When it comes to losing weight, many people want to know what the best diet is. However, increasing research shows that when you eat may just be as important for your health and weight as what you eat. The importance of when we eat is tied to our internal 24-hour biological timing system, called the circadian system.
Circadian rhythms are run by a master clock in the brain and other clocks throughout the body. These rhythms help regulate sleep-wake cycles, hormones, and metabolic processes. While light and dark are the main cues for the clock in the brain, eating is a major cue for clocks in other body tissues. (https://www.aicr.org/).
In the circadian Rhythm diet, you eat during a 12-hour window — typically between 7 a.m. and 7 p.m. — and fast during the other 12 hours. Meal sizes are flipped, with breakfast the largest meal of the day and dinner the smallest. This schedule suggests eating when it makes the most sense, given the daily waxing and waning of various hormones like cortisol, insulin, and leptin. ‘It is now becoming clear that circadian disruption is increasing the incidence and severity of many diseases, including cardiovascular disease and type 2 diabetes.’ (https://www.dailymail.co.uk/)
Factors That Can Change Circadian Rhythm
For some it is a challenge to follow a circadian rhythm diet, and your lifestyle needs and internal clock clash. This can occur because of:
- overnight or off-hours work shifts that go against the natural light and dark times of day
- work shifts with erratic hours
- travel that spans the course of one or more different time zones
- a lifestyle that encourages late-night hours or early wake times
- Medications
- Stress
- mental health conditions like brain damage, dementia, head injuries, or blindness
- poor sleep habits — not having a regular sleep schedule, eating or drinking late at night.
How the Circadian Rhythm Diet Works
Research suggests that practicing circadian rhythm fasting may promote weight loss in multiple ways:
- Reduced calorie intake: Even though people engaging in circadian rhythm fasting can eat as much food as they would like, they often consume fewer calories. It was found that people who stuck with a time-restricted eating plan unintentionally ate 20% fewer calories than they usually would have.
- Reduced appetite: People who are overweight or obese experience a reduction in appetite when practicing early time-restricted eating. This appetite reduction could be due to synchronizing eating with certain hormones released by the body.
- Improved metabolism: By aligning meal times with one’s circadian rhythm, a person can optimize their metabolism. Meals are consumed at times when hormones related to eating, like ghrelin and adiponectin, are at their peaks. These strategic meal times mean the food will be digested and metabolized more efficiently and less likely to be stored as fat tissue.
In a healthy person, levels of cortisol (the stress hormone) peak at around 8 am, giving us a rush of energy to wake us up (in theory). Those levels drop to their lowest at 3 am the next day, before rising back to their peak five hours later at 8 am again. Ideally, this 8 am peak will be triggered by exposure to sunlight, if not an alarm. When it does, the adrenal glands and brain will start pumping adrenalin.
By mid-morning, the cortisol levels start dropping, while the adrenalin (for energy) and serotonin (a mood stabilizer) keep pumping. At midday, metabolism and core body temperature ramp up, getting us hungry and ready to eat.
Risks
This eating style might not be the best choice for everyone, including:
- Older adults with declining metabolism
- People who are underweight or have a lower average weight
- People who have experienced an eating disorder
See a doctor if you experience prolonged difficulties in realigning with your circadian rhythm.
For more: https://www.dailymail.co.uk/