Intermittent fasting (IM) is becoming more and more trendy, publicized and researched. This diet “pattern” boasts results like weight loss, longevity, clearer thinking and increased insulin sensitivity. I am going to spend my next two newsletter articles further explaining what intermittent fasting is, how it works and who might benefit from trying this type of lifestyle.
Fasting is nothing new. Fasting is documented and practiced by many different religious groups. Hippocrates even wrote, “To eat when you are sick, is to feed your illness”, and “instead of using medicine, better fast today.” If you dive deeper into the history of intermittent fasting, it is thought that during the times of hunters and gatherers, plentiful meals were not offered three to six times daily. In order to survive, food was used sparingly and when available. I can imagine there were many days when food was not found or available. Can we credit the weight gain and increased disease rate among humans over the last one hundred years to when we eat instead of what we eat? Interesting.
There are three varieties of intermittent fasting:
The 16/8 Method involves eating during an eight-hour window within a twenty four hour cycle. For instance, breakfast is skipped and eating takes place between the hours of 11am and 7 pm.
The Eat-Stop-Eat method involves fasting for twenty-four hours straight, one to two times weekly.
The 5:2 Method includes almost fasting for two non-consecutive days each week. During “fasting” days only 500-600 calories are consumed.
Keep in mind when not fasting, there are no restrictions to what can be consumed. Recommendations are to “eat sensibly.” All publications note that non-fasting days cannot be used to freely overeat. If non-fasting days are used to eat large quantities of high calorie, low nutrient foods, weight loss and metabolic benefits are lost. Some common sense has to be used when choosing what to eat, as well as the quality of food consumed. Indulging on a limited basis is just fine.
The science behind intermittent fasting is strongly related to stress and how the body adapts to stress. A journal article from the Canadian Medical Association Journal states recent intermittent fasting research is showing promising results in the “improvement of biomarkers of disease, reduction of oxidative stress and preservation of learning and memory functions.” Some studies are saying intermittent fasting may help decrease the risk of neurodegenerative diseases like Alzheimer’s and Parkinson’s, prevent cancer, and even possibly prolong life.
One theory as to why these improvements are found revolves around stress. When the body is fasting, it is under mild stress and over time the body adapts and becomes accustomed to this stress. Because the body has become “stronger” due to this long term stress, it has a better ability to fight off the much more significant stress associated with disease. The article explains that the stress of intermittent fasting can be thought of as exercise. It is stressful to exercise, but when the body is given proper rest and recovery, it has the ability to adapt, heal and continue to progress. As with exercise, intermittent fasting should be slowly integrated into a lifestyle.
Weight loss and the maintenance of a low BMI are also associated with a decreased risk of cancer. Many different women struggle with weight loss. Because consumption is restricted, calorie intake would naturally be reduced. In a normal, healthy adult, this theory may be true: if calorie consumption in reduced, weight loss will occur. (If you are struggling with weight loss, please schedule a nutritional consultation to discuss your symptoms.)
Intermittent fasting, calorie restriction or “undernutrition without malnutrition”, has been one of the only ways research has found mice with cancer to prolong survival. As noted in the Prostate Cancer and Prostatic Diseases 2010 journal article, if mice are given the option to eat unlimited amounts of food on non-fasting days, or overcompensate, benefits regarding survival and tumor growth were lost. Decreased energy intake is needed to achieve the full benefits of intermittent fasting.
Fasting challenges the brain. As the brain continues to be stressed, over time it builds up “strength” and is able to adapt to the stressors of disease. Mark Mattson, a professor of neuroscience at Johns Hopkins School of Medicine believes that IM helps neural connections and reduces the build of amyloid plaques, which are proteins found in abundance in people with Alzheimer’s. When thinking of the natural progression of humans, we know that there were times of hunger. Food was not constantly available. It was necessary for the brain to function at its best, even during times of fast.
Intermittent fasting has also been shown to increase insulin sensitivity because it allows glycogen stores to be depleted. Once all the glycogen has been used that is stored in the liver, the body starts producing ketone bodies, which are then used by neurons in the brain. Low insulin levels are also associated with longer life spans. It should also be recognized that exercise has the same positive effects on the brain and insulin levels as intermittent fasting.
Intermittent fasting is very complex and not recommended for everyone. Next month we will discuss who is a candidate for intermittent fasting as well as how intermittent fasting can be used incorrectly.
If you have questions regarding intermittent fasting or would like to learn how to integrate intermittent fasting into your current lifestyle, please call and schedule a nutritional consultation.
Leslie Rusch-Bayer