Intermittent fasting, or more appropriately time-restricted feeding, has been a topic that has come up frequently in my office. What is time-restricted feeding exactly? It is a regimen that cycles between periods of fasting and periods of normal eating. Periods of fasting can range from 12 hours to 20 hours but, the most widely used is a 16 hr. fast with an 8 hr. eating window.
If you’re considering this approach for yourself, I recommend asking yourself the next question: Why? What benefits from time-restricted feeding am I most impressed with? Benefits that have been attributed to time-restricted feeding include changing, reducing or helping with:
- The function of hormones, cells, and genes
- Weight and visceral fat loss
- Insulin resistance
- Oxidative stress and inflammation
- Cellular repair
What Happens? Physiology during Intermittent Fasting
The reason I mostly recommend intermittent fasting is due to its proposed benefit of causing an immune response which repairs cells and produces positive metabolic changes. These changes have beneficial effects against obesity, type 2 diabetes, cancer, and cardiovascular disease.
How does intermittent fasting do this? Circadian synchronizers. Nutrient signals and meal-timing are circadian synchronizers. Consuming the majority of the day's energy earlier in the day is associated with lower weight and improved health.
Circadian biology - Eating in sync with circadian rhythm optimizes the function of the body and nutrient utilization/fat burning.
Humans are organisms that have evolved to perform activities during the day versus the night. We have endogenous circadian clocks. Our circadian clock ensures physiological processes are performed at optimal times. They regulate eating, sleeping, hormones, physiologic processes, and also coordinate metabolism and energetics.
Our circadian clock is located in the hypothalamus, which is the master clock and is entrained to light and dark stimuli. Feeding is a dominant timing cue. Having proper meal times based on your daily activities (upon waking) will improve your body’s physiology. Discontinuing meal consumption at the right time will allow your body to enter the cleansing and repair phase that it needs daily.
If you have any questions about if and/or how you could implement an intermittent fast, feel free to contact me at
nutrition@houstonian.com.
By: E. Denise Hernandez, MS, RD, LD