Eating more fruits and vegetables during the day could help people sleep better that same night, according to new research from the University of Chicago Medicine and Columbia University. ALSO READ: Healthy lifestyle changes: What you should know The study found that participants who met the U.S. Centers for Disease Control and Prevention’s (CDC) daily recommendation of five cups of fruits and vegetables experienced a 16 percent improvement in sleep quality compared to those who ate none. ALSO READ: Why you should avoid late-night eating Researchers said the study revealed a strong link between diet and sleep quality. Participants who ate more fruits, vegetables, and complex carbohydrates such as whole grains experienced longer, uninterrupted periods of sleep, suggesting that what people eat during the day can directly influence how well they rest at night. Thirty-four healthy young adults recorded their daily food intake using a mobile app and wore wrist devices that tracked sleep. The scientists analyzed “sleep fragmentation,” a measure showing how often a person wakes up or shifts between light and deep sleep. Those with better diet quality showed lower sleep fragmentation, suggesting they slept more soundly. Previous research has connected poor sleep to cravings for high-fat and high-sugar foods; however, the new study shows the reverse, as daytime eating habits can affect how well people sleep that night. Researchers say the findings suggest that even small changes in diet could have an immediate impact on sleep and recovery. They plan to investigate whether the relationship between what we eat and how we sleep is important and to examine the biological mechanisms behind it in larger, more diverse groups. Expert weighs in on how diet affects sleep Private Kamanzi, the Chairman of the Rwanda Nutritionists Society (RNS), supports the research, noting that fruits and vegetables are rich in nutrients that enhance brain and heart health, promote digestion, and help the body rest better. According to Kamanzi, fruits and vegetables, when eaten raw or lightly cooked, boost the production of high-density lipoproteins (HDL), or “good cholesterol.” These lipoproteins support cardiovascular health and nourish the brain, keeping it refreshed and stable throughout the day. “When the brain is well-nourished, it can rest effectively at night, which contributes to better sleep,” he said. He added that while fruits and vegetables are not the main sources of omega-3 fatty acids, they play an important role in helping the body utilize these healthy fats obtained from other foods such as fish and certain oils. “When omega-3 is made active, the brain uses it efficiently to function well, and the balance gives the brain the ability to rest when a person sleeps,” Kamanzi explained. Kamanzi added that fruits and vegetables also promote good sleep by supporting digestion. For heavy meals, he noted that if eaten late in the evening can cause discomfort and disrupt sleep, while fruits and vegetables make digestion smoother and less demanding on the body’s energy, which allows the body to rest more effectively at night. The nutrition expert explained that digestion is one of the body’s most energy-intensive functions, and eating heavy or hard-to-digest meals at night can overwork the system and disrupt rest. He explained that when the body is busy processing food instead of recovering, sleep quality declines, which is why lighter, plant-based meals during the day can help promote better sleep at night. Kamanzi said that sleep problems such as insomnia can result from various underlying causes, including chronic conditions like hypertension, heart disease, depression, or pain. He advised identifying these root causes before recommending any dietary solutions, noting that effective advice on improving sleep must address each person’s specific situation. Kamanzi noted that lifestyle conditions, such as obesity, can affect sleep quality, explaining that overweight people often struggle to rest properly because breathing difficulties prevent the body from fully relaxing. He said poor eating habits and skipping meals can disrupt sleep, noting that people who skip meals during the day, either because they are busy or trying to lose weight, often eat heavily at night to compensate, which interferes with the body’s natural sleep cycle. “When you eat late at night after skipping meals all day, your body becomes like a factory that has a backlog of work. It must digest and metabolize food, produce energy, and operate all systems simultaneously. You can’t expect to rest when your body is still working.” He added that digestion, breathing, and heart function all require energy, so when the body has to process a large meal late at night, it remains active instead of resting completely.
