Breakfast helps the body process sugars more efficiently—and it's having high levels of blood sugars that can lead to cardiovascular disease and type 2 diabetes.
To test the theory, researchers from the University of Bath asked a group of 49 adults—29 of whom were lean and the others obese—to either eat a high-carb breakfast every day for six weeks, or to fast until noon.
The participants' metabolism, body composition, and appetite markers and responses were measured before and after the study, and the researchers found that breakfast affected body fat cells and the way they were able to process sugars.
This is especially important for people who are obese as their fat cells don't respond well to insulin, which the body releases in order to break down sugars, and so fasting actually increases their chances of getting diabetes or heart problems. In fact, the ability to break down sugars is proportional to the total amount of body fat, so a fat person is less able to deal with sugars than a lean person.
The researchers say that the participants were all eating a high-carb breakfast, and so they can't be sure if similar benefits would be seen if they'd instead eaten a high-protein meal.