When you eat matters, along with what and how much you eat. Intermittent fasting for weight loss is about setting boundaries around when you eat. That’s it.
I’ll coach you through how to get started today.
Before we dive in, let me provide a brief framework for my perspective as a Registered Dietitian. Intermittent fasting is a contentious topic.
Rightfully so, fasting is not for everyone. That said, for those willing to read the literature, as I have, will find that intermittent fasting could be an influential tool not only for weight loss, but also for longevity.
I do not view intermittent fasting as a diet nor do I believe in rigid food rules. I want you to have the freedom and flexibility of food choice that an eating window provides.
You can love yourself and want to lose weight. There is nothing wrong with that.
I help my clients discover when, how much, and what they should be eating to optimize their health. Intermittent fasting is the most powerful tool I use.
Whew, okay. Now that we’re settled, let’s get started.
Intermittent Fasting Defined
Let’s get clear on what I mean when I say “intermittent fasting” because there are several different approaches.
16:8 intermittent fasting
Most mainstream references to intermittent fasting are talking about 16:8, which includes a 16-hour fasting window and an 8-hour eating window.
There are other types of eating windows such as 14:10 and 13:11 or even 20:4 that are still considered intermittent fasting. In my view, 12:12 is just normal eating, but is a good starting point.
5:2 intermittent fasting
This type of intermittent fasting includes 5 days of typical eating and two days of total fasting or restricting calories to anywhere between 500 and 700 per day. This regimen is also marketed as the The Fast Diet.
Alternate Day Fasting (ADF)
Alternate day fasting, as the name suggests, includes typical eating one day followed by total fasting or significant calorie restriction to 500 and 700 calories the following day.
Are you starting to see why this can be confusing? So many different ways to define intermittent fasting.
There is no one way to go about trying intermittent fasting, just as there is no one diet for every person.
The Type of Intermittent Fasting I Use in Coaching
With my clients, I use a combination of a daily fasting period and eating period. I do not use 5:2 or ADF as I do not think they are sustainable and should really only be used if you are working closely with a physician.
Most of my clients work their way toward a 14:10 or 16:8 regimen that they sustain for long periods of time successfully.
How Does Intermittent Fasting Help with Weight Loss?
Weight loss occurs because of calorie restriction. There are no two ways around that fact.
You can restrict calories by adjusting what and how much you eat. You can also exercise to create a calorie restriction, but it is very challenging to lose weight through exercise alone.
What if instead of restricting calories, we compress them in a smaller eating window?
What the research says about eating windows
Dr. Satchin Panda, a leading researcher on circadian rhythms and time-restricted feeding examined compressing calories with mice. His lab found that the
mice that compressed their calories during the day and ate as much of a high fat diet as they wanted lost more weight than mice that ate a restricted amount of calories but during a longer period of time per day.
These mice ate more of a bad diet, but just in a shorter period of time and lost more weight than the mice that got to eat for as many hours as they wanted.
We are not mice. I know.
On average, when humans restrict their calories to 8- or 10-hour windows, they reduce their daily intake by 200 to 650 calories. Dr. Panda’s ongoing study in humans using MyCircadian Clock app is confirming this hypothesis.
In addition to weight loss, there are incredibly beneficial things that happen inside the body when you fast for at least 12 hours.
The two main highlights are that the body’s blood sugars drop at least 20% and you begin to activate the metabolic pathways that are associated with longevity. Basically your body’s nightly housekeeping for cells.
In case you missed it, I have a summary of these benefits in the first blog post about intermittent fasting and is worth a brief refresher. Zero Fasting also offers a great easy to read summary of what happens in the body when you are fasting.
Find the Intermittent Fasting Regimen for You
The best place to start is to think about what you are currently doing now and what is reasonable for you moving forward.
I’d never have a client start with a 24-hour fast. And still, almost everyone asks me if I’m going to do that. Nope, I want you to be successful, not run for the hills.
When I started experimenting with fasting three years ago, it felt challenging and scary to limit my calories to 11 hours and do a 13-hour overnight fast.
I had to overcome nearly 2 decades of believing that I needed to eat every 2-3 hours and breakfast was the most important meal. I never really stopped to ask when breakfast should happen.
Finding your Eating Window
I start eating every day at _________ am/pm
I finish eating every day at _________ am/pm
My current eating window is ________ hours.
Is that eating window more or less than 11 hours?
Don’t feel bad if it’s more. Before I had kids, I used to do personal training and teach fitness classes at 5:30 in the morning.
I remember I would have a glass of wine after a late dinner and then eat around 4:30 am before class. I had a fasting window of like 8 hours and then ate the whole day every 2 to 3 hours. *gasp*
Set Your Eating Window Goal
Instead of focusing on the fasting hours, I want you to set your eating window for the day. I’ll use myself as an example.
I set a 10-hour eating window each day.
I don’t eat before 8 am or after 6 pm. That works for me because I work from home and I like to be able to eat 3 meals per day.
It’s okay to flex those times from day to day. Remember: no rigid food rules. In fact, some research suggests that you can still get the benefits of intermittent fasting even if you are only able to do 5 days per week.
So many people get hung up on the fasting times. The eating window is more important. Set your eating window and then work fasting around that.
To track my fasting time, I use Zero-Fasting Tracker app. It is a timer and helps me track my fasts so I don’t have to think about it.
What is your eating window? Write it down. Email it to me at [email protected] or send me a message through social media. Put it out into the world and have someone keep you accountable.
What breaks the fast?
This is the most popular question.
Food? Yep. All day. That one was easy.
Does coffee break the fast? Black coffee, no. Coffee with cream, yes (this one actually has a caveat, but we’ll stick with the perspective of weight loss for today) Coffee with cream and sugar, double yes.
Does herbal tea break the fast? If you are going for a pristine fast of complete metabolic and gut rest, then yes it does. All other reasons, no.
Does flavored, sparkling or seltzer water break the fast? If they are calorie-free, yes. Be careful! Many flavored waters are sweetened or contain aspartame.
It’s time to take action.
Step 1. Write down your eating window goal. I am going to start eating at _____ and stop eating at ______ each day.
Step 2. Download the Zero-Fasting Tracker app or another timer so that you don’t have to remember what time you finished eating.
Step 3. Try it tonight.
Let go of the idea that you will be overly hungry. Many of us are scared to feel hungry. I sure was when I started!
It’s okay to feel scared when you try new things.
If it feels too restrictive or you worry you might be too hungry and so you overeat at dinner every night, then intermittent fasting may not work for you.
Guess what? That is perfectly fine. Like I said, fasting isn’t for everyone.
Know this one fact. You can do hard things. I know it. You made it to the bottom of this post, so you’re ready.
Want to dig into the intermittent fasting research?
Here’s what the latest literature says
Intermittent Fasting same as Med diet and Paleo for 12 mo weight loss
Alternate Day Fasting effective for weight loss and NAFLD symptom reduction, but very challenging to adhere to long term.
Intermittent Fasting helps with weight loss without greatly increasing appetite and subsequent food intake, as seen with chronic calorie restriction in women.
Time Restricted Feeding regimens achieved a superior effect in promoting weight-loss and reducing fasting glucose compared to approaches with unrestricted time in meal consumption. However, long-term and well-designed trials are needed to draw definitive conclusions.
From what we know, our best available research suggests that 3 meal-timing habits are likely important for good health.
- a consistent daily eating duration of fewer than 12 h per day,
- eating most calories in the earlier part of the day, and
- avoiding food intake close to bedtime, while sleeping, or very early morning, when melatonin levels are high.