by Jenna Koroly, MS, RD, CSOWM, CDN
There is a wealth of research to support the relationship between the types of foods we eat and chronic disease management and prevention, such as in cardiovascular disease (CVD) and diabetes. More recently, studies have looked into how the timing of our eating may influence health due to our circadian rhythms. For example, research has found skipping breakfast, eating frequently throughout the day, eating more at dinner, and eating late at night to be association with increased inflammation, increased risk of obesity and diabetes, and decreased cardiometabolic health [Jakubowicz et al., 2017; Wittig et al., 2017; Ren et al., 2021; Kutzuma et al., 2014; Nas et al., 2017; Jakubowicz et al., 2019 as cited in reference i]. One study also showed that higher energy intake at breakfast and lower energy intake at dinner was associated with increased long-term survival in those with diabetes [Han et al., 2020 as cited in reference i]. In the below study, the authors examine how the timing of eating specific foods may be related to CVD and all-cause mortality in individuals with diabetes [i].
Study
The association of consumption time for food with cardiovascular disease and all-cause mortality among diabetic patients
Journal: The Journal of Clinical Endocrinology & Metabolism
This study included 4642 individuals with diabetes who were part of the National Health and Nutrition Examination Survey (NHANES) from 2003-2014. Two 24-hour dietary recalls on nonconsecutive days (3-10 days apart) were collected. The authors divided intake into 3 separate periods: forenoon (breakfast and snacks between breakfast and lunch), afternoon (lunch and snacks between lunch and dinner), and evening (dinner and snacks after dinner). The authors also conducted sensitivity analyses on potential confounders including overall diet quality, skipping breakfast, <2 years of survival, <30 years of age, and <30 years of age at time of diabetes diagnosis. Outcomes were CVD and all-cause mortality.
Findings
The authors found:
- Participants in the highest quantile of intakes of potato, starchy vegetable, and tomato in the forenoon had a lower mortality risk from CVD and all-causes compared to those in the lowest quantile.
- Participants in the highest quantile of intake of whole grains in the afternoon had a lower mortality risk from CVD and all-causes compared to those in the lowest quantile.
- Participants in the highest quantile of intakes of dark vegetables and milk in the evening had a lower mortality risk from CVD and all-causes compared to those in the lowest quantile.
- Participants in the highest quantile of intake of processed meat in the evening had a higher mortality risk from CVD compared to those in the lowest quantile.
- Moving 0.1 serving potato or starchy vegetable from afternoon or evening to forenoon, 0.1 serving dark vegetable from afternoon to evening, and 0.1 serving whole grain from forenoon to afternoon decreased risk of CVD mortality.
For the Patient and Caregiver
Our circadian rhythm is our internal clock that repeats every 24 hours, and is related to natural processes that respond to light and dark. Circadian rhythms have an important impact on our hormones, such as insulin, melatonin, and leptin (a fullness hormone), and digestion. Because of this relationship, timing of foods may be helpful to promote overall health and chronic disease prevention and management. It may be beneficial to aim for higher carbohydrate foods (such as potatoes and whole grains) in the morning and afternoon rather than the evening due to their greater influence on our insulin response. It also may be beneficial to aim for vegetables and melatonin-producing foods (such as milk, pistachios, mushrooms, and fish) in the evening. It is important to note, however, that more research is needed in this area.
For the Healthcare Team
There are a number of mechanisms that may explain the impacts of specific timing of certain foods. First, it has been shown that insulin sensitivity and secretion have a biological rhythm, with high levels in the forenoon which gradually decrease throughout the day into night [Poggiogalle et al., 2018 as cited in reference i]. This may partially explain the benefit of potato and starchy vegetable intake in the morning, and whole grain intake in the afternoon based on the glycemic index. Next, it has also been found that gut microbes have an internal circadian pattern, with more production of short-chain fatty acids at night compared to daytime, which may partially explain the benefit of dark vegetable intake in the evening [Man et al., 2020; Liang et al., 2017; Tahara et al., 2018; Canfora et al., 2015; Hernandez et al., 2019 as cited in reference i]. The benefits of milk in the evening may be related to increased melatonin and improved sleep, while the drawbacks of processed meats in the evening may be related to microvascular disorder involving blood pressure and pulse pressure [Tadida et al., 2017 & Yang et al., 2019 as cited in reference i].
Reference:
[i] Jiang W, Song Q, Zhang J, Chen Y, Jiang H, Long Y…Wei W (2022). The association of consumption time for food with cardiovascular disease and all-cause mortality among diabetic patients. The Journal of Clinical Endocrinology & Metabolism XX, 1-10. https://doi.org/10.1210/clinem/dgac069
Interesting study. The movement of higher glycemic foods to forenoon makes sense given what we know of insulin sensitivity. I’m not clear on why whole grains are better to have in afternoon vs forenoon. I would also thing green vegetables are good any time of day. Thanks for this interesting information nicely summarized, as always, Jenna
Thank you for reading! It is interesting that there was a significant difference (and benefit) between whole grains in afternoon vs forenoon — the authors surmise it may be related to a lower glycemic index of whole grains compared to potatoes. There are likely other factors at play apart from only glycemic index (such as gut microbes) that support a specific benefit of green vegetables in the evening.