1. Time Restricted Feeding (TRF): Why would the time of day you eat effect your weight and reduce inflammation ?
Recent research has found that when animals eat during the day could be a key factor in weight loss (or gain).
Twelve studies of time restricted eating were identified with daily fasting intervals ranging from 12 to 20 hours, with variability in coordination with light/dark phases and composition of food. In mice, time-restricted feeding was associated with reductions in body weight, total cholesterol,triacylglycerol, glucose, insulin, interleukin 6, and TNF-α as well as improvements in insulin sensitivity. It is notable that these health outcomes occurred despite variable effects of intermittent fasting on weight loss. Patterson et al 2015.
Research in animals highlights the potential importance of synchronizing intermittent fasting regimens with daily circadian rhythms. Animals given unlimited access to a high-fat diet eat frequently throughout the night and the day, disrupting their normal nocturnal feeding cycle. These mice fed an unrestricted high-fat diet develop obesity, diabetes, and metabolic syndrome. However, it was unclear whether these diseases result from the high-fat diets, disruption of circadian rhythms, or both. Mice whose feeding was restricted to normal nocturnal eating times consumed equivalent energy but were protected from obesity, hyperinsulinemia, hepatic steatosis, and inflammation. Patterson et al 2015 , M Hatori et al 2012 and Chaix, 2014, S Gill 2015.
The Effects of Time Restricted Eating on Human Beings.
Crossover studies found significant reductions in weight (although these studies did not prescribed or measured physical activity). In a study among 29 normal-weight men, a prescribed night-time fasting interval of more than 11 hours resulted in a 1.3% weight loss. Another crossover study compared the effect of consuming one afternoon meal per day for 8 weeks and reported 4.1% weight loss in comparison to an isocaloric (similar calorie values) diet consumed as three meals per day. One meal per day was also associated with reductions in fasting glucose and improvements in cholesterol levels. Whereas self-reported hunger was higher in the morning for those consuming one meal per day, this fasting regimen was considered acceptable because there were no mean changes in tension, depression, anger, vigor, fatigue, or confusion.
Although clearly limited, results from these studies of time-restricted feeding are consistent with research in animals indicating that incorporation of regular fasting intervals and eating in accordance with normal daily circadian rhythms (ie, daytime hours in human beings) may be important for maintaining optimal metabolic function. It is well known that in human beings, even a single fasting interval (eg, overnight) can reduce basal concentrations of metabolic biomarkers (such as insulin and glucose) associated with chronic disease. Patients are required to fast for 8 to 12 hours before blood draws to achieve steady-state fasting levels for many metabolic substrates.
Prolonged nightly fasting may be a simple, feasible, and potentially effective disease prevention strategy at the population level. Overall evidence suggests that intermittent fasting regimens may be a promising approach to lose weight and improve metabolic health for people who can tolerate intervals of not eating, or eating very little, for certain hours of the day or days of the week. Patterson et al 2015
C R Marinac has also carried out a number of studies on the impact of time restricted dieting on women and found that frequency and circadian timing of eating may influence biomarkers of inflammation and insulin resistance associated with breast cancer risk (C R. Marinac 2015).
There have been positive early findings on the effects of intermittent fasting regimens on inflammation and the immune system (including relieving symptoms of MS) which scientists are currently attempting to explain. In mice, fasting and feeding has been found to elevate the number of stem cells and their regenerative capacity. Early results suggest this could reboot the immune system. Y Choi et al 2016. In older mice, this strategy promotes the development of new neuronal cells, i.e. it may have neurorestorative capacity.
One theory is that fasting diets starve the body of sugars and change the metabolism by switching off, or lowering, circulating levels of insulin….these diets cause people to become ketotic. Ketones may have several benefits to health, including brain health.
Other explanations for the effects of time restricted diets focus on alignment with the body’s circadian rhythms. Eating happens at times when the body is more efficient at breaking down foods. The metabolic system evolved to allocate energy resources at different times of day. Exhaustive research over the past few decades has begun to elucidate the full range of human physiology that is regulated in synchrony with the solar day. With regard to neuronal function, this includes not only the control of sleep and wakefulness, but also modulation of mood, cognition, sensory acuity, breathing rate and body temperature (Schmidt et al., 2007).
Nearly all aspects of digestion and detoxication – from gastric emptying time to fat processing and xenobiotic degradation by the liver – are under circadian control (Dallmann et al., 2014). Yu Tahara and Shigenobu Shibata have explored nutrition and diet as potent regulators of the liver clock, and circadian rhythms can also influence metabolism.
Many aspects of the circulatory and immune systems, including heartbeat and blood pressure, vascular leakage and even plasma composition, are also regulated daily (Dallmann et al., 2012; Scheiermann et al., 2013). S A Brown 2014.
2. The influence of microbiota
Another possible explanation could be the gut microbiota’s influence on biomarkers of inflammation due to the microbiota’s intervention in the relationship between circadian rhythms and redox.
Circadian rhythms are increasing being found to be key to body-brain development and health. Other postings on this site looks at how circadian-redox rhythms are implicated in cell recycling and regeneration (all proliferating cell populations exhibit their own circadian rhythm) and neurogenesis.
Lowered intake of particular nutrients rather than overall calories is also being researched, as is the nutritional modulation of the microbiome. Altered food intake, especially protein and insoluble fiber have a profound effect on the gut microbiota structure, function, and secretion of factors that modulate multiple inflammatory and metabolic pathways. L Fontana 2015.
In a 2014 study, mice were fed a high fat diet. One group ate around the clock, the other group only had access to food in an 8-hour window. Both consumed the same amount of calories overall. But the microbiome of the Time Restricted (TRF) animals looked different to the other group and had more bacterial diversity. The researchers also measured the stool samples of both groups and the mice had more sugar in their stools meaning they had extracted less calories from the food they had eaten than the other group. The authors concluded that: “TRF for 12 hours or shorter offers metabolic benefits irrespective of diet type.” The researchers also measured the stool samples of both groups and the TRF mice had more sugar in their stools meaning they had extracted less calories from the food they had eaten than the other group.
“Studies show that the gut microbiome is highly dynamic, exhibiting daily cyclical fluctuations in composition. Diet-induced obesity dampens the daily feeding/fasting rhythm and diminishes many of these cyclical fluctuations. TRF, in which feeding is consolidated to the nocturnal phase, partially restores these cyclical fluctuations. Furthermore, TRF, which protects against obesity and metabolic diseases, affects bacteria shown to influence host metabolism. Cyclical changes in the gut microbiome from feeding/fasting rhythms contribute to the diversity of gut microflora and likely represent a mechanism by which the gut microbiome affects host metabolism. Thus, feeding pattern and time of harvest, in addition to diet, are important parameters when assessing the microbiome’s contribution to host metabolism”.A Zarrinpar 2014.
A critical role in the clock-nutrition interplay appears to be played by the microbiota. The circadian clock appears to operate as a critical interface between nutrition and homeostasis, calling for more attention on the beneficial effects of chrono-nutrition. G Asher 2015.