Bariatric surgery results in long term weight loss with resolution of comorbidities. The surgery typically results in excess weight loss of 60-90% over a period of 12-15 months. The weight loss is mostly from the excess subcutaneous fat but there is often loss of muscle and decreased bone density as well.
After bariatric surgery, a caloric deficit is created in the body which results in a catabolic state. The hormones responsible for lipolysis and gluconeogenesis are activated which result in fat as well as protein breakdown and conversion of these substrates into glucose. The fat breakdown is desirable but protein breakdown may result in muscle loss and weakness. In order to prevent this, patients are advised to consume a high protein diet to replenish any muscle loss as a result of catabolic hormones.
The normal requirement of protein for a healthy adult is 1 g/ kg of body weight to compensate for the wear and tear in daily activities. However, this demand is increased to 1.5-2 g/kg of body weight in patients who have undergone bariatric surgery to compensate for their rapid weight loss. This means that such patients may require 80-120 g of protein per day.
Such a high quantity of protein cannot be met just by diet alone and requires supplementation. Numerous protein supplements are available but generally whey protein fortified with essential vitamins is preferred as it is easily digestible and provides essential vitamins as well.
Protein supplements are stated within a week of undergoing surgery during the phase of liquid diet. The patients are instructed to begin with a small serving of 3-5 g with a small cup of water or milk 2-3 times a day. The portion size may be increased to 10-15 g per serving over the next few months depending upon the requirement of the body. Generally , those patients with higher initial BMI tend to have greater and more rapid weight loss and require more protein.
The protein consumption should also be prioritised in the diet as well. Foods having high protein content should be consumed first followed by carbs and fats. Proteins not only help prevent muscle loss but are also essential for regulating metabolism snd immunity as well. The proteins in diet provide satiety and limit the intake of carbohydrates which promote weight loss. Muscle tissue is a metabolically active tissue with a high basal energy consumption. Hence, having a greater muscle mass leads to higher BMR and promotes weight loss as well as avoids weight regain.
Thus, protein supplements should continue for long term in patients who have undergone bariatric surgery as they are required for maintaining the weight and overall health and well being.