As obesity rates increase, manufacturers develop new ways to ply consumers determined to lose weight or otherwise improve their health with new diets, supplements, and quick-fix solutions that promise fast fat loss “now.” Is Intermittent Fasting the real deal, or just the most popular trend?
Looking for a Fat-Loss “Fix”
Tempting though most can be, ultimately they become disappointing. Beyond not delivering their hyperbolic claims, many of the weight-loss theories so prevalent – you know, stuff like diligent calorie counting, grazing throughout the day, taking some “miracle” supplement Dr. Oz promoted to lose weight, and breakfast being the most important meal – just keep us fatter.
In my own practice, I’ve watched numerous patients struggle with weight, frustratingly transitioning from one diet to another and eventually regaining that weight. Based on empirical evidence and research, I’ve found a solution for many of these patients.
What is Intermittent Fasting?
Intermittent Fasting challenges conventional health theories. Many intermittent fasting practitioners skip breakfast, don’t count calories (or anything for that matter), and go long hours – sometimes days – without eating. With intermittent fasting, when you eat may be just as important as what you eat.
I will never forget the first time I heard of the concept of compressing all meals into a short period of the day. “The Warrior Diet” some would call it.
Mention these concepts to a friend or family member unfamiliar with intermittent fasting and they’ll probably gasp in horror (“But isn’t it unhealthy to skip breakfast!?”). Recently, I mentioned to a professional colleague that I personally consume 2 meals per day. The colleague instantly responded that I should not just be eating 3 meals per day, but more like 4 meals per day “to keep my metabolism up.” However, copious science proves this way of eating safe, effective, and might be the needle mover to reach your goals if past diets or other health measures have yielded less-than-stellar results.
A randomized crossover study found eating two larger meals a day more effective than six smaller meals for people with Type 2 diabetes.(1) That makes sense considering unlike modern-day humans, our Paleolithic ancestors didn’t eat regularly because food remained scarce and when it became available, they devoured it. Obviously, they didn’t have today’s ubiquitous 24-hour restaurants and snack machines.
Is Intermittent Fasting a Fad?
Even though the concept theoretically goes back thousands of years, could intermittent fasting just be another fad diet? That’s what researchers in one review considered. They concluded while no one-size-fits-all solution exists, intermittent fasting presents a healthy, legitimate option for fat loss and optimal health.(2) Let’s briefly look at a few of the benefits of intermittent fasting.
- Chronic disease. Studies show intermittent fasting can reduce your risk for Type 2 diabetes and numerous other diseases.(3) When you’re not gorging all day on high-sugar foods, you stabilize blood sugar and insulin levels, preventing the spikes and crashes that leave you feeling moody, lethargic, and that set the stage for diabetes, cardiovascular disease, and numerous other issues.
- Chronic inflammation underlies nearly every disease, keeping us fat and sick. Plenty of wild-caught fish, plant foods, and supplements like fish oil and curcumin can help reduce inflammation. So can intermittent fasting. One review looked at guided fasting regimens that restricted eating times and quantities over seven-to-21 day periods. Researchers concluded fasting is “associated with deceleration or prevention of most chronic degenerative and chronic inflammatory diseases.”(4)
- Cognitive function. One study that examined obese mice and mice doing intermittent fasting found while obese mice performed OK with cognitive and learning abilities, but felt sluggish and less prone to exercise compared with the control group. The intermittent fasting mice displayed more physical activity and better learning and memory capabilities than the control group. (4)
- Studies show intermittent fasting can strengthen your immune system by limiting inflammation, reducing free radical-induced oxidative stress, and improving immune cells.(3) Translations: Fewer colds and sickness.
- Lipid profile. Over 10 weeks, University of Illinois researchers monitored adults who first did a control diet and then alternate-day intermittent fasting. Participants lost weight, optimized lipid markers like cholesterol and triglycerides, and normalized blood pressure.(5)
- Food intolerances. Constant grazing takes a toll on your digestive tract, and gluten, dairy, and other food intolerances contribute to leaky gut and numerous other gut issues. Intermittent fasting gives your overworked gut a major break. (Obviously, you still want to eliminate food intolerances to get those benefits.)
- Weight loss. While these and other benefits are enticing, let’s be honest. You’re most likely considering intermittent fasting to get into your skinny jeans and nudge the scales in your favor. Good news: intermittent fasting can be an ideal way to lose weight and keep it off.(2)
Why is Intermittent Fasting Optimal for Fat Loss?
Many forward-thinking practitioners agree that while calories count, where those calories come from count way more because they influence fat-regulating hormones.
Interestingly, most intermittent fasting studies don’t restrict calories, so how can it help you lose weight?
For one, as you fast your body eventually shifts from glucose to ketones as its primary fuel. In other words, your body literally burns fat for energy, especially if you’re not gorging on sugary, processed foods when you eat and focus on healthy fats, protein, and lots of high-fiber plant foods that optimize your hormones.
Intermittent fasting further improves these fat-regulating hormones, including:
- Insulin: Insulin is a storage hormone. When it stays elevated beyond its prime, it stores fat really well. A lower-sugar diet combined with intermittent fasting works beautifully to normalize insulin. One study found alternate-day fasting (ADF) improved insulin sensitivity to increase fat burning.(6)
- Norepinephrine: Adrenals-secreted norepinephrine turns up things like arousal, alertness, and attention. It shouldn’t always be “on,” but in the case of fasting, it can benefit you. One study found fast-induced increased norepinephrine lowers glucose and boosts your metabolism. (7) (Participants got those benefits fasting one to four days.)
- Growth hormone (GH): This hormone’s benefits include fat burning and muscle building. Growing older decreases GH,(8) but intermittent fasting can work in your favor here. Researchers found two days of fasting increased GH five-fold.(9)
- Ghrelin: This stomach-secreted hunger hormone cranks up your appetite and tells your brain to eat: (10) Not necessarily good if you’re trying to lose weight, but remember no hormone is entirely good or bad. Ghrelin can also increase GH release,(11) which is definitely a good thing.
- Cortisol: Your primary stress hormone protects you in the short run (it certainly saved our Paleolithic ancestors from hungry saber-tooth tigers), but cortisol should do its job and chill out. One study found folks who did intermittent fasting had decreased cortisol levels,(12) yet too much fasting (over 24 hours at a time, especially if you’re a novice) could potentially stress your adrenals. (More on that in a minute.)
How to Get Started with Intermittent Fasting
Google “intermittent fasting” and you’ll discover numerous plans, from 16-hour daily fasts to once-or-twice weekly 24-hour or longer plans. You’ll probably spend hours reading about plans and get overwhelmed because no hard-and-fast rule to do intermittent fasting exist.
“One approach does not fit all in the quest to achieve body weight control, but this could be a dietary strategy for consideration,” writes Alexandra Johnson, discussing how intermittent fasting potentially benefits weight loss.(2)
Based on several rodent studies, a baseline fast would be about 16 hours. One study showed mice that fasted 16 hours daily had improved insulin sensitivity.(13) Another found mice that ate during an eight-hour period became healthier than mice that eat freely throughout the day, regardless of how much or what they ate during those eight hours.(14)
Especially if you’re a novice, I recommend aiming towards a 16-hour fast. If that initially feels impossible, put your foot in the pool without diving headfirst by having a substantial dinner, closing up the kitchen for the evening, and then prolonging the following morning’s breakfast.
So let’s say you finish eating at 6 p.m. and then have breakfast at 9 a.m. You’ve almost effortlessly created a 15-hour fasting window, and you’ll be sleeping though part of it. Check out more tips on my Guide to Intermittent Fasting on DrHardick.com. If you are female, I do recommend some modifications in my Intermittent Fasting Guide for Men and Women. Check it out.
Simple Hacks to Make it Happen
None of this means it will be smooth sailing in the beginning. With my patients, I’ve found these 10 strategies can make fasting easier and yield better results.
- Focus on healthy foods during your feeding period. Fasting for 16 hours does not mean you get to then consequence-free nosedive into a bacon cheeseburger with fries and a chocolate malt. (Sorry.) You want to create steady, sustained energy and balance fat-regulating hormones during your feeding hours with lean protein, healthy fats, tons of veggies, and lower-glycemic starches.
- Remember fasting means zero Innocuous though it might sound, having a handful of almonds during your fasting hours won’t necessarily undo your hard work, but fasting means no – or as many to zero as possible – calories. Be scrupulous about sneaky calories from things like cream or sugar in your coffee or tea that hijack your progress.
- Remind yourself that hunger will pass. “Hangry” is a popular term these days, and doing intermittent fasting might feed into that less-than-pleasant state of mind. “I thought hunger was making me cranky and irritable,” a patient once told me, “but I eventually learned the illusion of hunger and the ‘I should be eating!’ mentality were what really made me miserable.” Hunger is like an emotion: It will pass, and as your body will become more resilient at handling it over time. Be patient with yourself but stick with the plan.
- Keep it consistent. Patients who stick with a regular eating schedule find compliance becomes easier. You might start eating with a 10 a.m. breakfast and end your day’s eating with a 5 p.m. dinner. Of course, you’ll have exceptions – say, that later-night holiday party – but sticking with a regular eating time schedule makes intermittent fasting more pleasant.
- Drink up. Calorie-free beverages during your fasting hours can do wonders to curb your appetite. One systematic review found drinking water could reduce caloric intake and help you lose more weight. (15) Studies also show green tea can decrease hunger and increase fat burning.(16) Even black coffee can curb hunger, but be careful not to over-caffeinate.
- Distract yourself. Go for a walk or lose yourself in your work during your fasting hours. You’ll encounter times where your brain only wants to focus on food, but you can quickly distract those thoughts by doing something else. Many patients tell me working out becomes optimal during fasting hours.
- Get great sleep. Studies show even a single night of bad sleep makes you hungrier(17) and knock fat-regulating hormones like insulin out of whack.(18) That aftermath doesn’t play out well with intermittent fasting, where momentarily lapses in judgment mean you’re hungrier and more tempted with whatever sugary concoction your coworker’s eating.
- Control stress. Stress can dial up hunger(19), and combined with terrible sleep it can make intermittent fasting seem nearly impossible to maintain. If possible, save your most stressful tasks during your eating hours, when you’re less likely to get cranky and sidetracked when frustrations arise.
- Eat enough. Your body still requires needs nutrient-dense foods, even if you’ve condensed when you eat them. If you’re eating one or two meals in your fasting window, make sure to get your full day’s calories and nutrients. Otherwise, you might get hungry during your fasting hours, derailing your hard work.
- Mix it up. Everyone hits plateaus, and if you find your intermittent fasting plan eventually hits a roadblock, deviate for a few days. You might go back to your regular eating plan or try a once-weekly 24-hour fast, then return to your regular 16-hour daily fast. Remember there are no hard-and-fast rules here; be your own guinea pig and if something isn’t working, don’t be afraid to switch it up.
Caveats about Intermittent Fasting
No one way of eating works for everyone, and that becomes especially true with intermittent fasting.
Don’t shoot the messenger, but men seem to do better with intermittent fasting than women, and this was the inspiration for my Intermittent Fasting Guide for Men vs. Women. That said, some women do tremendously well on an intermittent fasting plan, and I would’t want anyone to count themselves out before trying.
As I mentioned before, prolonged fasting can increase cortisol levels, and for some people that can create more harm than benefits.(20) Among those people include pregnant women, people don’t have a gall bladder, if you have thyroid or adrenal problems, if you’re sick, and if you have anorexia or any kind of eating disorder.
Likewise, potential signs intermittent fasting might be a problem include trouble sleeping, hair loss, low daytime energy, menstrual irregularity, irritability, extreme weight loss, unexplained weight gain, prolonged lightheadedness, and dizziness.
If you’re fasting and feel like you’re going to pass out, please eat something. Erring on the side of caution as you learn how your body reacts to this way of eating will preserve your health and sanity.
Finding a qualified nutritionist who works with intermittent fasting might also benefit you long-term. They can suggest other strategies to overcome hunger and other intermittent fasting glitches and pinpoint why you might eventually be hitting plateaus.
I would recommend talking to your doctor with particular concerns, although most conventional physicians aren’t familiar with intermittent fasting and might not understand its potential benefits.
If you’ve ever done intermittent fasting, what did you find most challenging? Did you get the results you wanted? If you’re female, did you find it harder to maintain than guys you know who’ve done intermittent fasting? Share your thoughts below or on my Facebook page.