Intermittent fasting is a hot topic, and one I get lots of questions about. Lots! Everyone seems to have an opinion. What I find more interesting than opinions is what the research says about intermittent fasting, so let’s take a look at IF from that lens.
Did you know that it was in the top 10 diet-related searches on Google in 2018? All this hype might lead you to believe that everyone should be fasting, but the research isn’t quite as clear-cut.
While there is no single definition for IF (also referred to as intermittent energy restriction, or IER), it essentially means restricting caloric intake for a certain period of time.
There are three common ways of fasting:
Time-restricted feeding: Fasting 12 to 21 hours per day and having a specified eating window to consume food without restricting calories
Alternate-day fasting: Going a full day without eating
Modified fasting: Periods of severely limited food intake (5:2= 5 days normal eating, 2 days restricted intake)
Intermittent Fasting and Weight Management
Fasting can be a tool for weight loss but is not necessarily any better than simply reducing caloric intake.
So why do people seem to lose weight with IF?
When it comes to any diet or plan, the reason people lose weight is more about the caloric intake and awareness of food, portions, etc., rather than the specific dietary protocol they follow. This appears to be true for fasting as well. IF may work as a tool, but isn’t superior for weight loss.
Much like moving from body-weight exercises in the gym to performing higher-level body-building movements, there are certain nutritional foundations that should be mastered before manipulating caloric intake with fasting.
For instance, a 2019 study found that people who eat a diet with more highly processed food end up eating approximately 500 more calories per day. The study suggested, “Limiting consumption of ultra-processed foods may be an effective strategy for obesity prevention and treatment” (Hall et al, 2019).
Want to improve weight loss or health? You’ll benefit by eating fewer highly processed foods and eating more fruits and vegetables, before moving to higher-level strategies like fasting.
It’s always about the basics, isn’t it? Keep it simple and keep it basic!
Intermittent Fasting and Managing Cholesterol and Glucose
Researchers have researched using IF to help manage both cholesterol levels and glucose. The results, however, have been less than consistent. If you want to know more about the specific studies, let me know. What’s important to know is that while the research results on IF are mixed, previous studies have shown that the strategies that have the biggest impact on managing cholesterol and glucose/A1c are increasing fiber intake with fruits, vegetables and whole grains in addition to increasing exercise.
Practical Concerns of Following an Intermittent Fasting Diet
Supporters of IF say that fasting is simple because tracking calories or eating specific food isn’t necessary. Simply eat only during your specific days or eating times and you’ll lose weight. However, as research suggests, implementation isn’t quite so simple.
The prospect of going without food for a whole day or sticking to a very low-calorie intake a few days a week may not be feasible in the long-term. Putting fasting into practice in daily life becomes more complicated due to social events, cravings, or high stress levels. Despite the best of intentions, daily life often gets in the way of being able to maintain an IF diet.
Is Intermittent Fasting Appropriate for Everyone?
While there is no specific research on IF and female hormones, there are some studies that suggest fasting could adversely impact ovulation and fertility in women. For example, Fujiwara and Nakata (2010) found that skipping breakfast was related to menstruation disorders in college women. In subsequent research, Fujiwara and colleagues (2018) found evidence that fasting negatively impacted ovulation in female rats. While animal data cannot directly be applied to humans, it does suggest that further research is necessary, especially considering the impact fasting can have on hormonal health.
There are a few groups of people who should NOT fast.
- Pregnant or breastfeeding women
- Anyone with an unhealthy relationship with food, or a history of eating disorders or disordered eating habits
- Anyone with diabetes, or who experiences low blood sugar
Additionally, women with a history of irregular periods or who are trying to conceive are urged to proceed with caution, as IF may adversely impact hormone levels.
Here’s What The Research Tells Me: More Research is Needed
A lack of high-quality, large-scale controlled studies and longitudinal data, as well as multiple definitions and methods for fasting, make it challenging to draw recommendations from the current research. Without long-term research studies, including studies that specifically investigate the impact of IF on men and women, it’s too early to know the long-term benefits or drawbacks of fasting.
In their comprehensive research review of animal and human studies on fasting, Harvie and Howell (2017) sum up what we can safely conclude about IR: “We do not know conclusively whether long-term IER [intermittent energy restriction] is a safe and effective method of weight control for subjects who are overweight or obese or whether IER may confer health benefits to people of any weight independent of weight loss. High-quality research comparing long-term outcomes of IER and CER [continuous energy restriction] are required to ascertain any true benefits or detrimental effects which IER may have for controlling weight and improving metabolic health in the population.”
You will of course draw your own conclusions perhaps, based on your own trials. However, I want to remind you about the basic tenets of a healthy diet, such as consuming a variety of whole, fresh foods, practicing portion control and reducing saturated fats and processed foods. Using this as your guide for food choices improves your overall health and well-being over the long-term. And the long term is what counts!
Let’s Talk Nutrition Beyond Intermittent Fasting
It starts with social media. Maybe it’s Facebook or Instagram.
Someone with abundant personality, a great body and a smooth sales pitch talks
about the details for their nutrition plan which they BELIEVE is the
best way to eat……for everyone and forever.
It often starts with Google, when a simple search for “what’s good nutrition”
gives you 118 million things to read. (And each website has a unique
story to tell about what they BELIEVE is the best way to eat.)
Some of these beliefs might be:
* “I believe that sugar is poison.”
* “I don’t believe humans were meant to eat grains.”
* “I believe in only eating organic food.”
Please understand: There’s nothing wrong with wanting to believe these things.
Rules can be a huge relief because nutrition can be confusing and we easily slip into overwhelm.
However, this becomes problematic when emotional bias or certain philosophies create our health decisions. We can’t ignore what science has to say about the facts, or perhaps such facts don’t even exist. Why? Because, just like chemistry and physics, nutrition is a SCIENCE; it follows certain principles.
When you understand these principles, it’s easier to make smarter
decisions on what to eat, when to eat, how to eat — and how to use
nutrition to look, feel, and move better.
I don’t believe in a one-size-fits-all nutritional system. And neither should you.
Can you start putting the biased beliefs away and choose instead to embrace learning,
critical thinking, and evidence-based analysis to every eating decision you make?
Need help navigating your nutritional terrain? Start here!
A huge thanks to everyone who sends me feedback about the monthly Joyinmovement newsletters. I always appreciate questions, too. The feedback and questions help shape my future newsletters as well as create next-step plans for Joyinmovement. So keep your feedback coming.
I’ve been very glad to hear readers are getting as much value out of reading them as I am writing them. As you know, I personally answer each and every email 🙂
Interested in traveling more for less? Here’s where to start. Make sure to check out my hotel reviews before you choose your hotel. And if you’re a coffee drinker, here’s where to find the best coffee in cities around the world.
This month has me at home digging in to work projects. My travel brain gave over to my work brain. Although I do work when I travel, I’ll admit to being way more work oriented and getting a whole lot more done when I’m home and can dig in and focus. My travel brain is patient and knows it will get a chance to surface before too long 🙂
I did get to the beach last week and saw the most brilliant sunset I’ve ever seen. Absolutely stunning. There’s just something special about the ocean air, the sound of waves, and the smell of all those California sea lions that’s simply inspiring. Well the smell of the sea lion pups isn’t all the inspiring, but you know what I mean! If you haven’t been to the ocean in a while, take your Joyinmovement to the sea!
I’ve been hiking the local trails and am working on upper body strength training with a pushup routine. It’s not easy, but essential, so I’m sticking with it.
Are you making changes that focus on your health and fitness? What are you doing these days to keep your muscle mass from decreasing? Big plans (or small but meaningful plans) for 2020 travels? Drop me a line and tell me about it.
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