The Truth about Intermittent Fasting (March 2020)
If I had a coin for each time a new diet trend hit the scene, I would have a lot of change in my pocket. Intermittent fasting is a trend that promises longer life, improved health, decreased inflammation in the body and full-body transformation.
The practice of intermittent fasting involves significant caloric reduction with periods of fasting anywhere from a 12-hour period (or longer), restricted eating times (following a meal plan with specific times), and periods of what is defined as “normal” eating, which still involves limiting carbohydrate intake. As a nutrition therapist that specializes in body image issues, eating disorders and medical conditions, red flags stand out when any type of program involves restriction, food rules, and cutting out or back on any specific food group.
The idea behind this recent trend is that a person’s body will begin to burn fat after they are in a place of starvation, approximately 12-24 hours after their last feeding time. The belief is that bodily change will lead to improved overall wellbeing.
The majority of studies done on intermittent fasting have only been done on animals. Yes, these results show it slows down their aging process and reduces cancer risk, but, we are very different from rats. The animal studies have shown that restricting the caloric intake can have benefits and it is hypothesized for humans that this period of fasting can repair cells, improve immune response, and improve lipid panels to name a few potential benefits. Studies have yet to show that the same results would occur in humans.
With that said, studies also indicate that it is very likely a person will overconsume, binge, and/or be consumed with food on non-fasting days Researchers have also seen that, over a 12-month study, 38% of the participants in intermittent fasting dropped out due to feeling deprived, wanting to reward themselves using food, and, shocker, being hungry! Our appetite hormones and the hunger center of the brain are constantly fixated on food when we are not only deprived of it, but told when to eat, how much to eat, and given restrictive food options. The bottom line is that our cortisol level, also known as the stress hormone, will increase due to the lack of fuel.
It is also common that a person engaging in intermittent fasting will be dehydrated due to lack of fluid intake, have sleep patterns interrupted and be tired, hungry, and constantly focused on food. If the neurotransmitters in our brain dopamine and serotonin are low, our anxiety and depression levels can increase. Certainly, when we don’t eat, a person could become anxious and depressed as they are concerned about a specific food, quantity or anything pertaining to the rules they have been prescribed. When we eat, our anxiety levels are less than if we restrict, or fast.
Intermittent fasting, in fact, does the opposite of what people intend to do when engaging in it. By not eating for extended periods of time, the rate of metabolism actually decreases.
I would not suggest this dietary regimen to anyone. This includes people who do not have medical issues as well as those who do not have eating disorders, as it is likely they will have disordered eating and thinking after following this trend. At this present time, the research has not been convincing for me to endorse this eating plan.
- Trepanowski, J., et al. (2017). Metabolically Health Obese Adults. JAMA Internal Medicine, 930-938.
- Collier, R. (2013). Intermittent fasting: the science of going without. Canadian Medical Association Journal, 363-364.
- Unknown (2019). Not so fast: pros and cons of the newest diet trend. Harvard Health.