We’re not very productive. Stagnant productivity is the reason wages have flatlined since 2008, leaving our pay packets £14,000 lighter than if they’d kept growing. British economists and policymakers worry about this a lot.

We are always on alert for signs of low productivity. For me, warning signs start flashing immediately after lunch. My mind slows, creativity dims and the inbox fills up. I thought this was a personal weakness. Or maybe just my soul dying slowly after another trip to Pret.

But new research reassures me that “postprandial somnolence” (the food coma) is real. A study in India investigated how the test scores of 4,600 students were swayed by their satiation. A lot is the answer. Those who’d eaten within an hour of their exam scored 17% lower in some subjects. The more complex the task, the more pronounced the decline in cognitive performance: reading comprehension declined by only 4% for individual words, but a whopping 18% for paragraphs.

This is problematic because, well, we do need to eat. Being “hangry” and needing a break brings its own troubles. Nobel prize-winning psychologist Daniel Kahneman, who died last month, helped popularise a study he’d edited, showing that judges were not neutral decision-making machines of legal theory. The probability of them granting parole dropped towards zero just before lunch, before jumping back up (to about 65%) immediately after.

Kahneman concluded that hungry judges paid less attention to detail and stuck with the “safe” option of denying parole. So being hungry isn’t great for productivity, either. What to make of this? Rather than training AI to take our jobs, why not get it to do something useful: cover the lunch shift.

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Torsten Bell is chief executive of the Resolution Foundation and author of the forthcoming book Great Britain? How We Get Our Future Back