“A Good Fast is better than a Bad Meal” ~ Old Irish Proverb
“He who eats until he is Sick must Fast until he is Well.” ~ Old English Proverb
“Dr. Gonzalez! There is no way I can starve myself!” That is the usual response when I recommend intermittent fasting to my patients. Fortunately, it is easier than you think and can be a powerful tool for improvement of body composition and healthy longevity.
Over the decades doctors and nutritionists have been solely focused on what to eat for health and weight loss. More recently, scientists have recognized that we should also be concerned about WHEN we should be eating as part of our dietary approach to overall health and wellness.
For centuries, fasting has been a large part of religious experiences including all factions of the Christian, Jewish, Buddhist, Hindu, and Muslim faiths. Religious fasting has various intentions including bringing oneself closer to God or self awareness, to physically and spiritually purify oneself, and to become closer to an understanding of world suffering and solutions. An example of a modern day religious approach to fasting is exemplified by the Church of Jesus Christ of Latter Day Saints where members fast for 24 hours on the first Sunday of each month. Members are encouraged to donate the money usually used for food towards benefitting those less fortunate. The common denominator for religious fasting is purposeful giving and mindfulness for the improvement of an individual’s health and overall wellness.
In the late 19th century, Dr. Edward H. Dewey, a famous Civil War Surgeon and U.S. Assistant Surgeon General, wrote a series of books and articles on intermittent fasting for health and the improvement of multiple social ills. More recently, scientists have looked closer to intermittent fasting as a powerful tool for weight loss and longevity.
What is the definition of fasting? It turns out there is no single definition in the scientific literature. However, there are 3 common approaches:
- Meal skipping for a 24 hour period
- Alternate Day fasting where you eat approximately 400 to 600 calories total for one day then eating as you would normally the following day and repeating this pattern.
- Timed restricted feeding where you eat as you normally would during an 8 hour period then fasting during the remaining 16 hours.
Each of these has different variations to the base and all have been shown to have some sort of physiologic benefit. Intermittent fasting has gained a lot of attention in obesity and “anti-aging” research. Two key questions need to be answered:
- Does it really work for weight loss and longevity?
- Is intermittent fasting safe?
It turns out there is good literature support on both the safety of fasting and the positive effects on health. Both animal and human studies have supported intermittent fasting for weight loss, the maintenance of healthy weight, improvements in blood pressure, blood sugar, and the slowing of the aging process overall. Dr Volter Longo, the Director of the University of Southern California Longevity Institute published a human study earlier this year showing that a 5 day modified intermittent fasting diet done once a month for 3 months helped individuals lose body fat, waist size and weight, improve BMI and overall laboratory health markers without adverse side effects. Dr. Longo admits there is a need for more studies but says this approach to intermittent fasting has the best promise for improved overall health, quality of life, and healthy longevity.
Intermittent fasting has been shown to increase your body’s ability to produce more growth hormone naturally, improve insulin sensitivity thus allowing your body to access fat storage more readily, allow for cellular repair by breaking down old cells and building new ones, and help turn off the genes that cause aging, and keep the youth genes going longer.
These are my general guidelines and overall recommendations:
First, NEVER begin a fasting diet without proper physician advice. I have seen individuals come to urgent care and emergency rooms with starvation symptoms simply because they did not have proper medical guidance. So what about juice cleanses as a way to intermittently fast and diet? There is no scientific evidence that juice cleanses improves long term health. Juice cleanses alone may give temporary improvement in bowel habits but most are highly marketed BS that offer no long term health or weight improvements.
Never begin a fasting diet without talking to your medical physician or to a physician who specializes in metabolism or obesity medicine. There is no final word on fasting in the medical literature. Intermittent fasting can be a great tool for maintaining proper weight loss. I recommend specific programs in my clinic that are supported by medical literature to actually benefit long term health.
Fasting is easier than you think. Remember, over 1/3rd of the world’s population voluntarily fasts safely. Fasting needs to be purposeful in order to be effective. Fasting Mimicking Diets can be powerful tools for improved health and longevity. Proper monitoring with baseline labs and biometric measurements by your doctor can ensure you reach your goals and long term success.
“The best of all medicines is resting and fasting” ~ Benjamin Franklin
To Your Health,
Executive Summary: Guidelines for the management of overweight and obesity in adults. Obesity Society and the American College of Cardiology/ American Heart Association Task Force on Practice Guidelines. Obesity 2014; 22:s5-s39.
Conley M. et al. Is two days of intermittent energy restriction per week a feasible weight loss approach in obese males? A randomized pilot study. Nutr Diet. 2017 Aug 9.
Wei M. et al. “Fasting-mimicking diet and markers/risk factors for aging” Sci Transl Med. 15 Feb 2017; 9(377).