By Helaine Krasner, RDN
There has been a lot of talk lately about Intermittent Fasting (IF) and a related term, Time Restricted Feeding (TRF). IF most commonly applies to an eating style where food intake is restricted on certain days of the week and unrestricted on others. Two common examples are alternate day fasting and the 5:2 diet, which involves energy restriction for two days per week with no restriction for the other five. TRF is a similar concept where you are only permitted to eat between certain times and abstain from eating the rest of the day.
There is research to support the effectiveness of both strategies for weight loss and improvement of health markers such as blood sugar, blood pressure, and cholesterol. Much research to date has been done on rats, but there have recently been human studies that back up the benefits seen in animals.
Years ago the typical dietary pattern included three meals per day and perhaps one or two snacks. Nowadays, due to the availability of food items at virtually every location, all day snacking and late night eating have become commonplace for many people. This behavior is in conflict with human biology. Humans have evolved to be in sync with a circadian rhythm of daytime eating and nighttime sleeping. Disruption of this cycle contributes to health problems including being overweight and obesity.
It is important for the body to have time to perform growth and repair in addition to other body processes that don’t typically occur when the body is involved in digestion and absorption of nutrients. The hormone insulin is involved in energy storage (energy=calories stored as fat) and is released when we eat to help our body move sugar into our cells. When insulin levels decline our cells can release stored energy. If we eat too frequently and keep insulin levels up it promotes weight gain. IF gives the body the opportunity to burn stored energy (aka fat), promoting weight loss.
Although both IF and TRF are safe and effective, they are not superior to other diets and may be just as difficult to follow.
Tips for the Attaining the Benefits of Intermittent Fasting
- Avoid excessive snacking or grazing on small amounts of food throughout the day.
- Consume nutritious snacks when needed to fill long gaps between meals.
- Consider a simple form of intermittent fasting by limiting eating times to 8-12 hours per day.
- Avoid the tendency to eat at night by adhering to a structured daytime eating pattern.
Tello, M. Intermittent fasting: surprise update. Harvard Health blog. June 29, 2018. https://www.health.harvard.edu/blog/intermittent-fasting-surprising-update-2018062914156
Patterson RE, Laughlin GA, Sears DD, et al. Intermittent fasting and human metabolic health. J Acad Nutr Diet. 2015;115(8):1203-1212. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4516560/
Helaine Krasner is a Registered Dietitian Nutritionist who takes great pride in helping our Bariatric and Medical Weight Management patients achieve their health and weight loss goals.