Intermittent fasting is going viral in the health and wellness industry! Celebrities swear by it. Influencers rave about it. But is it worth all the hype? You may have heard about FWTFL, aka Faster Way To Fat Loss, a program built on the foundation of intermittent fasting. It’s one of many programs being promoted on social media that focuses on the timing of when you eat. So let’s get a good foundation on intermittent fasting and what science has to say about it. Is intermittent fasting FACT or FICTION?
What is “Intermittent Fasting”?
Intermittent fasting (IF) is based on the principle of metabolic switching. By choosing regimented periods to eat and fast, your body exhausts its carb stores and taps into fat storage for energy. By increasing or prolonging the time frame between meals, you are essentially allowing your body to burn through your previous meal and make use of your fat storage more readily.
The Science of IF
When we eat, our food gets broken down by enzymes in the gut, which end up as molecules in our bloodstream. Carbs, particularly sugars and refined grains, get broken down quickly into sugar, which our cells use for energy. If our cells don’t use all the energy created, we store it in our cells as fat. BUT sugar can only enter our cells with insulin, a peptide hormone produced by beta cells in the pancreas. Insulin brings sugar into the fat cells and stores it there. Between meals (if we aren’t snacking), our insulin levels will decrease allowing fat cells to release stored sugar to be used as energy. We are more readily able to lose weight if we let our insulin levels go down. By cyclically allowing your insulin levels to decrease, you are allowing more of your fat storage to be used for energy.
What Research Has Shown
Study #1: The University of Alabama conducted a study with a small group of obese men with pre-diabetes. They compared a form of intermittent fasting called “early time-restricted feeding,” where all meals were fit into an early eight-hour period of the day (7 am to 3 pm),or spread out over 12 hours (between 7 am and 7 pm). Both groups maintained their weight (did not gain or lose) but after five weeks, the eight-hours group had dramatically lower insulin levels and significantly improved insulin sensitivity, as well as significantly lower blood pressure. AND the eight-hours group had significantly decreased appetite.
Study #2: An in-depth review of the science of IF published in the New England Journal of Medicine showed that IF triggers several essential cellular functions. Surprisingly, it has more benefits than improved weight loss. The researchers looked at dozens of animal & human studies to explain how simple fasting (not necessarily IF) improves metabolism, lowers blood sugar; decreases inflammation, which improves a range of health issues from arthritis to asthma; and even helps remove toxins and damaged cells, which lowers ones risk for cancer and enhances brain function.
Study #3: In a study performed in 2015, intermittent fasting was shown to enhance parasympathetic activity mediated by the neurotransmitter, acetylcholine. This allows your “rest and digest” system to work more effectively. So the autonomic neurons that innervate the gut, heart, and arteries are triggered to increase gut motility and decrease heart rate and blood pressure. Which allows for more optimal brain function and peripheral energy metabolism.
Types of Intermittent Fasting
The most common form of IF. Fast for 16 hours/day (ex: 6p-10a or 8p-12a) and eat the remaining 8 hours of the day. Because of it’s simplicity and consistency, it may be one of the easiest to maintain for longevity
Balanced meals 5 days/week and the other 2 days limit intake to one 500-600 calorie meal/day. Can be useful for people who do shift work. Made popular by Kate Harrison’s book “The 5:2 Diet,” which details her experience incorporating IF into her lifestyle routine.
24-hour fasting periods 1-2x/week, aka sundown to sundown. Most common in religious fasting.
What are you allowed to consume when fasting?
Water or other zero-calorie beverages (black coffee or tea).
What diet should I follow when not fasting?
Most nutritionists suggest a well-balanced diet, like the Mediterranean diet. If you’re unfamiliar with the Mediterranean diet, basically it’s rich in complex, unrefined carbohydrates, leafy greens, healthy fats and lean protein. When you’re outside of your fasting period, try not binge or go crazy! Attempt to eat a variety of whole foods that are colorful and not processed. That should always be the goal whether you’re doing the Mediterranean diet or not!
Benefits of IF
Activates parasympathetic nervous system
Lowers blood pressure
Initiates new cell turnover
Increases cognitive function
Promotes healthy weight loss and weight management
Resets hunger hormones
Re-establishes personal self-control
The Obesity Code || The Fast 800
The 5:2 Diet || Fast. Feast. Repeat.
Eat. Feast. Repeat. || The End of Alzheimer’s
Life in the Fasting Lane || The Longevity Diet
Safety and Side Effects
Talk with your doctor before initiating any type of fasting routine. IF may not be beneficial for you if you’re pregnant/breastfeeding, trying to conceive, have a history of amenorrhea (lack of period), have a history of an eating disorder, are underweight, diabetic, or take prescribed medications. ALWAYS consult with your doctor before starting any kind of lifestyle/diet change.
Now you all are probably wondering if I’ve ever tried intermittent fasting. The answer is NO or at least not for an extended period of time. With my work schedule, it’s sometimes hard for me to stick to a true IF plan. But I’m hoping to try and incorporate the 5:2 plan into my week because it seems the most manageable for my schedule. Sometimes you gotta do your research before you commit to something like this, and that’s where I’m at right now!