6 Month Diet Before Weight Loss Surgery: Do’s and Don’ts

Have you been wondering what to do to prepare for weight loss surgery? This article gives you all the details on implementing a 6 month diet before weight loss surgery.

Including all the important do‘s and don’ts to be successful in adopting lifestyle habits that will help you maximize your weight loss after surgery and keep it off.

overweight woman, prepping salads at a kitchen counter

Why Focus on a 6-Month Diet Prior to Weight Loss Surgery?

Medically supervised weight loss is often required before approval for bariatric surgery. This could be dictated by insurance requirements or by the weight loss clinic’s team. 

This requires consistent check-ins (weekly, bi-weekly, or monthly) with the weight loss center’s team to ensure you are making healthy lifestyle changes in preparation for surgery.

I’m very familiar with this process as I worked as a Registered Dietitian from 2015-2022 for the University of Washington Center for Weight Loss and Metabolic Surgery

I spent time helping patients prepare for surgery by providing nutrition recommendations and monitoring their dietary changes and progress post-surgery. 

Those who were the most successful with losing weight and keeping it off after surgery were often the ones who put forth the time and effort to make changes before surgery. 

A 6-month diet is the main component of the medically supervised weight loss requirement. It’s a time to focus on making healthy lifestyle changes, which include diet and exercise. 

Many programs require you to meet with a registered dietitian and or nurse or doctor who specializes in providing nutrition education. Your weight will also be tracked. 

Although this requirement may put off some patients, most will find value in this extra time and care spent preparing for surgery. 

Weight loss surgery itself is about changing the anatomy of your stomach, usually through sleeve gastrectomy or roux-en-y gastric bypass. This helps reduce the portion of food you can eat in one sitting to reduce your overall calorie intake. 

The surgery also changes your body’s hunger and fullness signals. So you will feel full from smaller amounts of food and be hungry less often throughout the day. 

Surgery does NOT change your brain. You will have to make consistent efforts to change habits, habits won’t automatically change just because you had surgery.

Taking 6 months to change your habits around food is instrumental in being successful with losing weight and keeping it off post-surgery. Plus it will really minimize your risk of complications after surgery. 

As you get closer to surgery, you’ll want to follow my 3 Month Pre Bariatric Surgery Diet to be sure you are adopting all the habits needed before surgery.

Below, I will walk you through what this 6-month diet before weight loss surgery looks like. 


Do’s for your 6-Month Diet Before Weight Loss Surgery: 

Make sure to implement the following 6 tips as you optimize your diet and lifestyle to prepare for bariatric surgery.

Prioritize Protein

Protein is essential after surgery. Not getting enough can lead to muscle wasting, fatigue, hair loss, and decreased weight loss. 

It’s important as you prepare to be able to answer the following questions:

  • Where are you getting protein from in your diet? 
  • How much protein are you getting? 
  • Are you getting it throughout the day with each meal and most snacks? 

It’s typically recommended that about 20-30% of your calories come from protein. For a 1600 calorie diet, this equates to 80 – 120 grams of protein. Consider that 1 ounce of beef, fish, chicken, etc, is about 7 grams of protein. 

Eat Small Meals Often

This will curb your appetite throughout the day, making it easier to resist the donuts in the breakroom or the cookies at the coffee stand. It also makes it easier to stick to smaller portions if you know you can eat again in a few hours. 

This is great practice for how you will need to be eating after surgery. 4-6 small meals/snacks throughout the day. Something every few hours. 

Your stomach won’t be able to hold much food after surgery, so portions will be much smaller after surgery (about ¼ cup at first). 

No need to eat that small of a portion before surgery. 

For now, just try to reduce portion sizes. Switch out your dinner plates for salad-sized plates and try not to go back for seconds. 

Stay Hydrated 

Drink your water throughout the entire day. 

When you’re thirsty, your body might trick you into thinking you’re hungry. So ensuring you’re getting in enough water (64-100 ounces for most people) can help you consume fewer calories. 

Plus it will only get harder to get enough hydration after surgery. 

You won’t be able to drink with meals, chug water quickly, or drink more than 4 ounces at a time. 

So, if you’re already struggling to get that 64 ounces without these restrictions, then you’re really going to need to work hard to increase your intake now so it’s not out of reach after surgery. 

Dehydration is the most common reason people return to the hospital after surgery. You definitely don’t want that. 

Limit Added Sugar

Sounds easier said than done I’m sure. Work slowly to decrease your intake. 

Your first goal may be to limit sweets to just one serving per day. 

The following week, you may try for just one serving every other day, and then just one per week. 

Sugary drinks especially need to go. Sweets after surgery will likely cause dumping syndrome, and they are obviously going to hinder your weight loss. 

Find ways to distract yourself from these cravings. After dinner, go for a walk or call a friend instead of grabbing a piece of chocolate. 

Indulge in a bowl of fruit when a sweet tooth comes along, or try some new recipes that don’t include added sugars – like ice cream made from blending frozen bananas and cocoa powder. 

Building new habits now will help you be more successful after surgery. And luckily after surgery, it is often much easier to avoid. 

Not only will dumping syndrome turn you off from sweets, but many patients report that their taste buds change, and things that are sweet taste even sweeter – too sweet. 

Eat Mindfully

This means actually chewing your food and taking time to sit down and eat. 

Start by making a point to eat at the table without distractions. That means phone on silent or in another room, TV off, and no computer in front of you. 

Pay attention to how you feel eating. Aim to stop eating when you feel content, not completely full (a 7 out of 10 on the fullness scale, where 10 is Thanksgiving full and 1 is hungry). 

Leave a bite or two of food on the plate to get used to the idea that you don’t need to eat every single thing on your plate. 

After surgery, that habit will get you in big trouble, so work to break it now. 

Aim to start each meal with mindful eating. Being present, tasting your food, chewing your food, and honoring your body’s signals of hunger and fullness. 

Identify Reasons for Eating

Identifying reasons for eating, other than hunger is the first step to making changes to emotional eating patterns. 

Start an eating journal and write down when and why you eat. 

If you find you are often eating for emotional reasons, you’ll need to put into practice alternative things to manage those emotions besides using food. 

You need to create new pathways in your brain to develop new habits. So if every time you’re feeling sad and then you eat to feel better, that becomes a strong neurological pathway. 

This means your mind and body get used to it, and it becomes almost automatic that when you are sad, you’re going to eat to manage that emotion. 

Make a list of things you can do to deal with those emotions besides eating:

  • Call a friend
  • Go for a walk
  • Organize your closet
  • Garden
  • Crossword puzzles
  • Listen to music
  • Make a photo album

Then, try those things out. See what works. 

Next time you’re sad (or insert another emotion) go for a walk, listen to music, color, etc. 

Over time, this will create a new pathway in your brain, making it easier to avoid food and, instead, turn to a healthier alternative to manage this emotion. 

Give yourself the next 6 months to make this change, as it takes time and a lot of effort initially. You’ll find the more you practice, the easier it gets. 

Don’ts for your 6 Month Diet Before Weight Loss Surgery: 

In addition to the do’s above, this list of don’ts is important to implement in your preparation for weight loss surgery.

Don’t Eat Post Surgery Portions Yet

You don’t need to try to eat ¼ cup portions of food already to prepare. 

This isn’t necessary; it’ll just make you super hungry all the time. And it’s super difficult to get all the protein and nutrients you need to be healthy and ready for surgery.  

Don’t Lie to your Dietitian or Doctor

Although trying to look like the perfect student might be tempting, this will only hurt you. 

Your medical team is looking out for your best interest and needs to know how they can best support you. 

So, if you are struggling to reduce your sugar intake, let them know. Let them know if you are unsure how to fit in enough protein. 

Being honest about your struggles will help you overcome them so you can be successful post-surgery. 

Don’t Forget the Exercise

Establishing a routine with exercise will make it much easier to stick to an exercise routine post-surgery. See what works for you now. 

Aim for averaging 30 minutes daily. 

This could be a brisk walk, a workout video, a dance class, yoga, or whatever gets your heart rate up for a consistent amount of time. 

I’ve seen that those who are most successful in losing weight after surgery and keeping it off are those who prioritize exercise. 

Patients who come back to the clinic for their 9 or 12-month post-op visit with no further weight loss or even weight gain are often those who are not regularly exercising. 

Don’t Worry about ALL the Vitamins Yet

Yes, there will be extra nutrient needs after surgery and a list of supplements you’ll need to purchase. 

For now (with approval from your doctor), you can start a complete multivitamin with minerals and some added Vitamin D. 

That’s usually all you need while preparing for surgery unless you have labwork done that reveals further deficiencies. 

After surgery, it will be a different story as your nutrition needs will increase since your food intake is decreased and your ability to absorb certain nutrients efficiently decreases. 

Be sure to always check with your dietitian or doctor for what they recommend. 

Don’t Drink Protein Shakes for Every Meal  

You don’t want to get burnt out on protein drinks when you’ll likely have A LOT of them those first 2 weeks after surgery. 

Substituting one meal for a protein shake is perfectly fine. This will allow you to find an option that you enjoy that works well for you. 

For the rest of your meals, focus on getting protein from real food sources like chicken, turkey, eggs, fish, tofu, beans, etc. 

Remember Why these 6 Months are So Important

Taking advantage of the time leading up to surgery helps establish routines that will ultimately make you successful with your post-surgical outcomes. 

This includes limiting the risk of complications, losing weight, and keeping the weight off. 

Go into it knowing that this will be a lifestyle change and the change starts BEFORE the surgery. 

It’s like practicing for game time. Consider the next 6 months of your practice time. 

Time to make mistakes, learn from them, and get assistance in doing better. 

You only get surgery once. 

You want to maximize its efficacy by doing it at the best time for YOU. The time in your life when you can take full advantage of its benefits. 

If you’re not ready, that’s okay. Seek a dietitian near home to work with regularly and/or a counselor to help shift your mindset and overcome barriers. 

The most challenging work you will do is before surgery.

So get started now!

Use this guide to improve your eating habits and relationship with food so you can feel comfortable and confident, maximizing the benefits from weight loss surgery. 

As you get closer to surgery, be sure to check out my blog post on the 3 Month Pre Bariatric Surgery Diet: 7 Dietitian Tips. This guides you through the additional habits you need to add just before surgery.

If you need guidance on meal planning for healthy balanced meals that include sufficient protein and help with weight loss check out my recipe booklet: 15 Macronutrient Balanced Recipes

For more tips, join my community in the Facebook Group: Weight Loss Support for Moms with (and without) Insulin Resistance.

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