ASN Journals Present the Latest Findings in Chrono-Nutrition
We know that what we eat matters, but does when we eat also matter? Research findings in the nascent field of chrono-nutrition suggest that the answer may be yes.
Chrono-nutrition looks at how the timing of eating events affects nutritional status and health outcomes. Specifically, nutrition scientists have explored the impact of meal frequency, meal skipping, the timespan between the first and last daily eating event, periodic fasting or energy restriction, and the distribution of caloric intake throughout the day. These investigations are beginning to build a body of evidence demonstrating how the timing of food intake may have its own independent effect on health outcomes, from weight management to metabolism to cancer risk.
The American Society for Nutrition (ASN) has been at the forefront of this growing area of nutrition research, fostering and publishing original research studies and reviews in the field of chrono-nutrition. Below are highlights of chrono-nutrition investigations published in all four ASN journals.
The Effects of Ramadan Fasting on Activity and Energy Expenditure, The American Journal of Clinical Nutrition
Ramadan fasting is not associated with a significant change in resting metabolic rate nor total energy expenditure.
Fasting during the month of Ramadan entails abstinence from any eating and drinking between sunrise and sunset, resulting in a major shift in meal patterns. Nader Lessan et al. wanted to know what impact Ramadan fasting might have on resting metabolic rate and total energy expenditure. To conduct their research, the authors recruited 29 healthy men and women without obesity who observed Ramadan, taking anthropometric and resting metabolic rate measurements weekly during Ramadan and then once sometime between one and two months after Ramadan. Interestingly, the authors found that Ramadan fasting is not associated with a significant change in resting metabolic rate nor total energy expenditure. According to the authors, “reported weight changes with Ramadan in other studies are more likely to be due to differences in food intake.” While this study focused on the effects of Ramadan fasting, the results “may have implications to dietary restriction programs that promote skipping and spacing meals.”
Meal Frequency and Timing Are Associated with Changes in Body Mass Index in Adventist Health Study 2, The Journal of Nutrition
Eating less frequently, consuming breakfast, and eating the largest meal in the morning may be effective long-term preventive tools against weight gain.
ASN member Hana Kahleova et al. analyzed data from more than 50,000 men and women aged 30 and above who participated in the Adventist Health Study 2 to determine the relationship between meal frequency and timing and BMI. The results of their study suggest that “eating less frequently (and eating no snacks), consuming breakfast, and eating the largest meal in the morning may be effective long-term preventive tools against weight gain.” Study results also demonstrated that participants who typically had the longest overnight fasts (18 hours or longer) were more likely to have a lower BMI compared to participants who had shorter overnight fasts. The authors did point out that while meal patterns associated with a lower BMI were generally more healthful, certain individuals, particularly older adults with chronic disease, may need to choose meal patterns that are more likely to promote weight gain.
A Population Level Descriptive Analysis of Diet Quality According to the Duration of Daily Eating Period: NHANES 2007–2016, Current Developments in Nutrition
Individuals whose daily eating duration was between 8 and 16 hours had the highest diet quality.
The time interval between the first and the last intake of food during the day (i.e., daily eating duration) has been identified as a factor that may impact health. Valeria Elahy et al. wanted to investigate further to determine whether there was a relationship between daily eating duration and diet quality, using the Healthy Eating Index as a measure of diet quality. To conduct their research, the authors analyzed data from more than 20,000 adult men and women who had completed dietary recalls as part of the 2007–2016 National Health and Nutrition Examination Survey (NHANES). They found that individuals whose daily eating duration was between 8 and 16 hours had the highest diet quality. Whether the eating duration was closer to 8 hours or to 16 hours did not affect diet quality. On the other hand, those whose daily eating duration was less than 8 hours or more than 16 hours had lower diet quality. This pattern was consistent across sub-groups, but with significantly higher diet quality among participants who ate breakfast, were not current smokers, and had higher family income to poverty ratios.
Data are currently insufficient to support claims about the anticancer effects of intermittent energy restriction and intermittent fasting.
There is increasing interest in the possible anticancer effects of intermittent energy restriction or intermittent fasting. This review, conducted by ASN member Michelle N. Harvie et al., analyzed animal studies, as well as the limited number of human studies, that assessed the effect of intermittent energy restriction or intermittent fasting compared to continuous energy restriction on tumor growth rates and cancer biomarkers. While the authors did see some encouraging evidence, they did, however, note that the limited data “are currently insufficient to support claims about the anticancer effects of intermittent energy restriction and intermittent fasting.” In conclusion, the authors believe that “high-quality research comparing intermittent energy restriction and intermittent fasting with continuous energy restriction are required to ascertain any true health benefits and anticancer effects.”
To discover more studies in the burgeoning field of chrono-nutrition, visit ASN’s Special Collection, Nutrition, Sleep & Time. In addition to chrono-nutrition, this Special Collection, also explores the inter-relationships between nutrition and sleep.
If you are conducting research in chrono-nutrition, please consider publishing your results in an ASN journal. Whichever journal you choose, our editorial team will ensure that your findings are disseminated quickly around the world, advancing our understanding of this nascent field and giving your research the full impact it deserves.