“Healthy eating is not only what you eat, but also how much you eat and when,” says Kaylyn Koons.
Koons, a doctoral candidate at the University of Florida, is the lead author on a recently-released informational resource on chrononutrition from the Institute of Food and Agricultural Sciences. Chrononutrition is an emerging field of study that looks at how diet and the body’s 24-hour internal clock interact.
“The field of nutrition overall is a relatively new field,” Koons tells The Packer, giving the example of the discovery of vitamins, which occurred roughly from the mid-19th century through the mid-20th century.
“As we are starting to learn more about nutrition,” Koons says, “we are beginning to understand how other aspects of biology (i.e. circadian rhythm) interact with dietary patterns.”
Chrononutrition basics in brief
According to the University of Florida/Institute of Food and Agricultural Sciences resource, the field of chrononutrition kicked off in 1967 with Franz Halberg, a Romanian-born physician. The idea of the field is based on the idea that the sleep and wake cycle — one’s circadian rhythm — regulates functions such as metabolism and digestion. This means how someone schedules meals throughout the day can impact their weight, body mass index and likelihood of developing various health issues.
“Chrononutrition is an approach to diet that focuses on the timing of food intake in alignment with the body’s natural circadian rhythms,” the UF/IFAS guide summarizes. “Chrononutrition examines three primary aspects of eating behaviors: timing, frequency and consistency. These aspects play essential roles in maintaining metabolic health, weight management and overall well-being.”
Despite beginning almost 60 years ago, chrononutrition is still considered an emerging field.
“One challenge the field has faced in advancing knowledge and research on chrononutrition is the difference in circadian rhythms between animals and humans,” Koons explains. In most research settings, using animal models — such as testing on mice or rats — comes before studies on people. But research animals often have different circadian rhythms than humans do.
“For example, mice are nocturnal, so feeding schedules and other interventions must be timed accordingly to ensure relevance in translating findings to humans,” Koons says.
What is known versus what we need to learn
Though it is an emerging field with some obstacles to research, there have been plenty of findings, and the UF/IFAS guide gave several examples of chrononutrition in action.
For example, regularly skipping breakfast — something the resource called a “chrononutrition behavior” — has been “associated with lower diet quality, increased risk of obesity and many chronic diseases throughout the lifespan.”
Eating late in the day (after 8 p.m.) has similarly been “linked with poorer food choices, overeating, snacking at night and experiencing metabolic disorders,” according to the guide.
Koons explains that findings of “lower diet quality” and “poorer food choices” generally reference the Healthy Eating Index from USDA’s Food and Nutrition Service. The HEI score is a tool to quantify diet quality in the U.S. The HEI score is out of a maximum of 100. Twenty points of that total maximum come from four produce-related categories: total fruits, whole fruits, total vegetables, and greens and beans.
The paper does not identify strong evidence linking chrononutrional behaviors to increased consumption of fresh produce, Koons says.
“Therefore, it’s unclear whether favorable chrononutrition behaviors would promote greater consumption of fresh produce,” she says. “This would be an interesting area for future research, especially with the consideration of chrononutrition.”
The impact of culture on chrononutrition
Culture can have a big impact on details around food and meals that impact types of food and when they are eaten — or not eaten, as the case may be.
“The Western diet, low in fruits, vegetables and whole grains, and high in saturated fat and processed foods, has been well established to increase risks of chronic diseases,” Koons says. She also points to what she calls the “grind mentality” of Western culture, with its long hours, as potentially contributing to negative chrononutritional behaviors.
“Extended work hours can present time-related barriers that impact the amount of time one can spend engaging in healthful dietary practices such as grocery shopping, cooking and regular meal timing,” she says. “Arguably, the most significant obstacle in Western culture is the attitude towards food and meals, changing the narrative from being a task to complete to an opportunity for nourishment.”
Koons contrasts the Western diet and meal culture to the Mediterranean region, both its diet and lifestyle patterns.
“This dietary pattern includes a high intake of fruits, vegetables, whole grains, legumes, nuts and healthy fats (particularly olive oil), along with consumption of lean meat such as fish and poultry,” she says. “In addition to food choices, the Mediterranean diet encourages regular, balanced meals, community engagement through shared meals and routine physical activity.”
The UF/IFAS guide was published as an educational resource aimed at summarizing current research findings on chrononutrition for nutrition educators, Koons says. But it could also be a tool for consumers interested in identifying potentially negative chrononutrional behaviors they may be engaging in.
“Most eating patterns are often deeply ingrained in habits which can be difficult to change,” Koons says. “For those who seek guidance in improving their chrononutrition or food choices, I recommend working with a registered dietitian who can provide personalized guidance and strategies tailored to each individual’s needs.”
