Chocolate has long been held to be a mood-lifter.

It boosts levels of serotonin, the brain’s antidepressant, as well as endorphins, the feel-good chemicals released after exercise. We also know it's a source of theobromine, a stimulant that has a lasting relaxing effect.

But now there’s evidence to suggest that dark chocolate is less fattening when eaten at the start of a dark, depressing day.

According to endocrinologists in Venezuela, women who ate a 600-calorie breakfast, which included a piece of dark chocolate, lost more weight than those on a low-carb diet. Dr Daniela Jakubowicz attributed the success to kick-starting the body’s metabolism at the time of day it was most receptive to food.

So will it be muesli or a nugget?