By studying women with polycystic ovary syndrome (PCOS), researchers from two Israeli universities were able to find out how meal timing and size can manipulate hormone levels. PCOS is a disorder that increases the amount of male sex hormones circulating in a woman’s blood and causes menstrual irregularities that can make it difficult for a woman to become pregnant. Sixty women with PCOS—all otherwise healthy and physically fit—were divided into two groups. The daily caloric intake for both groups was set at 1,800. Half of the women consumed their largest meal of the day—approximately 980 calories—during breakfast, while the other half ate it during dinner. Compared to those who chowed down in the evening, the morning feasters enjoyed a 50% drop in testosterone levels after 12 weeks. Levels of one reproductive hormone jumped 105% among the big breakfast eaters, and nearly half of those women started ovulating by the end of the study period—compared to just 20% of the dinner group. Eating more in the morning has been linked to health benefits like weight loss, stronger metabolism, and improved insulin sensitivity. And this upgrade in insulin sensitivity likely explains the reduction in male hormones among PCOS sufferers, says study coauthor Oren Froy, PhD, of the Hebrew University of Jerusalem. When you eat big in the morning, your diet schedule more closely aligns with your natural sleep-wake rhythms—a.k.a. your circadian clock, which helps regulate hormone production. As a result, your body is less likely to overproduce the wrong hormones, Dr. Froy adds. Even if you don’t suffer from a hormone imbalance related to PCOS, eating your largest meal in the morning will increase your fertility, Dr. Froy says. Try to consume roughly half of your day’s total calorie intake at breakfast. Choose foods high in protein (like Greek yogurt or eggs) and carbs (oatmeal) for better energy—and fertility—all day. MORE: High-Energy Foods That Jump Start Your Day
