Bariatric Diet: Phases, Meal Plan & What to Eat or Avoid

Following bariatric surgery, patients adhere to a liquid diet for about 3 weeks and then a soft diet for another 21 days. After this period, solid foods can be slowly introduced.

Reaching a normal diet after bariatric surgery can take up to 3 weeks. The time spent in each phase of a bariatric surgery depends on each person and their tolerance post-surgery, which is why it is important to be monitored by a registered dietitian.

This adaptation period after bariatric surgery is important as the stomach becomes very small. Initially, it can only tolerate 30 to 60 mL of liquid, which progresses to about 200 mL. Beecause of the reduced gastric capacity, the body is unable to fully absorb nutrients, leading to rapid weight loss. 

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Bariatric diet phases

The bariatric diet is divided into phases, in accordance with each person's tolerance: 

First phase: liquid diet

The liquid diet starts soon after surgery and lasts for 3 weeks. You can only consume liquid foods in very small quantities several times throughout the day. 

During this phase, you should consume plenty of protein and reduce your fat and carbohydrate intake. You should prioritize: 

  • Protein supplements and food, like skim powdered milk and protein shakes to mix with other foods 
  • Milk and other milk alternatives, like 1% or skim milk, soy milk or oat milk 
  • Vegetables and grains, consumed as thin broths, which can include all types of boiled vegetables (like pumpkin, carrot, sweet potato, squash or eggplant). You can consume small amounts of potato, corn meal or rice. 
  • Fruit juices that are very diluted, like papaya, peach, pear, and apple (avoid citrus fruits) 

In addition, you can also include other liquids during this phase of your bariatric diet, like teas, jello, and unsweetened icecream, It is also important to take your daily supplements as prescribed by your doctor or dietitian, like calcium and vitamin D. 

Food should be eaten slowly, and it may take up to 40 minutes to eat one serving of soup. You should avoid using straws to consume your liquids. 

In the first 7 days, your stomach capacity is restricted to very small volumes, about 30 to 50 mL. It gradually increases to 60 to 100 mL. As your tolernace improves, you can also upgrade the consistency and the volume of your food, to up to 150 to 200 mL.

Second phase: soft diet

The soft diet should be started about 21 days after bariatric surgery. During this phase, you can eat foods that are crushed or mash. Some examples include:

  • Protein, like eggs, tofu. and white meat (like turkey, chicken or fish), depending on your tolerance 
  • Dairy, like fat-free yogurt, kefir, cream cheese, cream pudding (with no sugar or fat) 
  • Vegetables and grains that are mashed and creamy soups that are low in fat, made with vegetables like pumpkin, squash, carrots, eggplant, broccoli, potatoes, sweet potatoes and porridge, made from corn, rice or oats
  • Fruit puree without the peel or seeds 

During this phase, you should aim to consume between 150 to 200 mL, spread out through 5 to 6 meals per day. You should avoid ingesting liquids together with your main meals. 

In some cases, some foods can cause more gas, like broccoli, cauliflower, brussel sprouts, cabbage and beans. You should avoid consuming these foods if you experience more gas. 

In addition to supplements, your doctor or dietitian may also prescribe liquid or chewable multivitamins or minerals. 

Third phase: solid food

About 30 to 45 days after bariatric surgery, you can start to eat solid foods. They must be well chewed and ingested in small portions, taken over 6 meals per day. In this phase, in may be helpful to use a dessert plate to ensure small quantities at each meal. 

Liquids should only be consumed between meals, and it is important to drink at least 2 L of water to prevent dehydration. 

After this phase, you can eat more fruits, vegetables, whole grains, milk and dairy, meat, fish, eggs, pasta, rice, potatoes, whole grains and seeds in small quantities, depending on your tolerance. 

Bariatric diet meal plan

The following are sample bariatric diet meal plans that you can follow after surgery: 

Meal Clear liquids Full liquids
Breakfast (08:00) 30 to 50 mL of strained papaya juice  60 to 100 mL of cream of rice (without milk) + 1 teaspoon of protein powder 
Morning snack (10:00) 30 to 50 mL of linden tea  60 to 100 mL of strained papaya juice + 1 teaspoon of protein powder 
Lunch (12:00) 30 to 50 mL of skim milk or milk alternative with 1 teaspoon of protein supplement  60 to 100 mL of vegetable soup, titrated (pumpkin, squash and carrot) 
Snack 1 (14:00) 30 to 50 mL of strained pear juice  150 to 200 mL of peach juice + 1 teaspoon of protein powder 
Snack 2 (16:00) 30 to 50 mL of liquid gelatin with no sugar  150 to 200 mL of liquid gelatin with no sugar + 1 teaspoon of protein powder 
Dinner (18:00) 30 to 50 mL of skim milk or milk aternative with 1 teaspoon of protein supplement  150 to 200 mL of vegetable soup (celary, pumpkin, parsnip and corn)
Evening snack (20:00) 30 to 50 mL of carrot and pumpkin broth, strained 150 to 200 mL of apple juice + 1 teaspoon of protein powder 

It is important to take small, slow sips to allow time for the stomach to digest the food. It is important to start with 2 tablespoons (39 ml) every 5 minutes and to increase the speed and volume gradually. 

Eating or drinking your food quickly can stretch your stomach and/or open a pocket between the stomach and intestines. With time, the stretching can lead to permanent increase in stomach size, leading to weight gain.  

Meals Soft diet Semi-solid diet
Breakfast 150 to 200 mL of oatmeal with skim milk + 1 teaspoon of protein powder  150 mL of skim milk with 1 slice of toast and 1 slice of white cheese 
Morning snack 150 to 200 mL of papaya juice + 1 teaspoon of protein powder 1 small banana
Lunch 150 to 200 mL of vegetable soup, titrated with chicken + 1 tablespoon of pumpkin puree without butter  1 tablespoon of titrated carrots, 2 tablespoons of minced meat and 1 tablespoon of rice 
Snack 150 to 200 g of boiled and pureed apple  200 mL of chamomile tea + 1 slice of toast
Dinner 150 to 200 mL of vegetable soup, titrated with fish + 2 tablespoons of mashed potatoes without butter   50 g of pulled chicken + 2 tablespoons of mashed potatoes 
Evening snack 150 to 200 mL of pear juice + 1 teaspoon of protein powder  200 mL of chamomile tea and 1 cracker 

During these phases, you are advised to rink between 100 to 150 mL of water or tea between meals. This will help to gradually increase your tolerance up to 2 L of water per day. 

What to avoiding eating

In the first 3 months after bariatric surgery, you should avoid eating foods like: 

  • Coffee, yerba mate, green tea and black tea
  • Peppers, processed condiments (like knorr), mustard, ketchup and worcestershire sauce 
  • Processed juices, soda, chocolate drinks and sparkling water 
  • Citrus 
  • Raw vegetables and fruit with the peel
  • Chocolate, gummy candy, hard candy and gum
  • Fried food
  • Alcohol 

Also, food like chocolate mouse, condensed milk and ice cream should also be avoided. These are high in calories and can lead to weight gain, even if consumed in small quantities. 

General recommendations

Some general recommendations for a bariatric diet include: 

  • Eat in small quantities
  • Adhere to a low-calorie diet
  • Avoid food that is high in fat
  • Eat slowly and chew thoroughly, be sure to take small sips of liquids 
  • Avoid using straws
  • Avoid consuming gassy drinks, as they can lead to gas and discomfort 
  • Avoid sugar and sugary drinks 

After bariatric surgery, it is important to change your dietary habits and to maintain a healthy, balanced diet. This will promote eight loss and prevent nutritional deficiencies and gastric symptoms.