The Unfiltered Guide to Bariatric Nutrition

The Unfiltered Guide to Bariatric Nutrition


I am a registered dietitian (RD) who has worked with bariatric patients professionally, but I also have had weight loss surgery myself.  This is a blog post about what you or a loved one may experience throughout the process of bariatric surgery, and it is written from a perspective of science, experience, and from a somewhat unfiltered dietitian.

 Disclaimer #1: This article is NOT intended to take place of advice given to you by your program’s practitioner, surgeon, or dietitian.  Each program establishes their own guidelines for dietary advancement, and it is extremely important that you follow your program’s recommendations. 

There are those who may criticize weight loss surgery, and they may even call it “the easy way out.”  But I’m here to tell you that going through a bariatric program might be one of the most difficult things you have ever done. Any well-accredited bariatric program should review labs and vitamin status, and require an EGD w/ biopsy.  The results of this can help the surgeon to determine if one of the procedures will be a better choice for you, plus the biopsy can help discover if there is a bacteria called H.pylori, which can lie dormant and the patient may not even know they have it.  Your program should screen for sleep apnea and may send you for a sleep study. It should require an exercise component, weight loss prior to surgery, psychological clearance, and nutrition clearance.  These last two may take more time to get through, but are also very important, because they will help to create the lifelong changes needed for this surgery to work. 

I’m sure you’ve heard people call the gastric sleeve (AKA the sleeve gastrectomy or the vertical sleeve gastrectomy (VSG)) or the Roux-en-Y Gastric Bypass (RYGB) “a tool.”  This is an accurate description of weight loss surgery.  You will have both restrictive changes (can’t fit much food or liquids in) and hormonal changes (changes in receiving hunger and fullness cues).  Your surgeon should explain all of the surgery options (hopefully with pictures).  Click here to learn about the most common bariatric procedures from the ASMBS.  I know that many of us feel that a surgeon or MD’s time is precious, so we sometimes don’t want to bother them with questions. But any surgeon worth his or her salt, will happily clarify anything so that the patient has a good understanding of the procedure they will be performing. Again, please don’t hesitate to ask your team for further explanation; this is your body and you need to have a full understanding of what could happen with each surgery.  (Beware of what you may learn from social media, this is a very personal choice)

Your RD should help you practice how to eat as a bariatric patient before surgery; meeting protein goals and nourishing yourself with a tiny stomach can be tricky. Your RD will likely require food journaling or tracking in an app; studies show that those who track their food intake are 30-40% more successful at weight loss than those who estimate calorie & nutrient intake.  You should be assigned a calorie, protein, and fluid goal, and these can be challenging to meet both before and after surgery. She or he should also explain the importance of taking specific multivitamins that you will need for the rest of your life.  

And finally, your therapist should be able to help you identify and work around any triggers or even help to establish a healthier relationship with food.  If you weren’t asked to attend therapy, I highly recommend seeking it out on your own. This process can be more mentally draining than people realize, and it is helpful to have someone to talk to as everything you presently know is going to change after surgery.  Essentially, you or your loved one should be seeing a team of people who are there to assist in establishing new, healthier eating patterns to allow you long-term success after the bariatric surgery.

Disclaimer #2: Each person will have a different journey and a different experience with their bariatric surgery.  I will attempt to speak in generalities because you might have a completely different experience than the one I had.  If I learned anything as a bariatric dietitian, it’s that Every Body is Different!

1-2 Weeks Before Surgery: 

Most bariatric programs require a period of liquid diet immediately prior to surgery.  Please follow your specific program’s pre-bariatric diet.  This is a period of rapid weight loss, which can help to shed fat around the patient’s liver.  The liver is a large organ and lies across the stomach which will be operated on, and it must be moved out of the way by an instrument during the surgical procedure.   One of the surgeons I worked with explained it like this: the yellow fat that surrounds a fatty liver is slippery and squishy.  It can cause the liver to sink into or even slide around on the retractor (instrument used to lift it out of the way) and can sometimes get scraped or nicked by the instrument intended to hold it in place.  There are new research studies coming out all the time that argue both for and against the helpfulness of this liquid diet prior to surgery, so it is up to your surgeon as to what his or her preference is. Please follow it.

This is a tough 1-2 weeks, but you got this!  Most programs ask you to drink 3-5 protein shakes/day + allows clear and calorie free liquids, broths, popsicles, and gelatin to help you satisfy hunger.  You will have a full-sized stomach, but many say that the hunger signals subsided after the first couple of days, and they were able to get through it.  What helped me was asking my mom and husband to take over the cooking duties for the family during the liquid diet.  I lit a candle and separated myself from the sights and smells of the cooking food.  I would sit in my room or family room and stream a show and repeat my mantra into my protein shake.  “Totally worth it…totally worth it…totally worth it…”

Immediately after surgery and the first few weeks:  

Your surgeon and anesthesiologist will attempt to take every step to help you with nausea which is a common side effect of anesthesia.  Anti-nausea meds may be given orally before surgery, will be in your IV, a small medication-releasing patch may be placed on your neck, and you will be on an oral anti-nausea regimen post-surgery.  This is one of those things that is highly individualized; for example, I did not have much nausea, and when I did, the dissolvable tab worked just fine for me.  However, the occasional patient does not do well with anesthesia at all.  The anesthesia is heavy and you will be deeply asleep and intubated throughout the surgery.  Most are pretty groggy for the first couple of hours in recovery, but by the time you are brought to your room, we’re hoping you’re ready to walk within the first hour or two, if not right away.

Pain is also highly individualized, as we all receive and process it differently.  Most patients feel pressure and swelling in their upper abdomen, and there can be quite a bit more swelling if the surgeon repairs a hiatal hernia during the operation.  Patients will sometimes report a pulling sensation at the surgery sites when they walk, and I would personally recommend an abdominal binder for support (ask if they can provide you one at the hospital, if not, you can walk into your local medical supply store and buy one off the shelf for around $15-20 or purchase it on-line).  I had the hiatal hernia surgery in addition to the RYGB, and I felt pain and swelling in my lower sternum area; ice packs and acetaminophen helped (I couldn’t wear the binder comfortably until after the swelling went down, but liked it afterward).  Patients often ask me how painful the surgery is, and it’s such a difficult thing to describe, but when I saw that my patient had a c-section, I admitted to them that I had 2 c-sections and this was waaaaayyy less painful than either of those!  (But again, pain is subjective)

During this stage, two of the most important tasks you will need to schedule into your day are walking and drinking.  Walking around the home, down the driveway, or a slow stroll down the block every hour or two will get the blood flowing in your legs and help to reduce the chance of forming blood clots.  You will be on a strict drinking schedule, which usually means aiming to sip 1oz every 15 minutes, for an average of 4oz per hour while awake.  This way there is some leeway if you skip a sip here and there while doing other daily duties.  My program asked me to practice taking small sips before surgery, but nothing could have prepared me for just how tiny my sips would actually be after the procedure!

Along with documenting every ounce of water drank, it is important to track grams of protein.  Your dietitian or another staff from the bariatric clinic will likely visit you in the hospital and go over your goals for the next stage.  Protein is very important, but fluids are the #1 priority this early on.  I tell my patients that it takes a while to become protein malnourished, but you get just a couple of low-fluid days and dehydration can set in quickly.  This is the time to establish a routine of sipping liquids all day, timing when to stop drinking before your next snack or meal, how to time your meals, and when to start drinking again.  By the time you head back to work, you’ll know exactly what to pack in your lunch bag.  These weeks, I often saw patients eating between 450-800 calories. (Remember:  Every Body Is Different)

Note: This is not the time for strenuous exercise, work, or walking/hiking.  This is the time where you should be listening to your body.  Dizziness and feeling light-headed is not okay. It is often related to low fluid or a blood pressure medication that needs to be adjusted, but it can also be something more serious.  DO NOT ignore these symptoms as “all part of the process,” get in contact with your surgical team ASAP.

Months 1-3:

This is a period of tight restriction and most still won’t be able to fit much food in; the majority of the patients I saw at the bariatric clinic were able to intake between 650-900 calories during these months.  You will likely still be dependent on protein shakes (if you tolerate them) and high protein, easy to chew foods like yogurt and cottage cheese to help you meet your protein requirements.  You will find that some foods fit in your stomach more comfortably than others; for example, while you may be able to comfortably eat a 5oz Greek yogurt or 4oz of cottage cheese, you might feel stuffed after just 2oz baked chicken.  Even after the diet is upgraded to “regular,” some people simply do better on meats that are soft enough to cut with a fork, or shredded, or slow cooked for softness. And remember to chew, chew, chew!

I generally recommend that my bariatric patients wait for at least 3 months to add any starchy foods, because they usually add volume with very little to no protein.  The little bit of room in a bariatric-sized stomach at this stage should be saved for the protein portion of the plate then non-starchy vegetables and a bit of fruit, as tolerated.  Most bariatric patients are quite sensitive to sugar and high fat foods this early on, and limiting them is essential to avoid dumping syndrome.  Not only is the gut sensitive to these foods, but there may also be taste changes in the post-surgical patient. 

Unfortunately, a very high protein diet with the only fiber coming from the small amount of vegetables that fit, in addition to struggling to get in 64oz fluid, plus starting your bariatric multivitamin with iron can be a recipe for constipation.  A stool softener can be used at this stage to avoid very painful or even impacted stools.  I don’t usually recommend adding over-the-counter fiber supplements until you are consistently getting in 64+oz, because you need the fluid for proper bulking of these products.  Please don’t hesitate to ask your team for their recommendation.

Note: it is not uncommon to feel periods of exhaustion during this time, because you are in a severe calorie deficit and the actual definition of “calorie” is a unit of energy.  Don’t worry, you will adjust to your new energy intake, and as the weight keeps coming off, you will likely feel as if your energy is boundless!  Also, hair loss will be discussed at the end of the next section.

Months 4-12:

By this time, most bariatric patients will have found their groove and are rocking the bariatric lifestyle. Many are eating between 900-1,200 calories (at least by 8 months – 1 year) and are able to hit protein and fluid goals without much difficulty.  As a rule of thumb, try to stay to 1c. of food at a time to reduce the risk of overeating and experiencing discomfort or regurgitation.  Continue to avoid sugars and highly-refined starches to avoid dumping syndrome.

We tend to be creatures of habit, so the weekdays might be a handful of rotating breakfasts, lunches, and snacks.  I was still struggling with cooking large dinners, and eventually my husband [gently] told me that I need to cook less food because he can only eat so many days of leftover spaghetti.  Getting full so quickly is great though; I recommend packing up half of your meal into a container even before calling the family out to eat.  This will ensure that you have lunch for the next day, where if you leave it out, someone might snag it for themselves. 

You have probably made it through your first holiday meal, where family members watch you place tiny blobs of foods on your plate, and still can’t make it through the whole portion.  It becomes a taste-fest, where bariatric patients often only choose their absolute favorites.  Sure, Aunt Jane might be miffed because you passed on her famous potato salad, or you could only eat 1 teaspoon of Grandma’s famous mac-n-cheese (because the oil from the cheese makes your tummy upset), but they will get used to it.  Sometimes we know our limits, and sometimes we find them out the hard way.

I experienced a mild form of dumping syndrome 2x during these months.  The first time was completely my fault. I decided to have a sliver of no-sugar-added blueberry pie for my birthday. Even though I made sure to avoid eating the crust, I feel that my mistake was putting 1 tablespoon of vanilla ice cream on the top.  That was enough to start my guts a-gurgling.  I didn’t get “the sweats” or shakes, just an urgent need to excuse myself and head to the bathroom.  The second time was with white chicken chili.  I’m not sure if it was from the light cream cheese, the oil from the shredded cheese, or the fiber from the beans themselves, but I had to excuse myself quickly.  However, I have had the same recipe a dozen times since and have never experienced dumping from it again.  

At 4 months, I generally tease my patients as they step on the scale and are beaming ear to ear about their weight loss, by saying “are you cold yet?”  The first winter after surgery can be brutal, you’ve likely never experienced a cold like this unless you were raised in Arizona and decided to spend a winter in Minnesota!  I recommend picking up an electric blanket or mattress pad, preferably one with 2 zones, because your partner is going to think you’ve lost your mind!  It’s more than just having “less insulation;” there is also a bit of a metabolic slow-down in the immediate months after bariatric surgery1,2, which is likely related to a severe calorie deficit, quick and sustained weight loss, and the inevitable loss of muscle tissue. 

Yes, we do lose some lean muscle tissue, even if we hit our protein goals consistently.2  Around 1 year post surgery, I asked patients if they experienced any muscle loss (or feel like they are not as able to lift heavy items as they were before surgery).  I cannot think of a single patient who told me that they didn’t lose at least some upper body strength.  I also can’t think of a single patient who thought this minimal loss was not worth it overall.  If you haven’t started lifting weights by 1 year, I would highly encourage you to start rebuilding the muscle tissue.  This will help your body to be more shapely, will help to recover your resting metabolic rate (muscle burns more calories), and might even make you tolerate the cold better.  But did I mention how much better summer weather is post-surgery?  Say goodbye to “Sweaty Betty” and hello to tolerating hot weather!  Yay!

Not everybody who has bariatric surgery will experience hair loss, but the majority of us do on some level. If hair loss is experienced after surgery, it is usually most noticeable between months 3-6.  Some folks with thicker hair hardly notice a change, while those who were already experiencing some thinning prior to surgery tend to notice it the most during this phase.  I was thinning since my early 30’s, possibly due to type 2 diabetes or PCOS (I had them both), so I felt like I was “hit hard” with the hair loss.  At the 3 month visit, I recommended patients to purchase a “shower daisy” to help avoid having to call a plumber to snake the hair out of the drain.

 I was obsessive about cleaning all the hair out of my hairbrush prior to brushing so I could monitor the loss.  The major hair-shedding started slowing down at 6 months, and by 9 months my hairdresser was finding “new baby hairs” (though I suspected they were broken because I have always had fine, fragile hair).  I’m sorry to say, but if you are one who experiences this, it might happen even if you hit all your protein and fluid goals and take your bariatric vitamins religiously.  All surgeries are considered a traumatic experience for your body, but bariatric surgery results in a sudden drop of calories, which causes the body to burn its stored fat as fuel.  This deprivation is another trauma; our hair is often a tattletale of what is going on inside our bodies.  But I can tell you that those who are not meeting protein goals and don’t take their vitamins consistently suffer much more muscle and hair loss than those who do.  Is it worth it?  In my opinion, hell yes!

18 months – 3 years:

Hello plateaus!  Okay, in all honesty, there will be plateaus throughout this entire journey.  Some experience them very early (no weight loss between the 2 week post op visit and the 1 month post op visit can be mentally devastating, but trust me… I see it all the time… you’re nowhere near being done losing!)  Oh, and it never comes off as fast as we want it to either.  By this stage, you’re an old pro!  You have recipes saved from Pinterest, you might be in Facebook groups or watching your favorite post-bariatric TikTok’er sharing their favorite low-carb recipes.  You know all about the low carb tortillas, the cloud bread, lavish bread, substitutions for pizza, cauliflower rice and mashed potatoes, protein puddings and ice cream, and all the low-fat-yet-keto-friendly replacements for all your favorite foods!

Some choose to take a break from tracking their calorie intake on their app, saying “I eat the same thing all the time” or “I run a head count of my protein intake and I hit it every day.”  This is okay, however, I would recommend that nutrition tracking is resumed any time there is a prolonged plateau or weight loss has stalled indefinitely.  Studies show that people tend to underestimate the calorie content of foods, even if they have been doing it for a long time. And it can be quite challenging to stay around 1,200 calories,  especially if you are able to tolerate most foods.  By the second and third years, it might be harder to keep to only eating 1c. of food (since vegetables are fluffy, I give them some leeway or imagine them smashed into the cup to remove the “air space”)

Most surgery centers use an app or formula to calculate how much weight they predict that you will lose, based on several pre-surgical factors.  The prediction assumes most of the weight will come off in the first year, then a few more pounds will come off the second year, and then will settle a couple of pounds up in the third year.  This is just a prediction, if it isn’t as much as you were hoping, you can make it your mission to “blow the calculator out of the water.”  You can continue to lose weight after the first couple of years, but it doesn’t come off as fast or, in my opinion, as easily.

I do recommend monitoring your weight at least weekly so you’re able to catch any increases and do a course correction before the favorite new jeans are too tight.  I also warn to not allow the scale to dictate how you should feel about yourself.  If you are working out and building strength, don’t expect the scale to go down during anabolic muscle building! Rather, let your clothes or tape measurer show you the evidence of your hard work! 

By this point, most food intolerances have subsided.  For some, you can eat almost everything without any repercussions.  Ice cream upsets my stomach to this day (Thank God!  I had a real problem with overeating ice cream prior to surgery), I can enjoy a little bit of fried food but have decided that some things just aren’t worth it.  Because of the small stomach capacity, I have learned to rank foods into categories.  Meat always ranks high because I need the protein and genuinely enjoy it.  I, personally, have let the potato go.  Potatoes of any sort used to be my favorite food, but now I am usually happy with just a taste because they take up too much “real estate” in my pouch.  This is the same for noodles, I generally enjoy the meat and sauce more anyway. 

Remembering that “every body is different,” some have reported ongoing intolerances which can sometimes last forever.  When a patient reported that she was over a year out and still couldn’t eat salad, I felt so bad for her!  I love me a good salad!  Every once in a while, meat will catch  me off guard, especially if it’s more tough or dry (like chicken breast); it felt like I had swallowed a rock!  It took nearly 15 minutes for the pain to subside.  This is a rare occasion for me, and I suspect that I was eating too quickly and didn’t thoroughly chew before swallowing.  By this time post-surgery, most are back to the daily grind and taking 15-20 minutes to eat our meal has gone by the wayside.  Remember those important tips to slow down your mealtime: take a bite, put down the fork, chew each bite 20x, set a timer, have a conversation, etc.  

Year 4 to forever:

Take a moment to revel in how far you’ve come!  Keep those pictures of your journey where you can find them.  Whether you are continuing to work on your physique or are in permanent maintenance mode, always remember the basics of bariatric eating: water, protein, vegetables & fruit, vitamins, exercise.  But here’s the thing… I have mentioned that Every Body is Different multiple times throughout this blog post, well this is where we all get off the journey and follow our own destination.  Some are perfectly happy with their new bodies, some are starting to feel like it’s time to stop the weight loss because they feel they are becoming too skinny, and some still wish to lose more weight.

Not only is every body different, every personality is different.  I follow some bariatric groups on social media, and I see the same debate come up over and over.  That is: can you eat whatever you want as a bariatric patient in the maintenance phase?  Some believe that you can because your stomach has such a small capacity, so why restrict yourself from enjoying food and, essentially, life?  But I feel that there are more of us out there who “remember where we came from.”  Some of us are not completely sure that we can allow ourselves to eat the foods which caused us to become obese in the first place.  We fear that we might not have the self-control to stop after a couple of bites or at the first sign of feeling satisfied or full.  I came from a family that regularly used the phrase, “Mmmmm…this tastes like more!” 

I once heard someone say that weight loss surgery is “surgery on your stomach, not your brain.”  In other words, it’s a tool which is designed to help you to feel full quicker, so if hunger is your main issue, than this is the fix.  However, if you’re anything like me, my appetite is often correlated to my mood, stressors, hormone cycles, celebrations, events, childhood memories, etc.  My sense of smell can be a trigger, visual enticements like billboards or ads, even driving to certain places can make me crave certain foods, hell… food can be a trigger itself!  If it tastes good, I might just continue to eat it until I’m uncomfortable. I admit it, I’m a foodie!

If you are highly disciplined and know your limits, or have a high metabolic rate, or had a very malabsorptive surgery and the weight keeps falling off, then by all means, indulge!  (Still hit your macro & micronutrient goals to keep healthy though) But for the majority of bariatric patients, I caution to keep an eye out for sneaky calories.  The easiest way to blow calories is through sweetened (or alcohol-containing) beverages, because these go down easy without much resistance or restriction.

 Another way to blow calories without even realizing it, is snacking on foods which are calorie dense.  Calorie dense foods are small, but pack quite a calorie punch.  For example, 1 little tiny tablespoon of peanut butter is 90 calories.  Have you ever tried to spread 1Tbsp of PB onto a celery stalk?  It won’t even reach the end!  This is why PB is one of the most recommended foods to help people to gain weight without eating unhealthy junk.  Nuts and seeds are wonderful for you because they contain fats that are beneficial for your heart and brain, but make sure you budget for those items.  I used to love putting sunflower seeds on my salads until I discovered that they are 114 calories for 2 Tbsp (and I was putting more like 1/4c. on my salad, 227 calories).

Some of these calorie dense foods are actually good for you, so they aren’t “no-no’s,” we just want to make sure they don’t put us way over our calorie limit and cause re-gain.  Here’s a list of some common toppings or treats that can quickly add up: Avocado or guacamole, chia seeds, granola, trail mix, dried fruit, salad dressings, cheese, hummus, overnight oats, full fat yogurt or dairy products, MCT oil or bulletproof coffee, etc.  Now if you’re ready to stop losing weight, I’m going to tell you to eat these items because they won’t take up much room in your stomach, but will add much-needed calories.

To conclude this lengthy post, whatever you choose, whether you decide to pursue bariatric surgery or try other methods first.  Or maybe you’ve already had the surgery and simply want to see if this is anything like your journey.  I wish you all the luck and happiness!  I hope my unfiltered take on this personal subject didn’t scare you too much or gloss over any important points.  There are too many facts and stories to include in one post, so please keep looking for new topics and stories to come.  Please continue to support each other, it’s tough out there. 

Works Cited: 

1. Nutrition care in bariatric surgery. EAL. Accessed March 27, 2024.

2. Chu L, Steinberg A, Mehta M, et al. Resting energy expenditure and metabolic adaptation in adolescents at 12 months after Bariatric Surgery. OUP Academic. February 11, 2019. Accessed March 27, 2024.

Add Your Heading Text Here

Leave a Comment

Your email address will not be published. Required fields are marked *

Scroll to Top