Nutritionalists have been underscoring the importance of eating breakfast for many years, but many people are still inclined to go about their daily business on an empty stomach - a habit that may mean they are more likely to give blood sugar levels a boost by snacking on unhealthy foods later in the morning.
In the first of the new studies, both of which are published in the Journal of the American Dietetic Association, researchers from Michigan State University analyzed dietary data from 4218 men and women aged 19 and over gathered as part of the 1999-2000 National Health and Nutrition Examination Survey. They wanted to see whether there was statistical evidence to support the association between breakfast consumption and body mass index (BMI).
They found that women who ate breakfast were more likely to have a normal BMI (below 25) than non-breakfast eaters - as were women who ate ready-to-eat cereals (RTEC) compared with non-RTEC eating women.
Breakfast eaters were more likely to be older, female, white, nonsmokers, regular exercisers, who were also trying to control their weight. Women who ate breakfast were found to have a higher daily energy intake than non-breakfast eaters.
Energy intake from fat was significantly lower in both men and women eating ready-to-eat cereals (RTEC) compared with non-RTEC consumers, but RTEC consumers also consumed more energy from carbohydrate than their non-RTEC counterparts.
These findings prompted the researchers to conclude that meal type is an important factor.
"RTEC breakfast consumption, associated with a desirable macronutrient profile for preventing obesity, predicted weight status in women, but not in men," they wrote.
Meanwhile, researchers from the Maryland Medical Research Institute looked into breakfast and cereal consumption of 2379 girls between ages 9 and 19 years, and the association with BMI and intake of dietary fat and the important nutrients fiber, calcium, cholesterol, iron, folic acid, vitamin C, and zinc.
They used data from the National Heart, Lung, and Blood Institute Growth and Health Study, a longitudinal biracial observational cohort study with annual three-day food records.
Frequency of consumption of breakfast (including cereal vs other foods) and cereal; BMI; and dietary fat, fiber, calcium, cholesterol, iron, folic acid, vitamin C, and zinc.
Lead researcher Bruce Barton called the findings "striking", since girls were less likely to eat breakfast as they grew older, but the days on which they did eat breakfast they had a higher intake of calcium and fiber.
"From the age of 13 on, you can clearly see the girls who frequently eat cereal splitting from the majority of girls who do not eat cereal and are gaining more weight," he said. "For their age, significantly more girls who ate cereal had a normal body weight compared to those who didn't eat cereal."
In general and after adjusting for energy intake, cereal consumption was linked to a higher nutrient intake, and decreased fat and cholesterol intake. Cereal eating was predictive of lower BMI.
"Cereal consumption as part of an overall healthful lifestyle may play a role in maintaining a healthful BMI and adequate nutrient intake among adolescent girls," concluded Barton and his team.
The study was funded in part by General Mills, which recently switched all its breakfast cereal products to healthier wholewheat variants. However cereal makers have come in for widespread criticism in recent times for marketing sugar-laden, processed foods to children.
In the United States, childhood obesity and overweight is a major problem. According to the National Institutes of Health, an estimated 16 percent of children and adolescents aged six to 19 are overweight - a 45 percent increase over figures obtained a decade ago.