Our brain has a part called the Hypothalamus. This is light-sensitive and is often referred to as a master clock for the body. It is termed as the Circadian clock which works on a 24-hour cycle coinciding with daylight and darkness. In addition, scientists believe that each cell also has an individual circadian rhythm. This process has an impact on our entire body. The sleep-wake cycle, our metabolism, hormonal activity, nerves, cardiovascular system, our digestion, and most importantly our gut microbiota, are greatly affected when the circadian rhythm is out of sync.
THE SCIENCE OF THE CONCEPT:
The concept of the Circadian diet is based on assumptions made from a number of experimental findings on lab animals. These studies have highlighted the fact that our gut microbes are more active during the day and produce a larger amount of antimicrobial compounds. This is probably because we eat during the day, and the chances of infections are higher. Also, we know for a fact that fat loss is more in early eaters. Human studies in Spain have highlighted the fact that people who have late lunches - post 3 pm, and late dinners - post 9 pm, lose the least amount of weight. People who are working night shifts, eating late are also more prone to the risk of diabetes. Melatonin, a hormone with a central role in the circadian system, increases at night near bedtime, and it is also known to be detrimental to glucose tolerance. So eating late, when melatonin is increasing, equals poor glucose metabolism, which will lead to fat deposition and no weight loss. Sleep disruption also plays havoc with hunger hormones Ghrelin and Leptin, leading to food cravings, especially sugar cravings.
It is basically following an eating pattern where the eating window for the day is 7 am-7 pm. It is a time-restricted feeding (TRF), wherein you are to eat your food within an early span of the day. This is followed by a fasting period of 12 hours, so this may also be similar to intermittent fasting.
The rules are simple:
- Eat early, 7 am-7 pm or latest 8 am-8 pm.
- Breakfast should be the heaviest meal, and dinner the lightest meal.
- Divide the calories into three meals and two snacks.
- Each meal must contain healthy proteins, whole grains, lots of vegetables, and adequate dairy.
- 2-3 fruits per day and a handful of nuts will ensure a diet that brings a lot of protection.
- Weight loss/management with a focus on fat loss. 10-12 hours of no feeding result in the mobilization of fat as the preferred fuel for the body. This leads to lowering adiposity in stored fat, and it is well established that more than overall weight, the fat content of the body is detrimental to the onset of diseases.
- It is shown to have a great positive impact on chronic problems from Rheumatoid Arthritis to Asthma. This is linked to the fact that eating at the right time helps keep the inflammatory process under control and relieves symptoms.
- TRF is also very beneficial for a healthy gut. Recent studies have pointed to an improved biodiversity of gut bacteria in populations that follow time-restricted eating. A healthy gut translates into good immunity, better metabolic balance, and a healthier body.
- TRF is positively correlated with improved sugar control, insulin utilization. Eating at proper timings is also essential along with the overall eating windows.
- Eating at proper timings, getting good sleep at the proper time all work for a healthier, more energetic metabolism and health.
Limitations: Circadian timing for individuals is not the same. The variations of up to 4 hours have been observed because of genetic make-up. It has been seen that as far as weight loss is concerned, about 44% people were successful with this pattern in one study. So we need to sit with an expert and figure out the correct time.
In conclusion I would say that eating at the same time daily, and eating early is the best bet for a healthy life. If you work night shift, you can still follow the principle and keep two healthy snacks for the night and take the same at fixed hours.
About Rupali DattaRupali Datta is a Clinical Nutritionist and has worked in leading corporate hospitals. She has created and lead teams of professionals to deliver clinical solutions for patients across all medical specialties including critical care. She is a member of the Indian Dietetic Association and Indian Association of Parenteral and Enteral Nutrition.