Nutrition support in the obese, diabetic patient: the role of hypocaloric feeding

It has previously been thought that meeting estimated caloric needs with nutrition support improves outcomes in critically ill, obese patients with diabetes. Recent data suggests that intentionally failing to match caloric expenditure may actually result in better outcomes than eucaloric feeding. This review will evaluate recent studies exploring the relationship between caloric intake and outcomes in obese patients with underlying insulin resistance or diabetes.

Obese patients who receive 33-70% of their estimated caloric needs during critical illness have better clinical outcomes than patients fed eucalorically. The reasons for this are not clear, however, they do not appear to be due to improved glycemic control. It is possible that caloric restriction acts by improving insulin sensitivity in protein and glucose metabolism, reducing the risk of infection without causing severe hypoglycemia. Patients who are unable to achieve goal-feeding rates have poorer clinical outcomes but this is most likely due to severity of illness rather than caloric intake itself.

It is better to err on the side of hypocaloric nutrition support in obese, diabetic patients rather than overfeeding. Hypocaloric feeding may result in improved outcomes, however, the optimal duration of hypocaloric nutrition support is not known.