“Intermittent fasting (or time-restricted feeding) is a method of limiting the time window you eat each day to a consistent number of hours and a consistent time each day. Between 8-10 hours of (an) eating window is considered optimal in humans, which leaves 14-16 hours for your body to fast. This period allows your organs a break from digesting so they can heal.” -Dr. Satchin Panda
What Is Intermittent Fasting
Intermittent Fasting (IF) is an approach where individuals intentionally limit the time window in which they eat and keep those hours consistent. Done properly research has found many benefits to allowing the body time to rest from digesting food in this way.
Benefits of IF
- Blood Sugar Regulation
- Weight Loss
- Better Sleep
- Reduce Leaky Gut
- More Energy
- Increased Nutrition
- Improvement in Blood Pressure
A Look At The Science
In 2012, a study came out that would expand our knowledge of how our eating patterns affect the body. Until this point most professionals believed that the quality and quantity of food were the main issues surrounding nutrition. This new knowledge would show us that when we eat impacts our health as much as what we eat and how much we eat.
Researchers divided a group of mice with the exact same genes into two groups. Both groups were given the same diet and amount of calories. The only difference between these groups was the timing of when they were fed. The first group could eat the food whenever they wanted while the second group was restricted to eating their food within a consistent 8 hour window of time.
After 18 weeks, they found that “the first group of mice were completely obese,” they had diabetes, cardiovascular disease, and fatty liver disease. However, the group that was restricted to eating within an 8 hour window of time was “completely protected from all of this disease.” These results are amazing especially when you consider that all of the other factors were the same.
Researchers found similar benefits when they looked at the results of intermittent fasting in human studies. One study took a small group of overweight people and asked them to limit their eating window from 14 hours to 10 hours. After 16 weeks they “lost 3 to 4 percent of their body weight” without any other required changes.
The Circadian Rhythm and What Happens In The Human Body
A circadian rhythm is “a natural, internal process that regulates the sleep-wake cycle and repeats roughly every 24 hours.”
Most people recognize that our brain needs a certain amount of sleep each night to function properly, but not many realize that the other organs in our body need this rest as well. According to neuroscientist Joseph Takahashi, “almost every cell in the body contains a circadian clock.” Our pancreas, stomach, and intestines need to ‘sleep’ just like our brain.
As melatonin levels rise later in the day, the pancreas production of insulin slows down. This can result in higher levels of glucose when eating later in the evening and put a strain on the pancreas.
The stomach, on the other hand, produces more acid when we eat at night which can cause acid reflux. In addition, since the digestive tract is slower in the evening the food doesn’t get pumped from the stomach into the intestines which can result in indigestion.
Our intestines need time to repair every night. According to Panda, our bodies have to “replace nearly 8 to 15% of our gut lining (every night), because it gets damaged with the digestive process.” This can not happen while it is busy processing a late dinner, but without time to heal there is a risk of leaky gut which can lead to autoimmune disease, food allergies, etc. Intermittent fasting can provide 12-16 hours of rest for the healing to take place, improving the health of the gut.
How to Begin Intermittent Fasting
If you want to get the health benefits from intermittent fasting you may want to consider following these principles. Please listen to your body (and consult your healthcare provider if you have any health concerns or preexisting conditions. Some people may not be metabolically stable enough to handle this right away.)
- Adopt a 10-hour eating window (or even an 8-hour window).
- Don’t eat for at least 2-3 hours before bed.
- Having an early dinner is more beneficial than having a late breakfast when possible.
- Eating a larger meal in the first half of the eating window is generally better than having a larger meal towards the end of it.
- Try this for 12 weeks and then evaluate your progress.
- If your nutrition has improved you may be able to relax to an 11-hour eating window.
- It is typical to feel hungry at times throughout the first week, but your body should adjust rather quickly.
*These suggestions need to be balanced with the social needs of an individual who may enjoy eating a dinnertime meal with their family or friends. Satchin Panda states, “if someone has a lifestyle where eating dinner with friends or family is the most important thing, and giving up that one takes away all the joy of life, then I think it’s better to skip breakfast and tend to go towards dinner.”
But I Do That Already
Many people assume that they are eating this way when in reality they are not! This is because we often eat without thinking about it. For example, many people grab a small healthy snack late into the night without considering that as part of their eating window.
According to Panda, “we’ve got to remember that whether we eat a big meal or a little apple, our stomach has to process it, (and) send it to the liver. The whole village wakes to process the apple.” He suggests using an app called My Circadian Clock to really get an accurate picture of when we are eating. For more information on your body’s circadian rhythm, check out Panda’s book The Circadian Code: Lose Weight, Supercharge Your Energy, and Transform Your Health from Morning to Midnight.
When I think about our ancestors long ago, it seems reasonable to believe that they ate this way. Before the invention of artificial light and refrigerators people simply did not have access to food around the clock like we do today. When current research affirms the benefit of what our ancestors did, it gets my attention!
Take some time to notice your eating patterns this week. How long is your eating window? Are your organs getting the rest they deserve? You may be surprised by what you find and how a little change can make a big impact on your health.