Editing Human nutrition (section)

=== Clinical nutrition ===
{{Main|Clinical nutrition}}
On admission to [[intensive care unit]], energy and protein requirements are calculated to determine the targets of nutritional therapy. Enteral nutrition (administering nutrition using a [[feeding tube]]) is started within 24 to 48 hours of admission with feeding targets increased every week. The risk of aspiration (inhalation of fluid or food particles while drinking or eating) can be reduced by elevating the head, using [[prokinetic agent]], and using a [[chlorhexidine]] mouthwash. Although the presence of bowel sounds and the amount of gastric residual volume aspirated after feeding can be used to monitor the functionality of the gastrointestinal tract before feeding is started; starting nutritional therapy at this stage regardless of the functional status is feasible and safe within 36 to 48 hours of admission. [[Parenteral nutrition]] (administering of nutrition [[intravenous]]ly) should be started when enteral nutrition is not possible or sufficient or in high-risk subjects.<ref>{{Cite journal | last1=McClave | first1=Stephen A. | last2=Taylor | first2=Beth E. | last3=Martindale | first3=Robert G. | last4=Warren | first4=Malissa M. | last5=Johnson | first5=Debbie R. | last6=Braunschweig | first6=Carol | last7=McCarthy | first7=Mary S. | last8=Davanos | first8=Evangelia | last9=Rice | first9=Todd W. |last10=Cresci |first10=Gail A. | last11=Gervasio | first11=Jane M. | last12=Sacks | first12=Gordon S. | last13=Roberts | first13=Pamela R. | last14=Compher | first14=Charlene | last15=the Society of Critical Care Medicine | date=February 2016 | title=Guidelines for the Provision and Assessment of Nutrition Support Therapy in the Adult Critically Ill Patient: Society of Critical Care Medicine (SCCM) and American Society for Parenteral and Enteral Nutrition (A.S.P.E.N.) | journal=Journal of Parenteral and Enteral Nutrition | language=en | volume=40 | issue=2 | pages=159–211 | doi=10.1177/0148607115621863 | pmid=26773077 | s2cid=3772578 | issn=0148-6071 | doi-access=free}}</ref>

Before undergoing surgery, a subject should avoid long periods of fasting. Oral feeding should be established as soon as possible after surgery. Other aspects of nutrition such as control of glucose, reduction in risk factors that causes stress-related [[catabolism]] or impairment of gastrointestinal functions, and encourage early physical activity to encourage protein synthesis and muscle functions.<ref>{{Cite journal | last1=Weimann | first1=Arved | last2=Braga | first2=Marco | last3=Carli | first3=Franco | last4=Higashiguchi | first4=Takashi | last5=Hübner | first5=Martin | last6=Klek | first6=Stanislaw | last7=Laviano | first7=Alessandro | last8=Ljungqvist | first8=Olle | last9=Lobo | first9=Dileep N. |last10=Martindale |first10=Robert | last11=Waitzberg | first11=Dan L. | last12=Bischoff | first12=Stephan C. | last13=Singer | first13=Pierre | date=June 2017 | title=ESPEN guideline: Clinical nutrition in surgery | journal=Clinical Nutrition | language=en | volume=36 | issue=3 | pages=623–650 | doi=10.1016/j.clnu.2017.02.013 | pmid=28385477 | s2cid=4235396 | doi-access=free}}</ref>