The Benefits of Breakfast Consumption to Combat Obesity and Diabetes in Young People

Weight Gain and Obesity

In the past 10 years, numerous, large cross-sectional and prospective studies have examined the relationship between obesity and breakfast skipping.^{10,11,13,18,20} These studies indicate that there has been a substantial decline in breakfast consumption in the past 20 years, which has closely paralleled the significant increase in obesity.^{10,11,13,17,18,20} Breakfast frequency was found to be inversely associated with BMI in a dose-dependent manner, such that the fewer the number of breakfast eating occasions, the greater the increases in BMI.^12,13,17 Furthermore, overweight and obese young people are 2 times more likely to skip breakfast than their normal-weight counterparts.^17,21 When grouped according to frequency of breakfast consumption, those who skip breakfast have an increased prevalence of being obese, having higher BMI percentiles, and having higher BMI z scores when compared with those who habitually consume the morning meal.^10,17 This common, yet unhealthy, dietary behavior of skipping breakfast is disconcerting at this sensitive life stage because of the fact that dietary habits and practices are developed and become solidified during adolescence and will continue throughout adulthood, further affecting body weight and overall health and well-being. ²

One of the key studies surrounding breakfast and obesity prevention/treatment pertains to the men and women who are part of the National Weight Control Registry (NWCR). ²² To date, the NWCR has followed more than 5000 individuals who have lost at least 13.6 kg for at least 1 year, with the goal of identifying the characteristics of individuals who have succeeded at long-term weight loss. ²² When examining the dietary habits of these individuals, the majority (78%) reported eating breakfast on a daily basis, whereas only 4% never eat breakfast. ²² Taken together, these data suggest that a strong protective effect exists with the daily consumption of breakfast to prevent weight gain and obesity.

Diet Quality

Along with the effects of breakfast on body weight management, observational studies indicate that those who frequently eat breakfast consume a higher-quality diet, including more fruits, vegetables, milk, and whole grains, compared with those who skip breakfast.^10,11,23-26 This leads to an increased consumption of key vitamins (vitamins A, C, B-6, B-12, thiamin, riboflavin, niacin, and folate), minerals (calcium, phosphorus, magnesium, iron, and potassium), and dietary fiber but lower amounts of dietary fat and cholesterol.^10,11,23-26 Furthermore, breakfast consumers eat fewer unhealthy snacks, including soft drinks, sweets, and salty snacks, all of which are caloric dense, high in saturated fat, and/or high in sugar.^25-27

Glucose Control

Several acute experimental studies examined the effects of breakfast consumption on glucose and insulin metabolism. In a study by Farshchi et al, ²⁸ 10 healthy, lean breakfast-consuming women were asked to follow 14 days of skipping breakfast or consuming a 500-kcal breakfast meal each day. Skipping breakfast led to greater daily energy intake versus eating breakfast, despite the additional 500 kcal consumed with breakfast. ²⁸ This study also found that breakfast skippers had higher fasting total and LDL cholesterol along with reduced insulin sensitivity to a breakfast test meal compared with breakfast eaters. ²⁸ These data were confirmed by Jovanovic et al, ²⁹ who examined the effects of skipping breakfast in breakfast-consuming obese, type 2 diabetic adults. Skipping breakfast, rather than consuming a 650-kcal breakfast, led to compromised glucose control at the next meal. ²⁹ Specifically, when breakfast was skipped, there was a much larger rise in plasma glucose in response to a standardized lunch meal compared with when breakfast was consumed. ²⁹

Appetite Control and Satiety

A key mechanism surrounding the improvements in energy intake and body weight management with breakfast consumption includes the beneficial changes in appetite control and satiety when the morning meal is consumed. For example, data from our lab indicate that the addition of a 500-kcal breakfast leads to significant postbreakfast reductions in perceived appetite, increases in perceived fullness, increases in the satiety hormone PYY (peptide YY), and decreases in the neural activations in brain regions controlling food motivation and reward in habitual breakfast-skipping adolescents.^30,31 Furthermore, the addition of breakfast leads to a reduction in energy intake at lunch. ³⁰

Glycemic Index (GI)

Most experimental breakfast studies to date incorporate carbohydrate-based RTECs and examine the effects of low- versus high-GI breakfast foods.^30-35 Three acute, randomized cross-over design studies assessed the effects of low- versus high-GI breakfast meals on postbreakfast appetite, satiety, glucose control, and subsequent (ie, lunch) intake.^30-32 Although Pereira et al ³⁰ and Warren et al ³² found reduced perceived hunger following the low- versus high-GI breakfast, Brindal et al ³¹ found no differences in perceived hunger and/or satiety. Some ³² but not all^30,31 found significant reductions in lunch energy intake following the low- versus high-GI breakfast meals, wherein the low-GI breakfast meals led to improved glucose control when compared with the high-GI breakfast meals.^30,31 Three long-term studies have also been completed. Clark et al ³⁴ found improved postbreakfast glycemic, insulinemic, and free-fatty acid responses following 3 weeks of consuming a low-GI versus high-GI breakfast. However, Henry et al ³³ and Tsihlias et al, ³⁵ whose studies were 10 weeks and 24 weeks long, respectively, found no differences when comparing chronic consumption of low- versus high-GI breakfast meals.

Conflicting findings might be a result of the varying dietary components within and between the breakfast meals. For example, whereas some studies developed low-GI meals by incorporating fiber,^34,35 others primarily used a combination of increased fiber and fat while reducing carbohydrates^30-32 or matched macronutrient and fiber but varied sugar and carbohydrate type. ³³ Thus, further research is needed to formulate a consensus on the dietary components that alter GI and their effects on obesity and type 2 diabetes.

Dietary Protein

Dietary protein is critical to the health and well-being of individuals of all ages but even more important in growing children and adolescent. ³⁶ Whereas the recommended dietary allowance for protein intake for adults is defined by the Food and Nutrition Board as 0.80 g protein/kg/d, adolescents (ages 15-19 years) are prescribed a daily intake of 0.85 g protein/kg/d (10%-15% of daily intake as dietary protein). ³⁶ In adults, higher-protein diets, defined as those containing 25% to 40% of daily intake as protein, have led to greater reductions in total energy intake,^37,38 body weight,^37,38 and fat mass ³⁹ along with a greater preservation of lean body mass ⁴⁰ compared with eating10% to 15% of daily intake as dietary protein. Along with these benefits, protein-rich diets lead to acute and long-term alterations in appetite control and satiety. Specifically, single meals and overall diets rich in dietary protein lead to postmeal, daily, and/or long-term reductions in feelings of perceived hunger, increases in perceived fullness (satiety), reductions in the hunger hormone ghrelin, and increases in the satiety hormone PYY.^41-43

To investigate the incorporation of increased dietary protein at breakfast, we compared satiety response when protein was consumed at breakfast, lunch, or dinner. ⁴⁴ Dietary protein consumed at breakfast led to greater initial and sustained feelings of fullness (satiety) compared with that consumed at lunch and dinne. ⁴⁴ These data support the inclusion of increased dietary protein at the morning meal.

We examined whether the addition of a normal-protein versus high-protein breakfast beneficially alters appetite control, satiety, food motivation/reward, and subsequent food intake in habitual breakfast-skipping adolescents.^45,46 Both breakfast meals were 500 kcal; the normal- protein breakfast contained 15% of the meal’s calories as protein (ie, 18 g protein), whereas the high-protein meal contained 40% of the meal’s calories as protein (ie, 50 g protein).^45,46 Regardless of protein content, the addition of breakfast led to increased satiety, increased perceived fullness, and increased PYY concentrations throughout the morning compared with skipping breakfast. ⁴⁵ Breakfast consumption also led to prelunch reductions in brain activation in regions controlling food motivation and reward. ⁴⁶ However, the high-protein breakfast provided additional benefits through reductions in morning perceived appetite compared with the normal-protein breakfast. ⁴⁵ Furthermore, the high-protein breakfast led to greater reductions in neural activation associated with food cravings and executive control compared with the normal-protein breakfast. ⁴⁶ Subsequent (ie, lunch) energy intake was also lower following the high-protein breakfast versus skipping breakfast or consuming the normal-protein breakfast. Recent, preliminary findings from our lab found that a breakfast containing 35 g of protein led to increased satiety and reduced reward-driven eating behavior compared with a normal protein breakfast or breakfast skipping. Thus, these findings suggest that the addition of a protein-rich breakfast might be an effective strategy to improve appetite control and satiety in young people.