"What is all the buzz about fasting?"
"Is it effective for weight loss?"
"Is it safe?"
"And how in the heck do you do it?"
These are all questions I get from my clients that are interested in using fasting to lose weight. First of all, yes it helps with weight loss! Second of all, yes it's safe, as long as it's done correctly.
And as for how you do it....well that is a longer answer.
Before you start any fasting you'll need to know the basic types of fasting so you can choose the style that is right for you.
There are several different approaches to fasting
- 12-13 hour nightly fast
- Intermittent fasting/Time-Restricted Feeding such as the 16/8 Intermittent Fasting
- Prolonged fasting
- Fasting Mimicking Diet
A nightly 12-13 hour fast is recommended for everyone. Ideally we all stop eating by 6-7 PM every night or at least regularly.
Intermittent fasting involves fasting daily or regularly for 24 hours or less. Usually this is a 16-hour, 18-hour or 24-hour fast. So if you stop eating at 7 PM you may not eat again until 11 AM to 1 PM the next day. Or some people eat only dinner every day. The 16/8 Intermittent Fasting is the most commonly used style these days.
Prolonged Fasting is anything over 24 hours. This is only recommended to be done under medical supervision. This type of fasting can range from 36 hours to several days to several weeks. Usually this is a water-only fast. This type of fasting is usually used to “cleanse” or to facilitate healing from specific diseases such as cancer, GI disorders, and autoimmune disease.
The Fasting Mimicking Diet (FMD) is a technique of using very low caloric intake to “trick” the body into thinking it’s fasting.
The 5:2 Diet has popularized this idea. This is where you eat normal calories 5 days a week and then you eat 500-600 calories per day for 2 non-consecutive days each week.
Another FMD was designed by Dr. Valter Longo and has been studied in a clinical trial. This approach involves using a meal kit that you purchase from a company called Prolon and eating only those foods for 5 days straight. It should be done under medical supervision. The FMD can be done no more than once a month. Prolon is now developing a kit for cancer patients, as this technique seems to help accentuate the efficacy of conventional cancer treatments.
Now that you know the different types of fasting you may be wondering which one is right for you.
Ideally you would consult with a healthcare practitioner to best determine that. But certainly most people can start with a 12-13 hour fast nightly.
If you were to stop eating at 7 PM in the evening, by 3 or 4 AM you would be burning predominantly fat for fuel. So imagine if you didn't eat until 8 AM? That would be 4-5 hours of intense fat burning! How cool is that? And it is safe for almost everyone to do this.
And no matter what type of fasting you choose, I recommend starting with this overnight fast first. That way you can get acclimated to eating less often.
After that, if you want to start experimenting with longer periods without eating, go for it!
But please read the cautions below to make sure it's safe for you to try on your own.
Cautions About Fasting
- Ease into it, start with nightly 12-hour fast, then slowly increase
- People with diabetes need to be under the care of a medical doctor for fasting
- People on medications need to be under the care of a medical doctor for fasting
- Fasting is contraindicated (should NOT be done) for children, pregnant and lactating women, and anyone that is malnourished or underweight (below 18% body fat)
- Be sure to stay well-hydrated during fasts and take in electrolytes and minerals
- Do not gorge to break a fast, do so with small amounts of food
- Avoid fasting in order to get away with eating junk food
- During a fast you can still consume water, black coffee, herbal, green, or black tea, and bone or vegetable broths.
All the wonderful benefits of fasting
- Weight loss
- Increased longevity
- Increased mental clarity and focus
- Better insulin and blood sugar control
- No down-regulation of metabolism like most diets
- Simple, easy, convenient, inexpensive (saves you money!)
- Goes along with any dietary restrictions
- Cleans out “old” and damaged proteins and cells
- Better stress response
- Prolonged fasting and regular FMD have been shown to reduce autoimmune activity, increase stem cell production, and reduce risk for cancer, diabetes, and cardiovascular disease
Further Reading About Fasting
Influence of short-term repeated fasting on the longevity of female (NZB×NZW)F1 mice
https://www.scientificamerican.com/article/how-intermittent-fasting-might-help-you-live-longer-healthier-life/2013. How Intermittent Fasting Might Help You Live a Longer and Healthier Life
Short-term modified alternate-day fasting: a novel dietary strategy for weight loss and
cardioprotection in obese adults.
Intermittent fasting vs daily calorie restriction for type 2 diabetes prevention: a review of human findings
Effects of intermittent fasting on health markers in those with type 2 diabetes: A pilot study
Fasting-mimicking diet and markers/risk factors for aging, diabetes, cancer, and cardiovascular
Effects of intermittent fasting on body composition and clinical health markers in humans.
Metabolic and molecular framework for the enhancement of endurance by intermittent food
Diminished energy requirements in reduced-obese patients.
Long-Term Persistence of Hormonal Adaptations to Weight Loss