It has long been hailed as the most crucial meal of the day, vital for getting the body going and preventing overeating later on.
But breakfast may not be so vital after all, if new research is to be believed.
Contrary to popular belief, the study found the first meal of the day had little impact on snacking or portion sizes later in the day. It also had no effect on metabolism.
The researchers, from the University of Bath, now suggest the better health of people who eat a good breakfast may be due to their general, wider, diet regime.
They found there was no change in metabolism after six weeks between those who ate nothing for breakfast and those who consumed 700 calories before 11am - 350 of these within two hours of waking.
The major difference was that those who abstained from breakfast ate fewer calories over the whole day.
This goes against the long-held theory that people who skip breakfast simply make up for it by gorging on food later on.
However, breakfast eaters were likely to expend more energy - around 442 calories - by being active, mainly in the morning after eating.
They also had more stable blood sugar readings, especially by the end of the trial.
The research idea came about because study leader James Betts - who admits to 'almost never having breakfast' - became weary of people telling him off for it.
'They'd say I should know better,' Dr Betts, a senior lecturer in nutrition, metabolism and statistics, told the New York Times.
He added: 'The belief that breakfast is ‘the most important meal of the day’ is so widespread that many people are surprised to learn that there is a lack of scientific evidence showing whether or how breakfast may directly cause changes in our health.
'It is certainly true that people who regularly eat breakfast tend to be slimmer and healthier but these individuals also typically follow most other recommendations for a healthy lifestyle, so have more balanced diets and take more physical exercise.
'Our randomised controlled trial allowed us to find out whether breakfast is a cause, an effect or simply a marker of good health.'
The research was published in the American Journal for Clinical Nutrition.
In another study published this month, researchers at the University of Alabama at Birmingham divided vounteers into three groups. One skipped breakfast, others always ate it and a third continued with their current regime.
Four months later, no-one in any group had lost much weight (1lb or so, if they had).