By now, you’ve likely heard the buzz surrounding intermittent fasting and may be wondering if it is worth a try. While the research is promising on the benefits, it may not be for everyone. Read on to learn the different methods of fasting and the benefits and risks of this style of eating.
What is intermittent fasting?
Fasting is a period of abstaining from food for a sustained period of time. During this time, beneficial metabolic changes occur. Man has evolved to survive periods of food shortages and has created adaptations to keep us strong during brief periods without food.
We’ve created a lifestyle in the US where food is available 24/7, and people never experience the fasted state that we’ve evolved to have. Some may argue that going through periods without food is beneficial to your health. Intermittent fasting offers a way to safely tap into the metabolic potential that fasting offers without doing extended and potentially dangerous fasts. It involves regularly set periods or abstaining from food.
What are the different types of intermittent fasting:
There are several different forms of intermittent fasting that have become popular, and we’ll explore them here:
- Time-restricted eating – this is a daily plan where you don’t eat for a set period and only eat during a “feeding window.” Fasting periods can range from 12 to 16 hours. 16:8 is a popular method of time-restricted eating where your eating window is 8 hours, and you fast for 16 hours daily
- Alternate day fasting – this form of fasting requires you to fast every other day for 24 hours
- OMAD (one meal a day) – exactly as it sounds, with OMAD, you only eat one meal a day. When following this protocol, fasters typically go 18-24 hours between that one meal a day.
- Fasting mimic diets (FMD) – popularized by Dr. Valter Longo, Director of the Longevity Institute at the University of Southern California, this is a very low-calorie program that allows you to eat limited foods while it mimics or tricks the body into thinking it’s in a fasted state. Some people will also use “bulletproof coffees” or non-caloric drinks where medium-chain triglyceride (MCT) oil has been added to help ward off hunger and boost ketone production. Some may argue that a ketogenic diet can be considered a mimic fasting diet. While all of these programs cannot truly be considered fasting, they promote similar metabolic effects in the body.
How does fasting work? – the science of fasting
What are the benefits of intermittent fasting?
Humans have been fasting in some form or another since the dawn of time. Scarcity in food has caused the human body to evolve to handle short periods without food. In addition to times of food shortages, man has used fasting both for religious and therapeutic reasons. Because of this, we have anecdotal evidence that fasting is safe and potentially beneficial for many people.
- Over the past few years, extensive research has been conducted, further demonstrating the efficacy and safety of fasting.
- Weight Loss – truthfully, most people turn to intermittent fasting for weight loss, and the science does indicate that it might be helpful here. It’s no surprise that with skipping meals while you fast, you will decrease the amount of calories you consume, and this may play a role in weight loss, yet weight loss appears to happen even if there are no changes in calorie intake. Studies also demonstrate that when weight loss occurs from fasting, fat is lost as opposed to lean muscle, and decreases in waist circumference are also observed.
- Metabolic health – in addition to weight loss, beneficial changes in metabolic health occur while fasting.
- Brain health
- Cancer prevention
Is intermittent fasting right for me?
According to research, intermittent fasting is safe for most healthy people. The most commonly reported issues with time-restricted eating are hunger, lightheadedness, and cravings.
Intermittent fasting should not be seen as a replacement for following a healthy diet. Because of this, we recommend that only individuals who have been following the Fast Weight Loss 365 program and are eating a well-balanced diet start time-restricted eating.
There are a few instances where we don’t recommend time-restricted eating or any form of intermittent fasting. If you are pregnant or nursing, have an eating disorder or have a history of an eating disorder, fasting is not for you. Additionally, fasting should not be considered if you have uncontrolled diabetes or another condition impacting your glucose metabolism.
If you have well-controlled diabetes or other metabolic conditions, we advise talking to your doctor before starting intermittent fasting.
1. Jamshed H, Beyl RA, Della Manna DL, Yang ES, Ravussin E, Peterson CM. Early Time-Restricted Feeding Improves 24-Hour Glucose Levels and Affects Markers of the Circadian Clock, Aging, and Autophagy in Humans. Nutrients. 2019;11(6):1234. doi:10.3390/nu11061234
2. Anton SD, Lee SA, Donahoo WT, et al. The Effects of Time Restricted Feeding on Overweight, Older Adults: A Pilot Study. Nutrients. 2019;11(7):1500. doi:10.3390/nu11071500
3. Gabel K, Hoddy KK, Haggerty N, et al. Effects of 8-hour time restricted feeding on body weight and metabolic disease risk factors in obese adults: A pilot study. Nutrition and Healthy Aging. 2018;4(4):345-353. doi:10.3233/NHA-170036
4. Gabel K, Hoddy KK, Varady KA. Safety of 8-h time restricted feeding in adults with obesity. Appl Physiol Nutr Metab. 2019;44(1):107-109. doi:10.1139/apnm-2018-0389
5. Wilkinson MJ, Manoogian ENC, Zadourian A, et al. Ten-Hour Time-Restricted Eating Reduces Weight, Blood Pressure, and Atherogenic Lipids in Patients with Metabolic Syndrome. Cell Metabolism. 2020;31(1):92-104.e5. doi:10.1016/j.cmet.2019.11.004
6. Lowe DA, Wu N, Rohdin-Bibby L, et al. Effects of Time-Restricted Eating on Weight Loss and Other Metabolic Parameters in Women and Men With Overweight and Obesity: The TREAT Randomized Clinical Trial. JAMA Internal Medicine. 2020;180(11):1491-1499. doi:10.1001/jamainternmed.2020.4153
7. Przulj D, Ladmore D, Smith KM, Phillips-Waller A, Hajek P. Time restricted eating as a weight loss intervention in adults with obesity. PLOS ONE. 2021;16(1):e0246186. doi:10.1371/journal.pone.0246186
8. Gill S, Panda S. A Smartphone App Reveals Erratic Diurnal Eating Patterns in Humans that Can Be Modulated for Health Benefits. Cell Metabolism. 2015;22(5):789-798. doi:10.1016/j.cmet.2015.09.005