A small study finds when late-teen girls eat breakfast, it raises levels of a chemical in the brain’s reward center that may help them stop craving sweet foods and overeating during the rest of the day.

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“It used to be that nearly 100% of American adults, kids and teens were eating breakfast,” Prof. Leidy says, “but over the last 50 years, we have seen a decrease in eating frequency and an increase in obesity.”

Writing in the Nutrition Journal, a team from the University of Missouri in Columbia, notes that since over a third of American teenagers are overweight or obese and most of them will remain so in adulthood, focusing on young adults is an important way to prevent the perpetuation of the obesity epidemic.

The Centers for Disease Control (CDC) report many teenagers don’t eat breakfast and this likely increases the chance they will overeat and put on weight, they add.

Heather Leidy, an assistant professor of nutrition and exercise physiology, and colleagues, explain that the number of US teens struggling with obesity – which raises the risk they will have life-long health problems – has quadrupled in the last 30 years.

In their study of a small group of young women, they found eating breakfast increases levels of the brain’s reward chemical dopamine which is involved in controlling impulses. As these levels increase, they appear to reduce food cravings and overeating.

They suggest understanding how dopamine changes in the brain affect food cravings could helps us develop better ways to prevent and treat obesity.

Prof. Leidy says they found, “people experience a dramatic decline in cravings for sweet foods when they eat breakfast.”

“However,” she adds, “breakfasts that are high in protein also reduced cravings for savory – or high-fat – foods. On the other hand, if breakfast is skipped, these cravings continue to rise throughout the day.”

For their randomized, crossover study, the team recruited 20 overweight girls aged between 18 and 20 who normally skipped breakfast. Each participant underwent three types of 7-day eating patterns.

In one pattern, the participants ate a 350-calorie breakfast with normal amounts of protein, in another pattern they ate a 350-calorie breakfast with high protein, and in the third pattern, they skipped breakfast. After completing a 7- day pattern, they then had a 7-day “washing out period” before embarking on the next 7-day pattern.

In each of the 7-day patterns, on the morning of the seventh day, the girls underwent assessments, which included filling in food craving questionnaires. Fluctuation in dopamine was also assessed by checking dopamine metabolite homovanillic acid levels in regular blood samples taken through the morning.

The results showed both breakfast meals were followed by reduced cravings for sweet and savory foods and higher levels of dopamine metabolite.

Also, compared to a normal-protein breakfast, the high-protein breakfast tended to be followed by greater reductions in cravings for savory food and sustained levels in dopamine metabolite up until lunch.

Prof. Leidy explains that when we eat, our brain releases dopamine, which stimulates feelings of reward. This response is an important part of eating because it helps to regulate food intake. However:

“Dopamine levels are blunted in individuals who are overweight or obese, which means that it takes much more stimulation – or food – to elicit feelings of reward; we saw similar responses within breakfast-skippers.

To counteract the tendencies to overeat and to prevent weight gain that occurs as a result of overeating, we tried to identify dietary behaviors that provide these feelings of reward while reducing cravings for high-fat foods. Eating breakfast, particularly a breakfast high in protein, seems to do that.”

Although the study only included young women, the team believes the findings also apply to all adults.

More and more Americans are skipping breakfast, Prof. Leidy continues, and this is linked to food cravings, overeating and obesity:

“It used to be that nearly 100% of American adults, kids and teens were eating breakfast,” she adds, “but over the last 50 years, we have seen a decrease in eating frequency and an increase in obesity.”

In January 2014, Medical News Today also learned how metabolic syndrome and poor breakfast habits in childhood may be linked. Metabolic syndrome is a cluster of risk factors that are associated with heart disease, diabetes and stroke.

Researchers in Sweden found metabolic syndrome in adults was related to the type of breakfast those same adults had eaten as children.