Bariatric surgery is a life changing experience to say the least especially in terms of the diet which has to be followed post surgery. Patients usually go through 4 phases of strictly followed diet in the initial 6-8 weeks following their surgical procedure but after that, the instructions for their diet are less clear. The patients who are able to maintain a proper diet thereafter have lesser chances of nutritional deficiencies and any adverse consequences related to their bariatric surgery.
After any bariatric surgery, once solid diet is resumed after 6-8 weeks, the food intake has to be divided into 4-6 small portions which are to be consumed every 2-4 hours. Initially soft foods are preferred but once normal diet is resumed, the food has to be taken slowly and chewed thoroughly. It has to be remembered that the new stomach cannot accommodate food quickly as it has lost its property of elasticity and there a tendency to regurgitate if it is over distended. Patients must separate liquids from solids to prevent bloating. Using straws should be avoided as well as gulping liquids as it leads to aerophagy and can precipitate vomiting.
Patients should avoid aerated drinks, black tea and coffee and concentrated alcohol. Aerated drinks release gas in the stomach and can stretch the new stomach whereas the others can lead to gastritis and pain especially in the initial few months of surgery. High calorie liquids, white sugar and processed foods like pastries, ice creams and desserts are a no-no as they can bypass the restriction offered by the bariatric surgery and can hamper weight loss seriously.
Protein is one of the most critical aspects of diet following bariatric surgery as it is one of the most often which is deficient. An average adult human requires 1 gram/kg of protein per day in order to maintain a healthy metabolism and muscle mass. Post bariatric surgery, this requirement can increase to 1.5-2gm/kg of body weight depending upon the type of procedure performed. Restrictive procedures like gastric banding and sleeve gastrectomy usually donot increase the requirement for protein but malabsorptive and combine procedures like the Mini gastric bypass and Roux en Y Gastric bypass mandate an increase in protein intake.
Protein can be classified into vegetable and animal protein and can be in the form of liquid or solid. In the initial few weeks of surgery, the main source of protein comes in the form of milk. This can be supplemented by various protein powders containing whey protein. This helps in enzyme synthesis and maintenance of muscle mass in the phase of rapid weight loss and prevents wasting. Other liquid sources can be soy or almond milk, dal as well as various soups. These should be consumed at intervals of 3-4 hours throughout the day to have efficient absorption and supply to the body.
Solid protein is usually started 8 weeks following bariatric surgery. It includes vegetarian sources like legumes, nuts, green leafy vegetables, tofu and cottage cheese. Amongst the non vegetarian sources, egg whites and lean meats like fish and chicken are the preferred ones. These offer a high quality protein without the presence of excess fat. Protein not only is the most essential component of diet in the first year following surgery, it also helps to maintain satiety and prevents the intake of excess calories throughout the day. Each small meal should contain 12-15 grams of protein which should be consumed firstly before going on to carbohydrates or staples. 4-5 such small meals would ensure daily intake of 60-80 grams of protein for the person who has undergone bariatric surgery.
Besides protein, fibre has an essential role to play. It also provides satiety, regulates bowel motility and prevents constipation, a common complaint of patient after bariatric surgery. Fibre can be found in the peels of various fruits and vegetables, unpolished rice and unrefined flour.
Vitamins and minerals can again be found in most unprocessed foods especially in raw vegetables and fruits. Yellow fruits and vegetables like mangoes, papaya, carrots, etc are rich in the fat soluble vitamins (A,D,E and K) which are essential for good skin and hair while the green vegetables contain more of iron, zinc, calcium which are responsible for blood formation and healthy bones. Citrus fruits like orange and lemon contain more vitamin C which helps immunity. Milk is the most complete food in this regard as it contains all nutrients except for vitamin C and iron.