It's a myth that eating a large breakfast means consuming fewer calories during the day, according to researchers in Germany.
The study, published in Nutrition Journal, showed that people still eat the same amount at lunch and dinner.
The scientists suggest reducing breakfast calories could help people lose weight.
The British Dietetic Association said eating breakfast was important for a balanced diet.
Starting the day with a hearty breakfast has often been linked with weight loss.
Not cutting back
The team at the University of Munich followed nearly 400 people for a fortnight.
The patients kept a diary of what they ate, at what time and how much it weighed.
Some had large breakfasts, some small and some skipped the meal.
People who had a big breakfast, on average 400 calories larger than a small one, consumed around 400 more calories in a day.
Dr Volker Schusdziarra, lead researcher, said: "The results of the study showed that people ate the same at lunch and dinner, regardless of what they had for breakfast."
Experts still say that breakfast has an important role to play.
Sian Porter, spokeswoman for the British Dietetic Association, said: "It has been shown that people who eat breakfast have more balanced diets than those who skip this meal, are less likely to be overweight, lose weight more successfully and have reduced risk of certain diseases.
"Missing breakfast may lead you to snack on less healthy foods later on in the morning and you won't necessarily catch up nutritionally later in the day if you skip breakfast."