“The best of all medicines are resting and fasting.”–Benjamin Franklin
Fasting has been a part of human culture for our entire existence. Periods of famine, religious practice, and self-imposed periods without food for physical and spiritual gains are some of the most common reasons for fasting. In fact, we practice fasting every night through sleep. Prolonging this time of fasting around sleep, even by a little bit, can help greatly in your pursuit of personal fitness supremacy.
Intermittent fasting (IF) has enjoyed a lot of attention in the health and fitness space in recent years, often being touted as the answer to appetite management and blood sugar control, body composition and weight management, a better connection to hunger and lifestyle habits, and longevity and disease prevention.
What is Intermittent Fasting?
Put simply, IF is alternating periods of eating and not eating. As mentioned before, we do this naturally through sleep. In fact, it’s common for most people to go for about twelve hours per day without food, assuming eight hours of sleep with a couple of hours of buffer on either end. Medically speaking, a person is considered to be fasting if they go 8-12 hours without food.
IF can come in many forms: a daily time-restricted eating window (usually shorter than 12 hours), picking a day or two during the week to completely abstain from food, or some combination of the two. Diet programs, like Eat Stop Eat, The Warrior Diet, and Fast 5 are some of the more popular methods of IF. There are dozens of roads that lead to Rome, but the success of an IF program will always depend on what an individual can realistically, consistently handle.
4 Potential Benefits of IF:
Body Composition and Weight Management
Outside of religious practice, one could argue that most people practice IF to manage body composition and weight. In theory, the shortened window of eating time, combined with nutrient-dense, whole foods, limits the number of calories a person can and will eat during the day.
For this to work, you need some sort of plan once you break your fast. Prioritizing protein, a variety of vegetables and fruits, healthy fats, adequate starches to support your daily activity, and deciding how many meals you want to eat each day will contribute greatly to a successful IF plan. Please, do not get seduced by the Internet fasting gurus who claim that you can house an extra-large pizza and cookies every day because you’re fasting most of the day. It sounds ridiculous, but those folks are out there.
For some quick help on a starting point with how many meals, calories, and putting all of it together, this free calculator from Precision Nutrition is hard to beat.
Appetite and Blood Sugar Control
In a 2018 study conducted by the University of Alabama, a small group of obese, pre-diabetic men were placed in two groups:
- Early Time-Restricted Feeding: These men ate their meals between the hours of 8:00 AM and 2:00 PM, which gave them a 6:18 hour feeding to fasting ratio.
- Twelve Hour: These men ate their meals between the hours of 8:00 AM and 8:00 PM, which more closely resembled a typical, non-restrictive feeding window.
After five weeks, neither group lost any significant weight. However, the Early Time-Restricted Feeding group showed significantly lowered blood pressure, significantly lowered insulin levels, and increased insulin sensitivity. They also reported an overall decrease in appetite. A relatively simple tweak in feeding time ended-up improving the metabolic functions of these men, even though they didn’t lose any weight.
What does this have to do with active, healthy athletes and individuals? That remains to be seen. Most studies on fasting are done on animals, individuals (primarily men) with some sort of metabolic disease, or religious groups.
However, the mechanisms involved with helping the men described above can possibly help an otherwise healthy individual stay that way by keeping appetite and insulin levels regulated, which will likely contribute to a future with a smooth-running metabolism and healthy body weight.
Longevity and Disease Prevention
At the time of this writing, aging, and eventually death, are inevitable parts of being a human. Yeah, it’s a bummer…keep living. Pretty much everything we do, from exercising to eating has a metabolic cost and causes cellular damage that must be repaired. As we age, repair at the cellular level becomes harder and harder for the body to complete successfully, and one day it finally stops.
However, this article from the New England Journal of Medicine states that through the fasting process, our cells activate pathways that defend against oxidative and metabolic stress, as well as remove or repair damaged molecules. Once we feed again, cells regrow and are a bit more robust.
Fasting effectively gives our cells a chance to clean-up waste products, so we don’t have a bunch of junk floating around, which can cause undue systemic inflammation and possibly lead to chronic disease. However, it’s typical that people eat three meals per day plus snacks, so there’s no fasting to be had.
For this process to work effectively, the body needs time to expend the energy from the last consumed meal and start relying on stored energy, which can take anywhere from 12-16 hours. Of course, that is completely dependent on the individual.
Connection with Hunger Signals and Lifestyle Habits
This is more anecdotal than the other benefit areas, but those who are highly successful with IF share a few qualities:
- They can recognize hunger and know it isn’t an emergency
- They have a plan built around their feeding window and meals
- They have a solid base build on sleep, some nutrition practice, stress management, and movement
Hunger is a big part of fasting, and it’s a big contributor to people not following through with a fasting protocol. Noticing hunger signals, and recognizing whether they are, in fact, signals of hunger and not boredom or thirst is a skill that takes time to build. A gentle feeding restriction can help build this awareness, but one has to be okay with being uncomfortable for a short period of time. Over time, the initial hunger pangs will subside, and your body will adjust to whatever feeding schedule you choose.
As the old saying goes, “Failing to plan is planning to fail”. It’s really hard to be successful in IF without a plan of how long your feeding window will be, how many meals you’ll eat each day, and whether or not you’ll snack in-between your meals. There are a ton of proven methods out there, but you ultimately need to decide what you can realistically, consistently do.
The stronger your nutrition and lifestyle base, the more likely you’ll be successful in achieving any of your nutritional goals. IF is no different. Take your time getting sleep, sound nutritional practices, stress management, and a movement practice dialed-in first. Realistically, that is all most people will ever need. However, if you have those pillars built, trying some form of IF might get you a bit closer to your physical or spiritual goals.
Is IF for Everyone?
The short answer: No. The truth is, IF is not for everybody, and most of the clinical research has been done on specific populations of men, lab animals, and religious groups.
We do know that IF and similar restrictive eating methods are not suitable for:
- Pregnant Women
- Chronically Stressed Individuals
- People with disordered eating
- People with disordered sleeping patterns
- Newcomers to diet and exercise
Is IF Necessary for a Healthy Lifestyle?
Again, no. As with any method of eating with a rigid structure, some people will thrive, and some will not. You can build yourself a healthy lifestyle framework that allows you to thrive without ever fasting or skipping a meal.
To summarize some of the practices I’ve suggested in the past, you really can’t go wrong with:
- Eat a diet that prioritizes variety in protein, vegetables, fruits, healthy fats, and enough starch to help support your physical activity.
- Move every single day and follow a progressive exercise program that challenges you, and most importantly, you enjoy.
- Prioritize sleep: Aim for 7-9 hours in bed, in a cool, dark room, with no electronic distractions.
- Have a strategy for stress management like practicing a hobby, meditating, journaling, praying, etc.
Finally, if you do decide to try IF, read Precision Nutrition’s Experiments with Intermittent Fasting. It does a great job of describing just about everything you would ever want to know about IF and does so with practical examples of common methods. Happy fasting!