Bariatric Surgery FAQ

Keto Diet Gastric Bypass

Keto Diet Gastric Bypass - Bariatric Fusion

You must have heard about the Keto/Ketogenic diet. It is defined as a high fat, low carb diet.

Is a keto diet safe post gastric bypass? The answer is going to vary based on the individual. This diet is very complex and requires food restriction that can be very difficult for long-term use. If you are not guided by a medical professional, the high amounts of fat required in the diet can lead to unwanted side effects post-op. There can also be health concerns if unhealthy fats are chosen over healthy fat options.

Due to the high fat intake, this diet can be lacking in protein and fiber which is essential to the digestive processes and muscle maintenance needed after bariatric surgery. This is where a modified keto diet might come into play.

Gastric Bypass surgery is a major operation. It alters the normal physiology of the digestive tract. For long-term success, you will need a bariatric diet that is maintainable for life in order to see the most benefits from bariatric surgery.

In this article, we let you in on everything you need to know about the keto diet and how it could affect your post gastric bypass results.

keto diet gastric bypass

Origin of The Keto Diet

The Keto diet was actually created to treat medical conditions, such as epilepsy in children. Over time, this diet has become a popular way of eating for weight loss.

The normal source of energy for the body is from the breakdown of carbohydrates in order to use glucose as your fuel source. While carbohydrates are broken down, fat is typically stored.

The process of ketosis is to switch the body from utilizing carbohydrates as energy and instead, burn stored fat as energy. This results in ketone production as a primary source of fuel.

Is The Keto Diet Ideal Post Gastric Bypass?

As stated above, the answer to this question is going to vary based on the individual. Diet history and medical conditions have to be taken into account.

Conventionally, the keto diet consists of a ratio of 70% of fats, 25% of protein, and 5% of carbohydrates. This ratio does not appropriately support your body’s needs post gastric bypass. If the keto diet is going to be followed after surgery, you will have to consult with your dietitian on a modified keto diet, including a higher percentage of protein.

Typically, a bariatric diet consists of high protein (protein-centered), low carb, low-fat diet. This is what eating after gastric bypass surgery recipes usually look like.

As already emphasized, recipes for after gastric bypass surgery should prioritize protein, whole grains, healthy fats, fruits, vegetables, and your bariatric vitamin supplements for life.

Ketogenic diet-friendly foods, which are quite different from the gastric bypass foods list, include meat, fish, and healthy fats. Healthy fats include nuts and seeds, which may not be well tolerated initially following surgery. Other healthy fat options include salmon, extra virgin olive oil, and avocados.

Keto is mostly an animal-centered diet that restricts the intake of whole grains, fruits, and vegetables that can be essential sources of fiber. If going forward with a modified keto diet after gastric bypass, you will have to discuss with your dietitian appropriate sources of fiber to include.

If you are looking into the keto diet because you are having trouble with weight regain after surgery, think back to the basics. A bariatric cookbook is a great buy and can help you with portion control and offer creative meals. It will provide you with excellent food choices that are low in calories. Another option may be bariatric dinnerware that can further aid in maintaining your portion control.

Despite short-term results, the keto diet has not been studied in bariatric patients for long-term use. If you cannot maintain the diet long-term, research has shown that weight regain is likely.

For some, a modified keto diet may be suitable with the proper education, medical supervision, and long-term maintenance.

Keto Diet and Bariatric Surgery

Keto Diet and Bariatric Surgery

Restrictive diets can be beneficial for some when monitored by healthcare professionals, however, it may be best to keep things simple post-op since life after bariatric surgery is a huge adjustment.

Your body’s major change is a huge deal. You will be very vulnerable post-op. Not only will you have to adjust to lifestyle and diet change, you will be required to take bariatric vitamins for life to prevent common deficiencies due to surgery itself.

As explained, a bariatric patient would need to adjust to a protein-rich, low carb, and low-fat diet to accommodate for the new stomach and digestion. A protein-centered diet is essential for healing, muscle building and maintenance for a healthy metabolism. A stable diet will also aid your immunity.

A high-protein diet can include bariatric protein soup, which is a great savory option after surgery. Protein shakes after bariatric surgery are highly recommended to supplement the diet and meet daily protein goals.

A well designed after gastric bypass surgery diet plan will highlight high-protein meals tailored to the food phase you are in, for example, full liquids or soft foods.

Even if you are a candidate for the keto diet, beware that you’ll need to make a lot of adjustments to the conventional keto diet. Ideally, you shouldn’t be consuming high fats because they may not be well tolerated after surgery, causing possible dumping syndrome and steatorrhea.

More importantly, any modification to the keto diet should conform to the 1000 calorie bariatric diet plan that should be provided by your dietitian.

Additional Downside to The Keto Diet

Sustainability is a huge factor to this diet. It is highly restrictive and may not be realistic as a long-term solution.

Being on the keto diet leads to changes in your metabolic reactions. This is another reason why it is recommended to consult with a Registered Dietitian for dietary advice. The metabolic changes can cause an imbalance in thyroid hormones and can greatly affect those with prior thyroid issues.

On the keto diet, it is possible for bariatric patients to experience something called steatorrhea (fatty stools) due to the excessive dietary intake of fat. In turn, this can cause nutrient malabsorption and complications post-op. A high fat diet can also exacerbate dumping syndrome.

Another common side effect is described as the "Keto-Flu." This includes symptoms about 7 days after starting the diet. Many experience brain fog, headaches, fatigue, irritability, nausea, and constipation. This is due to the metabolic changes your body has to go through in order to breakdown fats for energy.

Keto is not suitable for those with liver, pancreas, thyroid and gallbladder conditions.


  • Low in carbs
  • Promotes short-term weight loss
  • Researched to treat seizure disorders in children
  • May aid in blood glucose maintenance
  • Maintains satiety
  • May support your energy and focus

However, there is insufficient research to support the benefits of a keto diet for long-term use post gastric bypass.

Keto Diet and Bariatric Surgery

Keto Diet Gastric Bypass (FAQs)

Can I Have Caffeine After Gastric Bypass?

Why no caffeine after gastric bypass? Caffeine should be avoided up to a month after bariatric surgery.

Caffeine can increase the risk of dehydration, stomach irritation, and exacerbate acid reflux.

Can I Have Alcohol After Bariatric Surgery?

Alcohol after gastric bypass is also not recommended. Alcohol is typically high in calories and sugar. It provides "empty" calories and can promote weight gain. If you are cleared to drink alcohol, do so in moderation considering your toleration will be altered after surgery.

What Does Your Diet Look Like Before Gastric Sleeve Surgery?

What to eat before gastric sleeve surgery? Initially, you will transition from a regular diet, to a full liquid diet, and then to a clear liquid diet before gastric sleeve.

A full liquid diet can be intimidating, but there are Gastric sleeve protein shake recipes available to assist you in this phase. This is typically called the liver reduction diet.

What Does Your Diet Look Like After Bariatric Surgery?

The Bariatric food pyramid is an awesome, easy-to-read guide. It offers guidance on what foods to eat in order to maintain a healthy weight loss journey. This will emphasize protein intake.

High-protein foods for gastric sleeve patients and gastric bypass patients are going to be essential after bariatric surgery. There are meal plans for gastric sleeve patients available through your dietitian to help you adjust to your new lifestyle after surgery.

The gastric sleeve diet week 3 starts to allow transition to soft and pureed foods. Before you know it, you will be eating 6 months after gastric bypass and gastric sleeve. At this point, you should be maintaining a regular, low-calorie, high protein diet.

Look into purchasing a bariatric cookbook. This is a great tool to offer creativity in your meal selection while following your bariatric diet. Some recipes may include bariatric pancakes or bariatric cheeseburger pie.

Can You Eat Out After Bariatric Surgery?

There are bariatric restaurants available when deciding to dine out post-gastric bypass. The best restaurants for bariatric patients are equipped with healthy alternatives, proper cooking methods, and lean protein entrees.

When eating out after gastric bypass, it is best to look for a smaller dinner option or side. Stay open to sharing a meal and ordering alternative sides.


Air on the side of caution when it comes to fad diets. If you are interested in a specific diet, consult with your bariatric healthcare team.

Modifications will likely have to be made to a keto diet if you are a bariatric patient. There will have to be adjustments made to the protein and fat ratio in order to support your new bariatric life.

At this time, there is insufficient research to support the benefits of a keto diet for long-term use post gastric bypass. The Keto diet may not be suitable for everyone.

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**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 physician or another qualified health provider with any questions in regards to a medical condition.

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