, carbohydrates, and fats—plays a key role in determining your overall calorie consumption. It’s important to note that both fats and carbs are essential in a balanced diet

When we talk about fats, we mean the healthy fats found in nuts, seeds, avocado, and salmon. Similarly, when discussing carbs, we’re referring to nutrient-rich choices like fresh fruits, vegetables, and whole grains—steering clear of baked goods and sugary treats.

For those who have undergone metabolic and bariatric surgery, it’s crucial to pay attention to your natural portion control system, which is your newly created stomach pouch. Familiarizing yourself with appropriate portion sizes is essential for maintaining a healthy post-surgery routine. Find a helpful guide in the table below, illustrating typical portion sizes. 

Table 1: Food Group Portion Sizes


Portion Sizes


1 cup raw leafy veggies

½ cup cooked or other nonleafy raw veggies

6 oz. vegetable juice

(1 serving of vegetables = 25 calories)


1 medium whole fruit 

½ cup chopped, cooked, or canned fruit

6 oz. fruit juice

(1 serving of fruit = 60 calories)


1 slice of 1 oz. bread

1 oz. ready-to-eat cereal 

½ cup cooked cereal, rice, or pasta

(1 serving of starch = 80 calories)


1 cup milk or yogurt (nonfat preferred)

1-1/2 oz. natural cheese or 2 oz. of processed cheese

1 whole egg

(1 serving of fat-free milk = 90 calories)


½ cup cooked 

Include beans and pulses as part of the starch serving 

(1 serving of beans = 80 calories)

Nuts/nut butter

2 Tbsp. nut butter 

1/3 cup nuts 

Count nuts and nut butter in the fat category

(1 serving of fat = 100 calories, like a slice of high-fat meat!)


1 oz. of cooked lean meat (poultry, seafood, and lean cuts of red meat preferred)

(1 serving of lean/medium/high-fat meat or meat substitute = 55/75/100 calories)


In conclusion, monitoring the amount of calories you consume becomes crucial as a part of self-monitoring to reach weight loss goals

If you want to accurately determine how many calories you need in a day, consult with your healthcare team or registered dietitian to perform an assessment and provide assistance on meeting your calorie goals with a balanced diet and healthy eating habits.


1. Moize V et al. J Acad Nutr Diet. 2013;113(3):400-410.

This blog is for information and education purposes only. This information is not intended to substitute professional medical advice, diagnosis, or treatment. Please consult with your bariatric surgeon or another qualified healthcare provider with any questions in regard to a medical condition. A qualified healthcare professional can best assist you in deciding whether a dietary supplement is suitable based on your individual needs.

Dr. Lillian Craggs-Dino is a retained consultant for Bariatric Fusion.

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