(MAT Jan 2015)
Over-fed does not mean well nourished
There is a common perception that people with obesity are in a state of ‘over nutrition’ but often the opposite is true. People who present for bariatric surgery may be in a state of malnutrition. Poor quality diets, fad diets, lifestyle choices and side effects from some medications negatively influence the preoperative micronutrient status of the morbidly obese. Overweight and obese individuals are at risk for deficiencies in several micronutrients including iron, vitamins D, B12, E and C.
Obesity management does not stop with surgical intervention. Both obesity and its management are complex. Therefore the National Institute of Health, American Society for Metabolic and Bariatric Surgery and NHMRC recommend long-term nutrition and medical follow-up and advocate a team approach that includes a bariatric dietitian.
The dietitian’s role in bariatric surgery management
The dietitian’s role is a vital component of the bariatric surgery process, starting prior to admission and continuing life-long after discharge. The dietitian assesses the nutritional status of the patients to identify and treat any nutritional deficiencies, designs medical nutrition therapy interventions, and provides extensive education, counselling and support throughout the weight loss journey to help prevent complications and maintain optimal weight loss.
Dietitians in the acute care setting liaise with the food service/catering department and other stakeholders to develop, as well as ensure provision of an appropriate therapeutic bariatric diet. During complications and in acute illness, nutrition support to preserve lean body mass and enhance recovery of patients takes priority over weight loss.
Because the risk for micronutrient deficiencies persists or may worsen over months and years after bariatric surgery, ongoing comprehensive nutrition screening is required by the bariatric dietitian to ensure optimal nutritional status.
Bariatric surgery carries both short and long term nutritional risk
Maintaining adequate nutrition is a challenge. Every bariatric surgery leads to very reduced total kilojoule (kilocalorie) intake, especially in the first six postoperative months, typically ranging from 2900-3800 kJ (700-900 kcal) per day following RYGB. This contributes to the decreased intake of all macronutrients especially protein as patients may have difficulty consuming their recommended protein requirements.
The emphasis of postoperative nutritional care is to: