Fasting Diets

In the past 60 years obesity rates in the US have tripled from 13% in the 1960’s to 43% today. Nearly 70% of Americans are either overweight or obese. Struggling with excess weight is a daunting reality for far too many Americans. Fasting diets have arisen as a possible solution. The question remains: are they helpful in the long run or harmful?

Intermittent Fasting
Alternating episodes of eating and fasting describe the pattern of intermittent fasting (IF). The Leangains Protocol also known as the 16/8 Method is the one most used. Participants fast for 16 hours and eat for 8. Two meals a day are recommended while bingeing is discouraged. Breakfast is the meal most often skipped.

The Eat-Stop-Eat Method involves a 24 hour fast twice a week. While the 5:2 Diet reduces calories to <500 to 600 on 2 days a week.

3 Day Water Fast
Perhaps the most challenging is the 3 Day Water Fast where primarily only water is consumed. In the first 24 hours the glycogen or sugar stored in the liver and muscles is burned for energy. After 24 hours fat is broken down for energy producing ketones as a byproduct. The ketones in the blood create an acidotic state that over time may change gut bacteria, reduce bone health, damage kidneys and lead to increased risk for cancer and other diseases. Keto Flu symptoms include headaches, brain fog and fatigue.

Benefits of Fasting
A review study was done between 2000 and 2019 examining 27 small studies. Most of the study groups had <50 participants and lasted only between 2 and 26 weeks. Validity is required for much larger numbers and a longer length of time. However, it did indicate that there may be a benefit for some intermittent fasting but much more research is needed to better understand the benefits and harms. Some promising benefits include:

—Autophagy may occur after prolonged fasting that begins to repair and renew cells. It may play a role in cancer prevention.

—Reduced risk factors for heart disease by lowering blood pressure and improving abnormal cholesterol numbers.

—Improved insulin effectiveness and glycemic or glucose metabolism.

—Enhanced leptin an appetite suppressant which helps one feel full.

—Weight loss

Dangers of Fasting
Obviously the longer the fast, the greater the risk of adverse consequences. The 3 Day Water Fast is the most dangerous for a variety of reasons but everyone should use caution and speak with a healthcare provider before engaging in any fasting eating pattern. The harms may include:

–Dangerous Hypoglycemia (low blood sugar): Severe calorie restrictions play havoc with diabetic medications and MUST NOT be attempted without a healthcare provider’s supervision!

—Electrolyte Imbalances: Too much water flushes sodium out with the excess water recommended during the fast. Hyponatremia (low sodium) is a dangerous deadly condition that may result.

—Gout Eruption: Anyone with a history of gout should also speak with a healthcare provider as severe dehydration and calorie restriction enhances uric acid formation.

—Orthostatic Hypotension: Low blood pressure may occur when standing suddenly.

—Nutritional Deficits: Lack of a variety of food depletes key vitamins and minerals needed to enhance immunity and body functions.

—Muscle Loss: In general, the greater the muscle size, the higher the metabolism. Longer term fasting results in muscle loss.

—Dehydration:  Food provides 20% to 30% of daily water hydration and is depleted when fasting.

—Psychological Complications: Exacerbation of eating disorders, discouragement and despair when the weight returns.

Refeeding Syndrome
This problem occurs if too much food is consumed following fasting, especially after a 3 Day water fast. During the fast key nutrients have been depleted and the body adjusted to the starvation state. Adding too much food too fast may induce severe electrolyte abnormalities that alter the function of the heart, lungs, brain and kidneys. It induces a myriad of serious potentially lethal complications. Again, working with a healthcare provider is the safest approach to prevent this potentially lethal complication.

 

What Does Work?
I’ve counseled many people on proper weight management that is maintained over time. The following recommendations have been the most helpful for continued success.

—The Mediterranean Diet: This eating plan remains the most effective and best tasting strategy for people across the world.

—Set Up your Environment for Success: Remove those foods that lead to binge eating. If it’s not good for you it’s not good for your children either. Brian Wansink’s book Mindless Eating describes those unconscious mistakes that sabotage the best of intentions.

—Don’t Drink your Calories: Sweetened coffee, alcoholic beverages and sodas are killers.

—Increase Protein in your Diet: Protein throughout the day helps stabilize blood sugar levels and reduce cravings.

—Reduce your Portion Sizes.

—Eat a Variety of Fruits and Vegetables.

—Increase your Muscle Mass: Bigger muscles increase metabolism while at rest as you burn extra calories.

—Go for a walk, get a good night’s sleep and destress your life.

On A Personal Note:
I’ve maintained a healthy weight all my life. I enjoy the food I love in smaller portions, have added more protein to my diet, and working on increasing my physical activity. This past fall I had a knee replacement. Due to an allergy to the adhesive in the dressing I had to be on Benadryl for a week. It completely reduced my appetite and broke a lifelong sugar craving.

It was all I could do to get the Ensure down that I needed to heal.

However, 9 months later I’ve maintained the 20-pound weight loss. I don’t crave sugar as I did before. I may have a sweet, but it just doesn’t taste the same. Consider a sugar break for 2 weeks. You’ll be shocked how it will also help end your sugar addiction.

Personally, I use a modified 16/8 fast. I eat a very small portion of either a small amount of yogurt, a handful of nuts or a piece of peanut butter toast for breakfast. The protein lingers filling me up until lunch. If’ I’m hungry I eat a palm size of peanuts. Honestly, I’m shocked how it works.

Maintaining a healthy weight is a challenge in a world filled with wonderful food and enormous portion sizes. But you can do it! Try a few of these tips and if you do decide to try a fast, please check with your doctor.

May God bless you as you try some new strategies to maintain a healthier weight over time.

 So, whether you eat or drink, or whatever you do, do all to the glory of God (1 Corinthians 10:31).

I’m a Christian nurse who helps people navigate the murky waters of healthcare
References:

USA Facts Team, “USA Obesity Rates Tripled Over the last 60 Years,” USA Facts (March 21, 2023). https://usafacts.org/articles/obesity-rate-nearly-triples-united-states-over-last-50-years/

1. Gunners, “Intermittent Fasting 101-The Ultimate Beginner’s Guide, Healthline, Nutrition (May 3, 2024). https://www.healthline.com/nutrition/intermittent-fasting-guide

1. Mitri, “Fasting for 3 Days: Is It a Game -Changer for your Metabolism or a Risk not Worth Taking?” Welltech/Well Hub (January 1, 2025). https://welltech.com/content/fasting-for-3-days/

1. Streit, “7 Keto Risks to Keep in Mind,” Healthline (March 25, 2025). https://www.healthline.com/nutrition/dangers-of-keto-diet#5-May-cause-dangerously-low-blood-sugar

Welton et al., “Intermittent Fasting and Weight Loss, Systematic Review” Canada Family Physician (February 2020). https://pmc.ncbi.nlm.nih.gov/articles/PMC7021351/

1. Raman, “Water Fasting: Benefits and Dangers,” Healthline (October 10, 2022).

https://www.healthline.com/nutrition/water-fasting

“Refeeding Syndrome,” The Cleveland Clinic (June 6, 2022). https://my.clevelandclinic.org/health/diseases/23228-refeeding-syndrome

1. Wansink, Mindless Eating: Why We Eat More than We Think (December 28, 2010). https://www.amazon.com/Mindless-Eating-More-Than-Think/dp/034552688

I’m a Christian nurse who helps people navigate the murky waters of healthcare.

Paperback copies of both books for sale. Email me for details at:  ask@jenniejohnsonrn.com.