Is Fasting Healthy?


Fasting has become an increasingly popular diet trend in recent years, with those who practice fasting diets yelling their praises from the mountaintops. However, it’s normal to question whether or not fasting for an extended period of time is healthy. In this article, we will go over what exactly intermittent fasting is, examples of fasting diets, and the possible health effects it may have on you. 

How Does Intermittent Fasting Work?

Intermittent fasting has become incredibly popular in recent years, quickly becoming one of the most common diets. Intermittent fasting involves cycling between periods of eating and fasting. The most common type of diet is the 16/8 intermittent fasting diet, which involves a 16-hour fasting period and an 8-hour eating window. 

There are also more extreme fasting diets that involve fasting for a full 24 hours once or twice per week, or significantly cutting calorie intake a few days per week. While these diets may seem harsh, we technically practice a form of intermittent fasting every time we go to sleep. Simply skipping out on breakfast could have you well on your way. 

Is Fasting Bad?

If you are relatively healthy and stay hydrated during a fast, fasting for a few days shouldn’t cause any issues. Most fasting diets, such as the 16/8 and 12/12 intermittent fasting diets, are safe for healthy individuals. However, most doctors do not recommend fasting for a long period of time. 

This is because your body needs vitamins, minerals, and other nutrients from food in order to function properly. If you don't get enough, you can have symptoms such as fatigue, dizziness, constipation, dehydration, and not being able to tolerate cold temperatures. Fasting too long can be life-threatening. If you have diabetes, you should avoid even short fasts as it can lead to dangerous dips and spikes in blood sugar. Women who are pregnant or breastfeeding should also avoid fasting. 

How Long is it Safe to Fast?

To keep safe, it’s recommended that you consider limiting your fast periods to 24 hours or fewer. While it is possible to go weeks without food at a time, it is very much recommended that you don’t regularly go over the 24-hour mark. You should also always keep a snack on hand just in case you start feeling faint or ill. 

If you do become ill or are concerned about your health, make sure you stop fasting straight away. Some signs that you should stop your fast and seek medical help include tiredness or weakness that prevents you from carrying out daily tasks, as well as unexpected feelings of sickness and discomfort.

Which Intermittent Fasting is Best for Weight Loss?

There is research that points to the idea that there’s virtually no difference between those who partake in intermittent fasting versus those who simply cut back their calorie intake. Some believe the better strategy is optimizing the nutritional quality of what you already eat. Also, science suggests any potential benefit from fasting is quickly undone during the eating part of the cycle, in which appetite-suppressing hormones switch gears to make you feel even hungrier than you felt at baseline.

However, an intermittent fasting diet plan 16/8 can be very beneficial for those who have trouble sticking to prescribed meal plans or restrictive diets. It should be noted that fasting provides benefits that extend beyond losing weight. Fasting can give your vital organs, digestive and absorptive hormones, and metabolic functions a break. It can also induce autophagy, which is the body’s way of replacing old, dying cells with newer, healthier cells. This can help improve your longevity, leading to a longer, healthier life. 

Is Dry Fasting Good for the Body?

Dry fasting is when you completely avoid both food and liquid over an extended period of time. Nearly every doctor would recommend against this diet, as when it comes to fasting, it is incredibly important that you stay hydrated. Of course, not drinking any liquid during the fasting process can make that difficult. Here are some of the complications that may pop up during a dry fast:

  • Dehydration - This may result in electrolyte imbalances and low blood pressure, which can be life-threatening
  • Urinary and kidney problems - Dehydration can lead to urinary tract infections and kidney stones
  • Fainting - Both dehydration and hypoglycemia increase your risk of fainting
  • Disordered eating - Some people are more likely to binge eat after fasting
  • Nutrient deficiencies - Vitamin and mineral deficiencies are associated with continuous fasting

There are healthier, safer ways to fast or lose weight. If you’re interested in fasting, talk to your doctor first.

Which Fasting Diet is Best?

So what exactly does a fasting diet plan look like? Keep in mind, these diets do not dictate what foods you should or shouldn’t eat. These diets dictate how many hours during the day you can eat. Here are some common types of fasting diets:

  • The 16/8 method - As mentioned earlier, this method involves a 16-hour fasting window. While this may sound extreme, it can be as simple as not eating anything after dinner and skipping out on breakfast
  • 12-hour intermittent fasting - This plan has a 12-hour fasting window. This can be as simple as skipping out on breakfast
  • 5:2 diet - This diet involved eating normally five days of the week and restricting your calorie intake to 500-600 for two days of the week. It is highly recommended that you space these days out
  • Eat Stop Eat - The Eat Stop Eat diet is a more extreme version of the 5:2 diet. This diet requires you to eat normally five days a week, and fast for 24-hours for two days. You can accomplish this by eating dinner one night and waiting for a full 24-hours to eat dinner again. You don’t necessarily have to go the entire day without eating
  • The Warrior Diet - This diet is essentially an all-day fast with a small eating window. The idea is that you only eat small amounts of vegetables and fruits throughout the day, then a large meal at night

As you can tell, some of these diets are more extreme than others. Before starting a diet that requires 24-hour fasting windows, you should consult with your doctor to ensure it’s safe. These diets are not intended for pregnant women or those with diabetes. 

Supplements Can Help

One supplement that can help you get the most out of your fasting diet is spermidine supplements. This is because spermidine helps induce something called autophagy. This is the body’s process of replacing old and potentially damaged cell parts with newer, healthier ones. Autophagy literally means ‘self-eat.’

This process helps keep you feeling and looking young while also dramatically lowering your chances of developing aging diseases such as Parkinson’s and Alzheimer’s. While it is possible to get your recommended daily intake of spermidine through your diet, it’s recommended to take supplements so you ensure you get the right dose. Simply taking your supplements with your dinner is a great way to remember to take spermidine supplements every night. 

  • Don Moxley - Director of Applied Science

    Don Moxley is the Director of Applied Science at Longevity Labs. Moxley draws upon his career as an athlete, a sports scientist, and an instructor to lead and educate on the science of autophagy and longevity.