Bariatric Macros

The Scoop on Macros and Bariatric Surgery eating

Updated February 2024

Macros is a term commonly used in eating plans. It is short for macronutrients. Different plans will recommend what percentage of fat, protein and carbohydrates your calories should come from. What about bariatric surgery patients? What are bariatric macro guidelines?

We’ll talk about it more here.

Blog series: Popular Diets and Weight Loss Surgery

Read the recap blog for the Popular Diets after Bariatric Surgery Series here including a full comparison chart!

The Scoop on Bariatric Macros

As I’ve asked what post-op patients want to hear about when it comes to popular diets and bariatric surgery, the topic of macros came up quite a bit.

I thought I’d start here because there are a few diets going forward that will use macros within the structure of the eating plan. A good conversation around macros will help us before we jump over to eating plans like keto.

“Macros” is an abbreviation on the word macronutrients. 

In the world of nutrition we have macronutrients and micronutrients.

Micronutrients are vitamins and minerals. The ASMBS provides a list of recommend micronutrients for post-op patients and dietitians will then recommend a vitamin routine that will fulfill that.

Macronutrients include protein, carbohydrates, fat and water.

Our bodies need these nutrients in larger quantities and we need all of them. The ratio of how much of each is unique to the person, their health goals, their conditions and more.

Working with a Registered Dietitian allows you to better refine your macronutrient percentages based on your specific needs.

What macros should a bariatric patient be eating?

If only it were that easy! Right?!

Nutrition has never been simple and while it seems bariatric surgery nutrition should be “standard” it still has a ton of variables.

Every program will have their differences in their approach and some may not use macros at all in their nutrition counseling.

I will share my approach to macros for post-op patients as well as a few other approaches from other professional groups.

Sometimes it seems the first step in comparing and contrasting diet plans is to see what approach it’s really focused on. Some programs will build around macros (how much protein, carbohydrate and fat is advised on the plan). However, other plans may look only at calories and another plan tell you not to count anything but focus on eating quality food and listening to you body’s natural cues.

Some programs will use points (WW) and some will use the visual of a plate (Bariatric Plate Method).

All this to say, the question “what macros should a post-op be eating” is going to differ. Your dietitian or program may have a fundamental “approach” to the eating plan based on their philosophy of how to manage weight.

Some patients may have more vigorous exercise or other lifestyle factors that might warrant different macros.

Next I will cover the macros as I approach them but this is my chance to remind you there is incredible value in working with your dietitian for an individual plan that fits you best and feels most sustainable. Feel free to ask them “why?” to better understand the root of their approach.

Bariatric Food Coach Approach to Macros

As previously mentioned, it is going to differ but as a general starting place I like patients to focus on eating two bites of a lean, solid protein to one bite of a fibrous, fresh vegetable. Take small bites, pause in between bites and stop at the first indication of fullness.

Here is a visual of a plate with my 2:1 Protein Method.

When it comes to macros, this tends to work itself out around 50% protein, 20-25% carb and 25-30% fat.

NOT every day is perfectly in line with these numbers.

I like to use the macro pie chart to assess things at the end of the week or a month to see what might be surprising. 

This is my approach to not stressing every calorie or gram you eat but instead focusing on good quality food, listening to your natural cues and food journaling to review how things are going.

Macros are a way to check in (like looking over our budget) for what pivots you might want to make.

If someone is finding themselves stressed about the numbers, I might tell them to switch to a paper journal and just focus on quality lean protein and veggies and not stress the numbers.

Some research supporting MY APPROACH

There is no standard to eating after bariatric surgery. Registered Dietitians will use research, knowledge and experience to determine what might fit the goals of each patient.

My favorite piece of research on this particular topic was a poster at an ASMBS Annual Meeting.

Bariatric Support Centers International published a poster entitled “Factors Distinguishing Weight Loss Success & Failure at 5 or More Years Post-Bariatric Surgery” which summarized behaviors of highly successful patients and not highly successful patients. (Below is an image of the poster and clicking on the image provides the PDF.)

Under the results section you will see percentage of calories from protein for highly successful patients was 49%.

The percentage of calories from carbs was 31% and the percentage of calories from fat was 20%.

They also summarize behaviors such as eating protein first, eating fast food weekly, eating in front of a TV and more.

What other bariatric professional groups say about macros

For bariatric professionals, we have access to a few professional groups that provide great research and education. Certainly information is always arising in the field of obesity research and bariatric surgery so we have to keep up.

One more recent publication from the Surgery for Obesity and Related Disease in 2020 provided a chart that compared four professional groups and their diet recommendations for bariatric surgery patients. I will do my best to summarize.

The Academy of Nutrition and Dietetics (of which I am member) does not provide specific guidelines on protein, carbohydrates and fat. Their handbook includes how the dietitian can calculate protein needs for the patient and values clinical judgement for the provider with each patient.

The ERAS Society (Enhanced Recovery after Surgery) recommends patients have 60-120 grams of protein a day and does not specify carbohydrate or fat.

The 2008 ASMBS Allied Health Nutritional Guidelines states exact protein needs have yet to be defined and also does not specify carbohydrate or fat.

UpToDate postoperative nutritional management does provide guidelines for macros more than any of the others, although I find them high in carbohydrates.

They recommend 46 grams of protein a day for women and 56 grams a day for men (10-35% of the diet from protein). They recommend 50 grams of carbohydrate a day for early post-op (not defined what early post-op is) and as diet increases 130 grams of carbohydrate a day. Fat is 20-35% of total intake.

This makes their macros (for the further post-op patient) roughly 43% carbohydrate for a 1200 calorie a day diet.

All of this is to say there is not a standard macro recommendation from bariatric professional groups and a lot is left for the dietitian to work with the specific patient on what fits their lifestyle and goals the most.

Factors that may change macro recommendations

There are certainly times when a dietitian will recommend different macros for a patients individual situation.

The two main reasons include pregnancy and for a highly active patient with specific goals for strength or endurance training.

For a patient focusing on strength, protein goals will continue to be the focus.

For a patient with an endurance event such as a half marathon, they will need more carbohydrates. Working with a dietitian is especially helpful for times of exercise training. Here is a members video course on Exercise and the Bariatric Diet. 

For pregnancy, complex carbohydrate would be added to the meals. Here is a blog series on pregnancy. 

More in the Popular Diets Series