Weight Management: Intermittent Fasting

Intermittent Fasting

Fasting is a period of time that you are not eating. Intermittent fasting (IF) is alternating between periods of fasting and eating.  

Studies of intermittent fasting support its effectiveness in weight loss. How does this happen? 

When you don’t eat for a period of time, your insulin levels fall. This results in the release of stored sugar from your fat cells. Your body uses sugar for energy. If your insulin levels are low enough for a long enough period of time, you will burn fat and ultimately lose weight.

Types of Intermittent Fasting

There are various ways to use IF - i.e. various intervals of eating and fasting. The most common forms are the 16/8 method, circadian rhythm fasting, eat-stop-eat fasting, and the 5:2 diet

16/8 Method

You skip breakfast and only eat for an 8-hour period every day. You might only eat from 11:00 AM to 7:00 PM or 12:00 PM to 8:00 PM. You fast for the other 16 hours. This is the most commonly used type of IF. It is safe as long as you get the nutrition you need during the time you are eating. 

Eat-Stop-Eat Fasting

You fast for 24 hours, once or twice a week. That means you don’t eat from dinner one day until dinner the next day - on one or two days each week.

5:2 Diet

It’s called the 5:2 diet because five days of the week are normal eating days, while the other two restrict calories to 500–600 per day (Note: the two days should not be back-to-back). 

"Normal eating days" does not mean you can eat anything! On those days you should have nutritious foods that are high in fiber and high in healthy protein. These foods will help you feel full without having too many calories.

Circadian Rhythm Fasting

Another type of fasting is called circadian rhythm fasting. You time your meals to align with your body’s internal clock based on the 24-hour light/dark cycle, which is the circadian rhythm.

While it is similar to intermittent fasting, the circadian rhythm diet has stricter timing. It requires that you stop eating by 7:00 PM. It also encourages eating breakfast. 

Intermittent Fasting And Eating

IF does not mean that you eat as much as possible in a specific number of hours. Instead, try to make it part of your lifestyle. The goal is to be mindful and take pleasure in eating high-quality and nutritious food.

For the best results, follow a Mediterranean diet with nutrient-dense foods. You should include unrefined carbohydrates, healthy fats, leafy greens, and lean protein while limiting processed foods and refined carbohydrates.

Your coach can help with food choices and meal ideas.

How To Get Started

The 16-8 method most closely follows your normal 24-hour sleep/wake cycle, but is somewhat more flexible. You, generally, fast when it’s dark and eat when it’s light. If you never used IF, we recommend this method over the others. 

To get started:

  • Stop eating two to three hours before bedtime

  • Gradually lengthen the time you’re fasting until it is about sixteen hours - 16 hours of fasting and 8 hours of eating. 

  • For example, you stop eating at 9:00 PM, two hours before going to sleep at 11:00 PM. You wake up at 8:00 AM and eat breakfast at 9:00 AM. Once this is comfortable, you might stop eating at 8:30 PM with an 11:00 PM bedtime, an 8:00 AM wake-up time, and breakfast at 9:00 AM - and so on.

Hydration

When it comes to fasting, a lot of emphasis is placed on food - this makes it easy to forget about staying hydrated!

Approximately 20% of your fluid needs are met from food. Carbohydrates like oatmeal, pasta, and brown rice absorb water while cooking. Other foods like soup, watermelon, and many vegetables contain a lot of water.

Even if you have the amount of water you usually drink, you’re not getting water from these food sources during your fasting time. This puts you at risk for dehydration - i.e. when your body doesn’t have enough fluids. 

Healthy adults need around 30–35 mL of water per kg of body weight to make sure they are meeting their minimum hydration needs.

Will It Break My Fast?

You may wonder whether or not you can eat or drink anything during the time you are fasting. See this guide for what you can have while fasting:

Does It Break the Fast?

  • Black coffee: it does not

  • Coffee with cream or half & half: it does not in small quantities (limit cream or half & half to 1 Tbsp (15 mL) per 1 cup (240 mL) of coffee)

  • Tea: it does not

  • Lemon juice in hot water: it does not if less than 3 oz (84 mL) lemon juice

  • Bone broth: it does not

  • Sugarless chewing gum: it does not

  • Apple cider vinegar: it does not

  • Water and seltzer/sparkling water: it does not, as long as it is naturally flavored and calorie-free

Cautions

While fasting has many benefits, use caution if any of the following are present:

  • You are underweight

  • Have increased anxiety or stress

  • Have a history of an eating disorder

  • Have diabetes

  • Have low blood pressure

  • Have gastroesophageal reflux disease (GERD/GORD)

You should not fast if you are trying to conceive, are pregnant, or are breastfeeding.

Consider talking to your doctor before starting a fasting diet, especially if you have any underlying health conditions.

Disclaimer 

While intermittent fasting (IF) has many proven benefits, it’s not the best approach for everyone. IF should not be viewed as a substitute for a balanced, well-rounded diet, rich in whole foods.