INTERMITTENT FASTING: IS IT THE KEY TO LONGEVITY, HEALTH, AND THE PERFECT BODY?
A quick google search of intermittent fasting leads you to believe it’s the miracle cure for anything and everything. From fat busting potential, to immortality, intermittent fasting has gotten a pretty good response over the last several years. But it’s a tool that (in my humble opinion) isn’t explained very well and isn’t used effectively. Like probiotics, there are specific protocols for specific outcomes and choosing random and restrictive times to eat will probably make you go crazy faster than it will deliver results. So is it really all it’s cracked up to be? Do you need to fast for 12 hours, 16 hours, or one day a week? Let’s define what intermittent fasting really is so that I can teach you how to implement it to benefit you the MOST!
Intermittent fasting has actually been around since, well, FOREVER. Marie Antoinette said “There is nothing new, except what we have forgotten”. Ancient Greeks and every major religion worldwide has practice some for of fasting at one time or another.
It’s kind of funny how most of the current health trends are usually practices that have cycled in and out of popularity isn’t it? (I’m looking at you keto diet) It’s also important to mention that most of the research available on intermittent fasting has been done only in mouse models. This is important from a scientific perspective because even though mouse models can be extremely beneficial in introductory research, mouse metabolism is VERY different from humans and should be interpreted and applied to humans loosely.
ON TO THE NITTY GRITTY:
When we talk about intermittent fasting, we are usually referencing time restricted feeding, which is how you will find it described in scientific literature. No matter what kind of time restricted feeding protocol we are talking about, it all boils down to windows of time without caloric intake, and periods of time with caloric intake. Eating and not eating. BOOM. Sounds pretty simple right? Yes and no. When we dive into the research behind it, there are really four main outcomes, or reasons to fast and different feeding windows depending on what your goal is:
IMPROVED IMMUNE FUNCTION (THINK AUTOIMMUNE CONDITIONS):
Alternate day fasting shows the most improvement in immune response and immune cell activity
METABOLIC IMPROVEMENTS (THINK CARDIOVASCULAR DISEASE RISK INDICATORS):
A modified fast is your best chance for improving those markers of cardiovascular disease risk like blood pressure, LDL, insulin sensitivity, blood glucose, etc)
BODY COMPOSITION / WEIGHT LOSS:
Time restricted feeding shows the most promise for improving body composition or supporting weight loss. This is your typical 16:8 or 12:12 fast you seeing being popularized by the media
LONGEVITY (NOT JUST LIVING LONGER, BUT THRIVING INTO OLD AGE):
Modest calorie restriction (along with a balanced, whole food diet) can improve your chances of living a long and healthy life, but so can any form of fasting.
This all sounds great Ashley, but what if I want all these benefits? Do I just never eat again? Don’t be so dramatic! The good news is that all of these fasts can lead to modest improvements in all the mentioned categories, it’s just that specific fasts show MORE improvement. My suggestion: Prioritize ONE goal and follow that fasting protocol. Here’s how:
ALTERNATE DAY FASTING:
It’s exactly how it sounds. No calories every other day. For example, eat Monday, Wednesday, Friday, Sunday and then Tuesday, Thursday, Saturday, and repeat. This type of fasting has some cool potential, but its not all sunshine and roses. It may also be difficult to follow. I caution using this type of fast if you are prone to over eating, hanger, binge eating, and strong cravings.
POSSIBLE BENEFITS
Improved immune function
Protection against cancer
Decreased cholesterol and triglycerides
Decreased fasting insulin and blood glucose
Weight loss
POSSIBLE SIDE EFFECTS
Increased LDL
Increased inflammation
MODIFIED FAST (5:2)
Fast for two NON-consecutive days every week. What this could look like is fasting on Monday and Friday, Tuesday and Thursday, Sunday and Wednesday. But guess what, the fasting days are not true fasts. 20-25% of normal caloric intake on these fasting days can give you all the metabolic health benefits you’re looking for. Non-fasting days are normal feeding/caloric days. So if you normally eat a 2,000 calorie diet, you would eat 400-500 calories on your fast days, and 2,000 calories on your fed days.
POSSIBLE BENEFITS:
Weight loss over various lengths of time (8 weeks – 6 months)
Decreased fasting insulin but not glucose (ATTN: PCOS peeps, those with insulin resistance and those with elevated androgens)
May be important for hormone regulation (see above)
Decreased lipids (think triglycerides and cholesterol)
Decreased inflammation (yay! this is key factor in obesity, chronic disease, and metabolic derangement)
POSSIBLE SIDE EFFECTS:
None identified at this time
TIME RESTRICTED FEEDING
Ok before we even begin to get into this, let me just say two very important words CIRCADIAN RYTHMN.
Woo ok got that off my chest. This is the most popular type of fasting by far because of its potential for weight loss and body composition improvement. Bonus: benefits are still seen even with calorie maintenance. Often times fasts improve weight loss attempts simply because it leads to less food (calories) being consumed, but by following a shorter feeding window daily and eating your full estimated energy needs, you may still lose weight. Yipee for eating! So what are the key take aways from the research and how should I implement a time restricted feed?
Research supports benefits from any fast greater than 11 hours. 12:12 being the most common in research. So for all of you struggling to maintain a 16:8 window….don’t sweat it! Switch to a 12 hour fast and you will likely continue to see the same if not better results than before
Circadian rhythm is the key player behind why this fast works. Your body’s internal clock operates in conjunction with the sunlight and a typical 12 hour night time window or darkness. So eating within this “night time window” disrupts circadian biology, energy balance, and the microbiome
Circadian rhythm is the key behind intermittent fasting (Ashley Marolo RDN, LDN from Clearcreek Nutrition and Wellness Co.)
POSSIBLE BENEFITS
Weight loss
Better sleep
Decreased cholesterol and triglycerides
Decreased fasting insulin and blood glucose
Decreased inflammation
POSSIBLE SIDE EFFECTS:
None identified at this time
SO NOW WHAT?
WHAT FOODS BREAK A FAST?
Anything with calories
Caffeine
Q: Does this include detox drinks?
A: Are there calories in it? Is there caffeine in it? Yes? Then yes it will break your fast.
Q: What about coffee creamer?
A: Coffee and creamer will both break a fast.
WHAT CAN I HAVE DURING A FASTING WINDOW?
herbal tea (caffeine free)
black decaf coffee
hot water with lemon
YOU’RE READY, YOU’RE MOTIVATED, YOU KNOW WHAT YOUR GOALS ARE AND WHAT FAST IS RIGHT FOR YOU BUT WAIT! STOP AND CONSIDER THESE THINGS BEFORE YOU BEGIN A FAST:
CONSIDERING ALTERNATE DAY OR MODIFIED FASTS:
What did you eat the day before?
What will you eat the day after?
Optimize the fast with health promoting foods
Women should consider challenges to fasting during certain phases of cycle, for example women often experience stronger cravings for carbohydrates and have a higher caloric intake in their luteal phase.
CAN I WORKOUT?
Consider inflammation and adaptation potential
Maintain proper hydration and electrolytes
If you start feeling weak or dizzy STOP
Fasted vs fed exercise
Dependent on you, sport, and goals
WHO SHOULD NOT FAST?
Short answer: anyone with insulin dependent diabetes, fighting infection, critically ill, or recovering from infection or surgery
Longer answer: Under guidance and supervision from a licensed health care practitioner, fasts can be done by anyone and everyone, with special considerations and timing based on your specific medical condition
I have experimented with all of these fasts except alternate day fasting…if you can do that more power too you (you might be super human…or an alien). I regularly practice circadian rhythm feeding and my fasts tend to be 12-14 hours long, but I do this intuitively. I don’t track it, I don’t stop myself from eating if I’m truly hungry. If I wake up hungry, I eat. If I’m saying up late working, I eat. Circadian rhythm feeding and intuitive eating are fluid and flexible which is why I love them. They are really feasible for anyone!
