Rebuilding Your Diet After Weight Loss Surgery

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Weight loss surgery (bariatric surgery) will help you lose weight and improve your health with additional lifestyle changes. Perhaps one of the biggest changes after weight loss surgery is going to be your diet. It can be very different from your pre-surgery diet. This may seem overwhelming at first, but time and practice will make your new way of eating a habit. 

Prepare now for your life after bariatric surgery. Before you know it, your post-surgery diet will be part of your everyday routine. Find out how your diet will change and the steps to healthy eating after weight loss surgery.

Food Consistency 

You will eat a liquid diet for 2 to 3 weeks after weight loss surgery.  Your liquid nutrition will be protein-rich with the slow addition of carbohydrates. Your doctor or dietitian will tell you when it’s time to transition to a soft-food diet. Soft foods include items like yogurt, eggs, and soft-cooked vegetables. This soft-food diet usually lasts from 6 to 8 weeks. 

You will gradually transition from soft foods to solid foods. Depending on the specific type of surgical procedure and individual recovery, it can take 6 to 9 months after weight loss surgery to fully move from a liquid diet to a regular diet.

Portion Size

You will only be able to consume small portions after weight loss surgery because stomach capacity was reduced by surgery. This usually means two ounces or about one-quarter cup at a time. Smaller portions mean that the intervals between meals are short at first. You may find that you need to take a bite or mouthful and wait several minutes before taking another. If you go too fast or eat too much, you may have pain, nausea, or spit up your food. 

Your goal should be to consume small-portioned meals over 20 to 30 minutes. Don’t worry! Even with these tiny meals you won’t feel hungry.


Your daily calorie goal after weight loss surgery may be shocking. Right after surgery, you’ll only be consuming about 300 to 500 calories per day. This is in contrast to a typical intake of 1,785 to 2,640 calories for women and men older than age 19, according to national survey data at 

Long-term, your daily caloric intake should never exceed 1000 calories. These limits are vital for achieving and maintaining your weight loss goals.


One of your main dietary goals is consuming protein. Protein will help your body heal and maintain muscle during weight loss. Your lifelong focus should be high-protein, low-fat, low-calorie foods. Eating high-fat foods may make you feel nauseous and will slow your weight loss. Eat your protein foods first during a meal so you don’t get full before you get your protein.

On your liquid diet, you can get protein from nutritionally complete protein drinks and skim milk. As you transition to soft foods, good protein sources include eggs, cottage cheese, yogurt, refried beans, and soft fish. Remember to choose low-fat versions of your protein foods.

Your portions will always need to be small, so choose proteins wisely. Choose ground or soft-cooked lean meats, low-fat dairy, soy, and beans or legumes. Avoid peanut butter, hard cheeses, cream cheese, bacon, sausage, cured meats, and other high-fat protein sources. 


Starchy foods, such as breads, rice and pasta can be a problem for people after weight loss surgery. Not only is tolerance an issue, but these foods may also trigger former eating habits because some of these foods can make you hungrier. Instead of getting carbohydrates from these sources, you need to focus on fruits and vegetables. But avoid skins, dried fruits, and raw vegetables. Eat fruits without the skins and cook vegetables to soften them, making them easier to tolerate.

Vitamins and Minerals

It can be a challenge to get enough vitamins and minerals because your meals will always be small. In addition, your digestive tract can’t absorb nutrients the way it did in the past. As a result, you will need to take a vitamin and mineral supplement. Talk to your doctor or dietitian about the specific amounts and types of supplements you need.


You will need 6 to 8 cups of fluid each day to avoid dehydration after weight loss surgery. The key is drinking small amounts of fluids frequently. But you need to separate your fluids from your meals. This may be different from what you are used to doing. Consuming liquids with your food can cause the food to pass too quickly through your stomach. This can cause pain and make you feel hungry again sooner.

Avoid drinking fluids 30 minutes before your meal. Filling up on liquid will limit the amount of food you can consume. You should also avoid using straws. Straws can cause you to swallow air, which will take up valuable stomach space. Instead, take small sips from a container. At first, you’ll tolerate room-temperature liquids best.

The types of liquids you can drink will be a lifelong change. You should always avoid carbonated beverages, including any type of soda or pop. Carbonation fills your stomach with gas, causing discomfort. More importantly, carbonation can stretch your stomach pouch or its outlet. This leads to a larger pouch that can hold more food, undermining your weight loss and long-term health goals.

Choose low-calorie, caffeine-free beverages. Your best choice is water. You can add flavor with lemons or low-calorie flavor packets. You can also opt for herbal teas or artificially sweetened drinks.

Eating Behaviors

How you eat is going to be as important as what you eat. To ease digestion, you’ll need to take small bites and chew thoroughly. It’s also vital that you learn to eat slowly and stop eating when you feel satisfied. Budget the time necessary for you to enjoy eating at a much slower pace. Continuing to eat after you are full can cause severe pain and vomiting. Making these new eating behaviors a habit will help ensure your weight loss success after bariatric surgery.

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Medical Reviewer: William C. Lloyd III, MD, FACS
Last Review Date: 2020 Jul 29
THIS TOOL DOES NOT PROVIDE MEDICAL ADVICE. It is intended for informational purposes only. It is not a substitute for professional medical advice, diagnosis or treatment. Never ignore professional medical advice in seeking treatment because of something you have read on the site. If you think you may have a medical emergency, immediately call your doctor or dial 911.
  1. Dietary Guidelines After Bariatric Surgery. University of California San Francisco Medical Center.
  2. Learn More. University of Michigan Health System Adult Bariatric Surgery Program.
  3. The Post-surgery Diet for Bariatric Patients: What to Expect. Obesity Action Coalition.