Doctors on call — whether foundation year trainees doing their first on-calls or consultant physicians covering weekends — face a nutritional challenge with direct patient safety implications. Cognitive performance, decision-making quality, and procedural accuracy are all measurably affected by dietary quality and blood glucose stability. A doctor making a clinical decision in hour 14 of an on-call shift on an empty stomach or post-sugary-vending-machine-snack glucose crash is not performing at the same standard as one who has eaten well. Nutrition is a patient safety issue in medicine, not just a personal wellbeing concern.
The cognitive performance stakes in medicine
Research on decision-making under cognitive load consistently finds that blood glucose instability — the spike-and-crash that follows refined carbohydrate snacks — significantly impairs the executive function, working memory, and risk assessment that clinical decision-making requires. For doctors, this is not an abstract performance concern — it is directly relevant to the quality of clinical judgment during the hours immediately following a high-glycaemic meal or snack.
Practical nutrition for hospital on-calls
The pre-on-call meal should be substantial, protein-forward, and low-glycaemic — eaten 2-3 hours before starting, providing sustained energy without a mid-shift crash. Mid-on-call snacks should be protein-fat combinations (nuts, protein bars, hard-boiled eggs) rather than the vending machine carbohydrate options that hospital on-call rooms typically offer. Hydration is consistently underestimated — a 500ml water bottle refilled regularly through the shift prevents the dehydration-induced cognitive impairment that is indistinguishable from fatigue.
NHS hospital catering improvement
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Frequently asked questions
What foods are most effective for maintaining cognitive performance during a long on-call shift?
Foods that produce stable blood glucose without a rapid post-meal spike are most effective for sustained cognitive performance: legumes, whole grains, oily fish, eggs, and lean protein with non-starchy vegetables. These produce slower glucose absorption, supporting the executive function, working memory, and risk assessment that clinical decision-making requires over a long on-call period.
How much should a doctor eat during an on-call shift to maintain performance without feeling sluggish?
Smaller, more frequent meals spaced through the shift are more effective for sustained performance than one or two large meals. Large meals divert blood flow to the digestive system and produce a post-prandial fatigue effect that compounds the cognitive load of on-call work. A moderate pre-shift meal followed by small protein-fat snacks every 3-4 hours is a more effective pattern than skipping meals or eating heavily at one sitting.
Do energy drinks or high-sugar snacks from hospital vending machines impair clinical performance?
Yes. High-sugar snacks and energy drinks produce a rapid blood glucose rise followed by a crash, which impairs the executive function and working memory required for clinical decision-making in the 60-90 minutes after consumption. The performance impairment from a glucose crash is measurably similar to mild sleep deprivation in its effect on complex cognitive tasks — a meaningful patient safety risk during a long on-call shift.
Does skipping meals on a busy on-call shift affect clinical decision-making quality?
Yes. Prolonged fasting during on-call periods produces hypoglycaemia-adjacent blood glucose states that impair cognitive function, increase irritability, and reduce the quality of risk assessment — the core competency in clinical decision-making. Missing meals on on-call is not a time-saving strategy; the cognitive performance cost in the hours following a skipped meal exceeds the time saved by not eating.
What is the relationship between hydration and cognitive performance for doctors on long shifts?
Even mild dehydration — 1-2% of body weight — produces measurable impairments in attention, short-term memory, and psychomotor performance equivalent to a blood alcohol level of 0.05%. For a doctor on a 16-hour on-call shift in a warm hospital environment, maintaining hydration is a direct patient safety measure, not just a personal comfort consideration.