Nutrition Support for the Obese Surgical Patient

Jay M. Mirtallo, MS, RPh


January 14, 2008

In This Article


Obesity in the postoperative patient presents significant challenges for the clinician providing nutrition support. These patients are at higher risk of developing complications from surgery that requires nutrition support. Also, the medical conditions and physiologic effects of obesity interfere with the success of nutrition and potentially could exacerbate its complications.

When indicated, the caloric and protein dose provided to the obese surgical patient should be chosen carefully. These doses may depend on the severity of obesity and the goal of nutrition support. For the morbidly obese surgical patient, hypocaloric nutrition support is a reasonable approach. The caloric dose that has been used successfully is 50% of the measured energy expenditure. If energy expenditure cannot be measured, another approach is to use a predetermined formula that provides 2 g protein/kg IBW and 14 cal/kg actual body weight.

For lower classes of obesity, the approach will depend on the goal. If the goal is weight loss with preservation of protein reserves, hypocaloric nutrition support may be used. If maintenance of weight is desired until after recovery from the surgical procedure, then provision of adequate calories is necessary. The caloric dose could be estimated as 25 kcal/kg adjusted body weight, using a factor of 50% to adjust the body weight. Protein doses for hypocaloric nutrition support are 2 g/kg IBW; lower doses may be used for regimens that provide calories to meet estimated needs.

These approaches have not been evaluated in patients with renal or liver disease, so the use of hypocaloric nutrition support in patients with these conditions is not advocated at present.

Many factors influence the accuracy of methods used to determine energy and protein needs in the obese surgical patient, so any approach needs to be monitored closely for adverse effects, especially if it results in an excess caloric dose.


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