Researchers announced that eating a big breakfast may lead to you piling on the pounds.
The study, which contradicts the dieting mantra that a big breakfast takes the edge off your appetite, found that those who pig out in the morning continue to eat heartily throughout the day.
The German researchers say those who want to lose weight should start watching what they eat from the minute they get up.
And those who can’t resist the lure of a bacon sandwich or a plate of pastries have to be more restrained later in the day if they want to win the battle of the bulge.
Volker Schusdziarra, of the Technical University of Munich, asked almost 400 men and women to eat normally but to note down everything they ate for 10 days.
He then checked how many calories were in each of their meals.
According to conventional wisdom, a big breakfast should curb appetite and so be followed by smaller meals over the rest of the day.
Instead, people tended to eat similar amounts for lunch and dinner, no matter how they started the day.
This meant that a big breakfast boosted overall calorie intake, the Nutrition Journal reports.
Dr Schusdziarra said that the conventional advice is based on artificial calculations and has little relevance to people’s everyday lives.
He told the Daily Mail: ‘It is said that if you eat a big breakfast you will eat fewer calories over the rest of the day but that is not true.
‘I always tell my patients to start reducing calories from breakfast time.
‘Saving calories at breakfast gives you a little bit more for the day itself – you can have a piece of chocolate in the evening.
‘If someone likes a high-calorie breakfast, then they have to save the calories in another meal.’
He suggests that dieters go easy on bread, toast and butter and tuck into eggs and cold ham for breakfast.
The researcher added that skipping breakfast all together does not necessarily lead to weight gain, with many people of a healthy weight regularly not eating the meal.
Sian Porter, of the British Dietetic Association, said it is important to make time for breakfast.
She said: ‘It has been shown that people who eat breakfast have more balanced diets than those who skip the meal, are less likely to be overweight, lose weight more successfully and have a reduced risk of certain diseases.
‘It is better to eat something than nothing, so make sure you have things to hand you can grab, like a banana, fruit salad, or yoghurt with muesli for those mornings when you are in a spin.’