The afternoon dip isn't the sandwich

The early-afternoon slump, when you get one, is mostly your body clock, not your lunch. It shows up even when people skip lunch. Evidence: decent That comes from a review of the research, not one big trial.

The sugar rush is a myth. A review of 31 studies and 1,259 people found carbohydrates, sugar included, didn't lift mood at any point. Evidence: solid In the first hour, people felt more tired and less alert than after a placebo. Evidence: decent So the biscuit doesn't fix the dip. For an hour it may make it worse.

That's in healthy people. With diabetes it's a different question, and your doctor's advice comes first.

What to do with the dip instead: hard work at your best hour, easy work in the slump.