Diet Restrictions After Bariatric Surgery

Reviewed by: HU Medical Review Board | Last reviewed: August 2023

Bariatric surgery is for people with severe obesity who want to lose weight. It is a life-changing procedure that requires consistent lifestyle changes after surgery. Adopting a healthy diet and portion control both can reduce complications and improve outcomes. Making these changes is crucial for long-term success.1-3

Transitioning to a new diet

After bariatric surgery, your digestive system undergoes some pretty big changes. This requires a gradual transition to a new diet plan.1,2

Generally, you progress through several post-surgery diet phases. Right after surgery, you likely will not be allowed to eat for 1 to 2 days. This gives your body time to heal. Then, you move on to a clear liquid diet. Over the course of several weeks, you will advance to pureed foods, soft foods – like cottage cheese, yogurt, and soup – and eventually solid foods.1,2

Each phase allows the gastrointestinal (GI) tract to heal and adapt to the changes brought about by the surgery. It may take several months to get back to a normal diet. You will have plenty of post-surgery checkups with your bariatric care team. They will guide you through each phase and tell you how long each phase lasts.1,3

Long-term dietary guidelines

Once you reach the solid foods phase, be intentional about the quality and quantity of the foods you eat. In general, people who are eating a normal diet again after bariatric surgery should aim for about 900 to 1,000 calories each day. But each person is different. Talk with your healthcare provider about the total number of calories is right for you.4,5

Sticking to the following diet guidelines can help you maintain weight loss and promote overall well-being.4

Increase your protein

Protein is an essential macronutrient that helps with tissue repair and feeling full. It also helps preserve lean muscle mass as you lose weight. Experts recommend getting 60 to 100 grams of protein per day.4

Try including some of the following lean sources of protein in each meal:4,5

  • Eggs
  • Poultry
  • Fish
  • Legumes (beans, peas, and lentils)
  • Tofu

Limit carbs

Limiting refined carbs and sugars is essential for sustained weight loss. Focus on complex carbs like whole grains, fruits, and vegetables. These provide fiber and other vital nutrients.4

Hydrate

Stay well hydrated by drinking water throughout the day. Aim for at least 64 ounces daily, unless otherwise advised by your doctor. Try to drink 1 full glass of water between each meal.4,5

Supplement with vitamins and minerals

Bariatric surgery can affect the body's ability to absorb specific vitamins and minerals. Following surgery, you will need to take vitamin and mineral supplements to reduce your risk of nutrient deficiency. The following may be recommended:4,5

  • Daily multivitamin
  • Calcium
  • Iron
  • Vitamin B12
  • Vitamin D

Avoid carbonated drinks

Carbonated drinks can lead to bloating and discomfort due to the changed digestive system. It is best to avoid them.5

Limit alcohol

Be careful how much alcohol you consume. For people who have had weight loss surgery, alcohol is absorbed much faster. This makes alcohol’s effects stronger than before.5

What to know about portion sizes

Portion control is key in maintaining weight loss after bariatric surgery. The stomach's capacity is reduced, meaning it cannot hold as much as before. Be mindful of how much food and liquid you consume.5

Here are some general guidelines to follow.

Eat small, frequent meals

Aim for 5 to 6 small meals throughout the day, rather than 3 large ones. This helps prevent overeating and keeps your metabolism active.5

Chew thoroughly

Take the time to chew food thoroughly and eat slowly. This aids in digestion and allows you recognize when you are actually full.5

Mindful eating

Pay attention to hunger and fullness cues. Eat until you feel satisfied but not overly full. To eat mindfully, avoid distractions like TV and electronic devices while eating.5

Measure your portions

Use measuring cups or a food scale to portion out meals and snacks. This can help you understand what portion sizes are appropriate for you.

Avoid high-calorie foods

Steer clear of calorie-dense foods, such as fried and processed foods, sweet snacks, and sugary beverages. Instead, opt for nutrient-dense options that promote fullness without a lot of extra calories.5

A lifelong commitment

Bariatric surgery offers those with obesity a valuable way to achieve weight loss. But it requires a lifelong commitment to a healthy diet and portion control.

Always talk with your doctor about any concerns or questions you may have. Work with your doctor and/or a registered dietitian to customize a post-surgery diet that meets your specific needs.

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