Intermittent Fasting

Caloric restriction (or fasting) is an age old tradition and cited by researchers as a robust means of increasing health and longevity across the lifespan. Research suggests intermittent fasting (IF) – or fasting for short periods of time (e.g., 16 hours per day) several days per week – may reduce the risk of obesity and other chronic diseases. During IF, the body is able to achieve a state of ketosis without the need for a low carbohydrate diet. Popular IF protocols include daily IF and alternate day fasting (also known as the 5:2 diet).

Ketosis

Ketosis is a coordinated metabolic response that provides an alternative fuel source derived from fat when glucose is in short supply. Ketosis is normal during fasting, after prolonged exercise, and when a low carbohydrate, high-fat diet is consumed. In recent years there has been increased interest in in very low carbohydrate ketogenic diets (VLCKDs), which restrict carbohydrate, while allowing unlimited amounts of protein and fat. Examples of VLCKDs include the Atkins Diet, The Zone, and The South Beach Diet.

While it is true that low carb diets may promote short-term weight loss, long-term the benefits are a lot loss clear. Especially, considering these diets require avoidance of most fruits and vegetables in combination with excessive intakes of animal products.

A healthier and more sustainable way to achieve ketosis that does not require the avoidance of carbohydrates or entire food groups is intermittent fasting. You can assess whether or not your body is in ketosis with over-the-counter urinalysis strips.

Intermittent Fasting

With daily intermittent fasting (IF), individuals fast for 16 hours 5 to 7 days per week. The eating window is 8 hours and is without dietary restriction. The time spent sleeping is included in the fast.

• Intermittent Fasting = Sleep for 8 hours + Fast for 8 hours + Eat for 8 hours

Alternate Day Fasting

With alternate day fasting, individuals eat “normally” 5 days per week and fast 2 days per week. During the 2 fasting days, food is restricted to 1 meal per day (or less than 600 calories). Participants are free to choose which days they fast and eat normally.

• Alternate Day Fasting = Fast 2 Days Per Week (1 Meal per Day)

One of the biggest supporters of daily intermittent fasting (other than myself), is Mark Mattson, PhD – head of the National Institute on Aging’s Neuroscience Laboratory. In a recent research publication, Mattson claims that fasting only twice per week could significantly lower the risk of developing Alzheimer’s and Parkinson’s disease. I include one of his TED Talks towards the bottom of this page.

My Fasting Regimen

In general, I fast for at least 16 hours each day. I have never been one to eat a big breakfast – I don’t wake up hungry or starving like some individuals report. Perhaps because I eat later at night – I’m not sure, but when I do eat breakfast, it makes me very tired and decreases my cognitive performance throughout the rest of the day (this phenomenon is also reported in the literature).

During my fasting window, I drink green tea (with a small amount of natural sweetener) and water, but I consume no food. Sometimes I will have a piece of gum because going all day without food tends to make your mouth feel sticky. It’s weird, I know. Food – especially plant matter – helps to clean your teeth, believe it or not.

Considering I like to train around 11am – noon, this means I also train in a fasted state; which, is no problem for me. I’ve been doing this for years and my body is absolutely accustom to it. However, it’s important to note that training in a fasted state does accelerate fat loss.

To break my fast, I generally eat 2 bananas with 2 ounces of raw nuts around 2 or 3pm. There’s no rhyme or reason to the bananas and nuts other than they are two of my favorite foods. After my snack, I will eat when I am hungry (no restrictions). I do not weigh my food or count my macronutrients – nor do I impose food rules on myself. I listen to my body and eat when I am hungry. If I’m hungry at 10 pm at night – I eat.

In fact, it is not uncommon for an intermittent faster to consume more calories than someone who is not an intermittent faster and still maintain or lose weight; which, seems to imply the metabolic benefits exist even in absence of calorie restriction.

While I realize some people may have difficulty meeting their energy and/or protein requirements within a restricted time window, this simply isn’t a problem for me. In fact, it’s not uncommon for intermittent fasters to consume an equal or greater amount of calories and still maintain or lose weight; which, seems to imply the metabolic benefits exist even in absence of calorie restriction.

Granted, there are some days that I wake up hungry – maybe once or twice per month – and I will eat fresh fruit those mornings (it may be related to thirst or hormonal fluctuations, I’m not exactly sure, but it’s no big deal. I may feel a little tired throughout the day, but I don’t feel bad about it). Remember, this is a lifestyle for me.

Frequently Asked Questions (FAQs)

Is IF a fad diet?

No. I’ve been an intermittent faster for 15+ years. Long before I even knew it had a name.. When I learned skipping breakfast was referenced as “intermittent fasting,” I was ecstatic. At last, I can tell people to leave me alone about it. “See… other people do it too! Breakfast isn’t for everyone.”

I thought breakfast was the most important meal of the day?

Not really. Recommendations regarding eating breakfast are weak at best (here and here). This claim likely originated from Big Food or someone who really loves breakfast. Mark Mattson, PhD reviews this myth as well in his video below.

Do I need to fast?

No, not at all. Whether or not you should try intermittent fasting is a personal decision. I am describing what works best for me;  you need to do what works best for YOU.

You aren’t hungry when you wake up?

No. Eating early in the day makes me very tired and less efficient throughout the rest of the day.

Will IF help me lose weight?

Probably! The research seems to suggest intermittent fasting promotes weight loss.

Won’t fasting put my body into starvation mode and cause my body to store fat?

No, that is another myth. There is no evidence to support that claim whatsoever.

Would IF help reduce my risk of developing type 2 diabetes?

If it helps you achieve weight loss, probably (source).

If I have type 2 diabetes can I fast?

No. Not without first consulting with your primary care provider and/or healthcare team. Fasting may be harmful to some individuals including those with mental health disorders.

Do you drink water during your fast?

Yes! Of course, staying hydrated is very important while in a state of ketosis.

Can I drink fruit-infused water during my fast?

Totes my oats! Of course..

Can I have coffee?

Yes, just don’t use too much creamer or sweeteners as even 10 grams of carbohydrate may prevent ketosis. I personally drink green tea every morning.

Do you consume any food during your fast?

No.

What about gum? Do you chew gum during your fast?

Sometimes; however, I typically don’t chew very much gum. If you do chew gum, I’d limit it to no more than 1 – 2 pieces as most gum contains carbohydrate (or sugar).

Training on an empty stomach doesn’t hinder your athletic performance?

No, not at all. Many athletes fast on a regular basis for religious (e.g. Ramadan), spiritual, or health reasons.

What about endurance athletes?

There is some evidence to support intermittent fasting in endurance athletes.

What time should I break my fast?

That is a question I really can’t answer; however, it is important to fast for a period of time long enough to reach a state of ketosis (e.g. 16 hours). The time that you choose to start and end your fast is up to you.

I can enter a state of ketosis and still eat a lot of carbohydrates?

Yes, I do it every day.

Can I work up to my fasting goal?

Yes, I recommend that. Especially in individuals who are chronic breakfast eaters. Individuals who have eaten a large breakfast for years may want to consider slowly transitioning to IF. For example, wake up and continue your overnight fast until 9am-10am. If after a week you feel comfortable advancing (and would like to advance), then advance the fast time until 12 noon or 1pm (and so forth). There’s no right or wrong way to develop your IF protocol. It’s whatever works best for you.

After I break my fast, do I need to eat a certain food?

Nope. You can eat normally (eating clean – I hope!).

OK, but what if I eat a high-fat diet?

The evidence seems to suggest that high-fat and low-fat diets produce similar results.

After I break my fast, do I need to stop eating at a certain time at night?

No, not necessarily. I suggest you eat when you are truly hungry (not just bored). I personally do not limit my food consumption during the evening, but it is important to try and avoid viewing this meal time as “the last meal.” The goal is to consume an adequate amount of food to satisfy hunger without overeating and/or binging.

Can I fast at night?

Yes, if you’d like. There are many variations of intermittent fasting. Some people choose to fast in the evening (e.g. stop eating after 6:30pm – 7pm) and then break their fast a few hours after they wake. This schedule would not work well for me as I prefer to eat the majority of my food mid-to-late day (just my personal preference). Chances are, it doesn’t matter which of the daily meals – the first or the last – is omitted as long as the interval is long enough to promote a state of ketosis (source).

Posters and Charts

Except where otherwise noted, content on this site is licensed under a CC BY-NC-ND 4.0 license. This means you are free to use my work for personal use (e.g., save the file to your computer or share via social media) as long as you do not modify the image or use the image for commercial purposes ($). Big hugs! Dana

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