I have been reading about the benefits of restricting your daily food intake to an 8-12 hour window and thought I’d share the gist of it in this blog. I know Stu has blogged about this before, so hopefully my points tally up with his.
In essence, it’s about timing your food intake to match your circadian rhythm, which is driven by the daily planetary cycle of 24 hours. Getting out of sync with our biological clocks and rhythms risks a rise in obesity, diabetes, heart disease and cancer. Apparently, chaotic eating, relentless stress, continuous screen gazing, sleep deprivation and a sedentary lifestyle disrupt our powerful circadian rhythm, wreaking havoc on our mental and physical health.
There is a belief that the rise of eating later at night may have thrown off the circadian rhythm that evolved in humans, possibly contributing to rises in obesity. Recent studies in animals and humans are finding that restricting eating to daylight hours can improve health and prevent disease. Clearly seasons will mean less daylight hours in the winter, but the main principle of having at least 12 hours of non-feeding time is the important factor in positive benefits to health.
It is best to consume a balance of whole foods with high quality protein, fat and carbohydrate, and this combined with reducing your feeding window to 8-12 hours is the key to encouraging optimal metabolic processes that lead to enhanced health. It seems that carbohydrates are best metabolised in the morning and early afternoon, based on insulin levels and sensitivity. Cholesterol is broken down in the body most effectively upon awakening. Once daylight fades into night time and feeding ends, the body relies less on glucose and more on fat, as the night moves on. During this phase the body restores and regenerates itself, peaking at about 12 hours of non-feeding time. Cells recycle themselves to promote optimal health and prevent disease and the negative consequences of ageing. Non-feeding time also reduces excess body fat while lowering insulin levels and blood sugar, protects against stroke and slows cognitive decline. Wow, there’s a lot going on in our sleep.
Reducing the feeding window to ten hours in one study produced significant positive results after 16 weeks, such as losing 4% of bodyweight, improved energy levels and more satisfying sleep, while eating normal foods and not adjusting exercise habits.
Eating in sync with the light/dark circadian rhythm and regenerating during a non-feeding period of 12-16 hours may be a realistic target for those who wish to become more healthy, and have struggled with sustaining a restrictive diet.