NORTH FORK, CA – Fasting has been used for thousands of years for religious and health reasons.  It is simply not consuming food for a period of time, usually including water as the only beverage.  Early medical practices used fasting for various illnesses, believing it helped the body’s natural healing processes.  Religious traditions use fasting as a means for achieving moral, spiritual, or communal benefits, not for physical health.

This article is about the potential health benefits and risks of fasting.  Consider what you want to accomplish from a fast:  lose weight, feel better, have more energy, be healthier?  There is no “right” way to fast.  Listen to your body.

Types of Fasting Used For Health Reasons

The variety of ways to fast are endless.  Here are a few common terms used today.

• Time-restricted Eating (TRE) – meals are consumed within a limited number of hours (such as 8-12 hours) each day, with nothing consumed during the other hours.
• Alternate-day fasting – Eating is unrestricted every other day, and no calories or very few consumed on the days in between.
• 5:2 eating pattern – Eating is unrestricted for 5 straight days each week, followed by 2 days of restricted caloric intake.
• 1 day fast – Full 24 hour fast each week
• Periodic fasting – Caloric intake is restricted for multiple consecutive days, such as 5 days in a row once a month, and unrestricted on all other days
• Fasting – Simply not eating for a short or extended period of time, usually still drinking water.

Possible Health Benefits of Fasting

Most research has focused on the weight-loss aspect of fasting, primarily in obese people, and only a few small clinical trials have been done.  More work is needed to determine if any types of fasting diets have long-term benefits.  These are the things that many claim fasting can provide, but human evidence is weak.

• Weight loss
• May help athletic performance
• Normalize insulin sensitivity
• Balance ghrelin levels, reduce leptin
• Protect heart health
• Slow signs of aging
• May help lower markers of inflammation
• May help cognition and lower risk of Alzheimer’s
• May help with cancer prevention and treatment

Risks of Fasting

Short-term mild calorie deficits are generally safe for many people if done carefully.  Problems can arise when the deficit is large, prolonged, or combined with high stress, poor sleep, or overtraining.

• Electrolyte imbalances
• Low blood sugar
• Dehydration
• Disrupted sleep
• Irritability
• Inadequate nutrition for bodily functions
• Muscle and bone loss
• Gallstones
• Hormonal effects
• Increased susceptibility to illness

Prolonged calorie deficits that can happen with or without fasting can be very harmful.  Women’s reproductive systems are very sensitive to energy availability, and reproductive hormones can be shut down.  This leads to infertility when the body stops ovulating, and even complete loss of menstrual cycles.  Pregnancy is a metabolically expensive process, so the body errs on the side of caution.  Also, thyroid function can be suppressed, and there is bone density loss.  Men can experience lower testosterone, though they generally need a larger or longer deficit to trigger this.  Both men and women can lose muscle mass, have a lower metabolic rate, and increased cortisol.  (See article:  The Cortisol Connection.)

Under-eating is a quiet, widespread problem, and often not visible.  Most people are at completely normal weight or even higher body weight, while in a state of relative energy and nutrient deficiency.  This can result from intentional calorie restriction or just not realizing intake is too low for the body to function properly.  Surveys show women in many Western countries consistently eat below their energy needs, especially those that are physically active.  Women have had decades of advertising pressure that links being thin to beauty and worth.

Should You Try Fasting?

Fasting is not for everyone.  People with these conditions should avoid fasting or have medical supervision:

• Hypoglycemia or diabetes
• Pregnant and breastfeeding women should NOT
• Consult your doctor if you have a health condition and take prescription medications
• Thyroid issues or fatigue
• Eating disorder
• Children and adolescents should NOT, they need calories to develop properly
• History of low blood pressure or fainting
• Underweight
• Certain GI conditions, such as ulcers or GERD

There are no firm conclusions about the benefits and safety of fasting for human health.  A huge number of processes keep the human body functioning, and it is difficult to determine how these are affected under different dietary conditions.  Also, humans are very different from each other – gender, size, age, environment, lifestyle and other factors.  An eating pattern that helps one person might not have the same effect on another.  Furthermore, what is needed for an individual person varies widely from day to day, and year to year.

Despite the numerous health claims about the benefits of various types of fasting, there is also evidence that it may not be healthy.  There is a study that concluded “TRE with eating duration <8 hours was significantly associated with a higher risk of cardiovascular mortality in the general population as well as in people with cardiovascular disease or cancer.”  (Association Between Time-Restricted Eating and All-Cause and Cause-Specific Mortality.)

There is plenty of evidence for other choices that you can make to help you stay healthy:

• Eat a nutritious diet in moderate amounts
• Get regular physical exercise
• Do not drink alcohol and do not smoke
• Maintain an active social life
• Get a good night’s sleep

Hunger is a normal sign from the body that you are not providing enough fuel for it to function properly.  Listen to it carefully.

Read additional articles here:  Focus On Vibrant Health.  Topics previously covered include the basic lifestyle choices that support your health.

Dr. Veronica Tilden can be your ally in having vibrant health.  She uses traditional hands-on osteopathy and helps you take responsibility for your health, guiding you to make better choices in your life.  She brings her 30 years of experience to her hometown at her office in North Fork.  You can find out more and schedule an appointment at DrVeronicaTilden.com.