There are how many calories in my sandwich?
An apple has 50, while a slice of apple pie with cream has more than 500 -- so do you know how many calories you've really scoffed today?
Diet docs recommend men stick to around 2,500 a day and women around 2,000 to stay in shape.
But a new survey has revealed that 72pc of us have no clue how many calories we really consume.
Now that could all be about to change after the Food Safety Authority of Ireland (FSAI) revealed plans to put calories on menus within six months.
And with one-in-three Irish people now overweight, eating out could soon help shift the pounds -- not pile them on, bosses say.
"It's a simple concept that will help consumers make healthier choices, eat smaller portions and enjoy food without overeating," says Minister for Health Dr James Reilly.
"I strongly believe that calorie menu labelling has the potential to have a major effect on our obesity crisis.
"Almost one-quarter of calorie intake of Irish adults under 65 is consumed outside the home," adds Dr Mary Flynn, Chief Specialist Public Health Nutrition, FSAI. "The consumer does not know what ingredients are used and how they are prepared, so calorie menu labelling is vital if people are to make more informed choices about what they eat."
Invented at the turn of the 20th Century by American chemist Wilbur Atwater, calorie-counting basically works by balancing the number of units of energy -- or calories -- you eat with the number you burn off through exercise.
Already, Insomnia Coffee Company, McDonald's and Carton House in Maynooth have signed up to the voluntary scheme -- estimated to set eateries back around €5,000 a year.
"Anything that makes people more aware of what they are eating is a good thing," says David Greaney of Refit Yourself, a live-in fitness and nutrition camp in Woodenbridge, Co Wicklow.
"For instance, if someone sees that a full Irish breakfast contains 1,400 calories -- more than half the recommended daily intake for men -- they might consider going for a healthier option."
With one-third of the population sporting muffin tops, can broadcasting the number of calories in a muffin really make any difference to the nation's waistline?
In the States, where calories are on the menus of some restaurants by law, one study showed that only 15pc of people actually paid any attention to them.
And even then, they ate just 106 less calories on average than those who completely ignored the information.
"The problem with calorie-counting is that it doesn't give the whole picture," says nutrition consultant Lynda McFarland.
"Fat is a prime example," she adds. "As a macro-nutrient, it's vital for healthy skin, hair, mood and concentration.
"Unfortunately, people usually only look at its calorie content.Most low-cal foods replace the fat with sugar -- leading to an increase in sugar-related diseases."
Meanwhile, scientists estimate that the amount of calories people think they eat and expend and the amount they're actually using could be out by as much as 25pc.
So could putting calories on menus ironically compound Ireland's 'calorie delusion'?
"People often get bogged down by calculating what they eat down to the last calorie," says David Greaney of Refit Yourself. "But there's no exact calorie count for a cup of coffee with a drop of milk and half a spoon of sugar or a handful of peanuts, for example."
'It would be impossible for a cook-to-order restaurant like ours to put accurate calorie counts on the menu," says Evan Doyle, co-owner of The Strawberry Tree restaurant at The Brook Lodge & Wells Spa in Wicklow.
"Dishes can change every time they are cooked depending on the individual flair of the chef."
"It's easy to assume that by eating fewer calories you're guaranteed to lose weight," adds Greaney.
"But when the body is in a catabolic state, it actually increases the storage of energy as fat as a survival mechanism.
"Simply counting calories should not be seen as a quick fix for weight loss," he adds. "Ultimately, there is no substitute for healthy eating and exercise."