Become a Member

Get access to more than 30 brands, premium video, exclusive content, events, mapping, and more.

Already have an account? Sign In

Become a Member

Get access to more than 30 brands, premium video, exclusive content, events, mapping, and more.

Already have an account? Sign In


General Health

5 Things You Should Know About Intermittent Fasting

Intermittent fasting may improve fat loss, but how do you do it, and how does it work?

Get access to everything we publish when you sign up for Outside+.

Learn more about the benefits of intermittent fasting in our 28-Day Real Food Reboot on Outside LEARN. This reboot will help you discover how to transform your relationship with food and form healthier habits that better serve you and those around you. This boot camp includes weekly meal plans, a mix ’n’ match recipe manual, and an optional exercise plan for those looking to incorporate movement. 

Many low-carb eaters use intermittent fasting (IF) to complement their lifestyles. IF means eating within a certain time frame and abstaining from eating for the remainder of the time. Fasting allows the digestive system to rest and heal and has a positive influence on the gut microbiome (the balance of bacteria, yeast, and other microbes living inside the digestive tract). Fasting has been used for centuries in many different cultures for healing, detoxification, and religious reasons. Here are a few things you may not have known about this blazing-hot trend.

1. You May See Big Benefits with Intermittent Fasting.

Some of the benefits of IF include weight loss, blood sugar control, improved fat burning, mental clarity, decreased inflammation, and autophagy (the body’s ability to repair itself). Fasting allows the body to burn body fat (in the form of ketones) for fuel, providing a good source of energy, and may ultimately result in reduced body-fat stores.

2. You Can Adjust The Fasting Window To Work For You

There are different ways to fast. Shorter fasts (less than 24 hours) may have a 16- to 18-hour fast and a 6- to 8-hour feeding window. Usually, people will delay their first meal of the day and just have lunch and dinner. Longer fasts (over 24 hours) are done less frequently and may have profound healing effects on the digestive system. Always check with your doctor first before attempting any fasting protocol, as certain medications (such as those for blood pressure and blood sugar) may need to be adjusted as fasting will likely lower both blood pressure and blood sugar levels.

Related: What Is Intermittent Fasting?

3. Intermittent Fasting Boosts Fat Burning

Fasting helps stimulate the production of human growth hormone (HGH), which can increase the availability and utility of fat for fuel by raising levels of key enzymes. HGH also helps preserve bone density and muscle mass.

4. Not Everyone Should Fast

Pregnant or breastfeeding women, children and underweight individuals require more calories for proper growth and adequate nutrient intake, so IF is not advised. In addition, people with eating disorders or disordered food-thought patterns will more likely be triggered by IF, so it’s best avoided in that case, too.

5. You Can Manage Side Effects

Possible side effects of IF include constipation, headaches, dizziness, heartburn and muscle cramps. Many of these are due to dehydration and electrolyte imbalances that can occur with lowered intake of salt and water. Make sure to stay adequately hydrated and add some pink Himalayan sea salt to your water or consume bone broth. Epsom salt baths are a good source of magnesium, which will help with muscle cramping. Breaking the fast with a large meal can result in heartburn so keep the first meal light and stay upright afterwards to allow time for food to digest.