[ Vol. 12 No. 1 ] (January - April 2011 )
Overnight fasting is obsolete

Olle Ljungqvist
Karolinska Institutet, Sweden


One of the most well known traditions in surgical practice is the overnight fasting routine. It was first proposed after the first anesthesia death reported in the medical literature in 1848. It later became routine practice all over the world, but really without any scientific backing behind this practice. Rather, it was described in text books and as such became accepted as best practice.

It was not until the mid 1980’s that this dogma was challenged first from the pediatric anesthesia and later in adult practice as well. The basis for the challenge was to reduce the discomfort of thirst, but also to reduce headaches from caffeine withdrawal in some individuals. Repeated studies have shown that indeed overnight fasting is not the best way to prepare for elective surgical procedures. It is no guarantee for an empty stomach, which is the entire idea behind the concept. In fact, taking clear fluids often results in less fluids in the stomach than a fasted state. Allowing patients to drink abolished the thirst and improved well being before surgery. Based on these studies, many anesthesia societies around the Western world changed their fasting guidelines to recommend intake of clear fluids up until 2 hours before anesthesia. This is now the standard recommendation in all revised guidelines since about 15 years. Interestingly enough many countries still retain their old practices despite the overwhelming literature showing this to be obsolete.

In more recent years the fasting concept was challenged from another angle- the metabolic side of overnight fasting. We and others showed that instead of surgery in the overnight fasted state, a carbohydrate load - intravenously or preferably orally given 2-3 hours before the onset of surgery to change into a fed state, has many beneficial effects. These include, improved well being before surgery, less post-operative nausea and vomiting after surgery, improved metabolic state with less insulin resistance and less losses of body protein, lean body mass and muscle strength, and some smaller reports indicate shorter length of stay as an indicator of faster recovery. In addition, cardiac performance has been shown to be improved with this preparation.



Ljungqvist, O. and E. Soreide (2003). “Preoperative fasting.” Br J Surg 90(4): 400-6.

Soreide, E., L. I. Eriksson, et al. (2005). “Pre-operative fasting guidelines: an update. “Acta AnaesthesiolScand 49(8): 1041-7.


PENSA 2009

“Energizing Nutrition Support Practice for Life”
June 5-7 2009, Shangri-La Hotel, Kuala Lumpur, Malaysia 
Page: 51