Intermittent fasting has gained a lot of popularity in recent years. Although weight-loss appears to be the primary driver of this, there is growing interest in IF’s other health benefits as well.
Although it’s often referred to as a diet, IF is more correctly understood as an eating pattern that could activate certain benefits for practitioners, such as weight loss, if done correctly.
So are there other health benefits associated with this lifestyle? Actually, yes. There are numerous science-backed health benefits of intermittent fasting that go beyond mere weight loss. These include mental health, brain health, reduced inflammation, and cell repair, to name but a few.
In the subsequent tiles we’ll take a closer look at some of these evidence-backed benefits of intermittent fasting.
Weight Loss and Visceral Fat
The main reason why many people choose to do intermittent fasting is for weight loss . When practiced over time, the secret to the weight loss success of intermittent fasting lies in the fact that you eat fewer meals, which results in a lower calorie intake (assuming you don’t overindulge in the feeding window).
Intermittent fasting also enhances hormone function which facilitates weight loss. The breakdown of body fat to use as energy is increased due to a decrease in insulin, and an increase in two key hormones: human growth hormone (HGH), and norepinephrine (noradrenaline). The presence of HGH and noradrenaline in the body increases metabolic rate, which results in more calories that are burnt .
According to a 2014 study, intermittent fasting could cause weight loss of 3-8% within 3-24 weeks, which is more than many diets . The same study also found that visceral fat was also markedly reduced.
During a fast, there are a lot of things that happen in your body. For one, the hormone levels in your body change to make your stored body fat more accessible and to initiate a cellular repair process.
Many of the health benefits of intermittent fasting are related to changes in hormones, the functioning of cells, and gene expression.
We’ve already covered how an increase in HGH and noradrenaline, along with a drop in insulin helps the body to burn fat [4-6]. Besides that, the hunger hormone, ghrelin, decreases, causing your appetite to be suppressed.
On a cellular level, the cellular repair process of autophagy is activated. We explain more about autophagy later in this tile. One study also found beneficial changes in several genes and molecules related to longevity and protection against disease .
Increased insulin sensitivity
To understand how and why fasting can be effective for people with diabetes, it will be helpful to explain what type 2 diabetes is. People with Type 2 diabetes typically have chronically elevated levels of blood glucose along with a decreased sensitivity to insulin. While genetic predisposition can increase the risk of Type 2 Diabetes, lifestyle factors such as diet, exercise, sleep and chronic stress can increase the likelihood of developing the disease.
In a 2014 study on intermittent fasting, individuals with prediabetes that fasted had their fasting blood sugar reduced by 3–6% over the course of 8–12 weeks. Fasting insulin is reduced by 20–31% . This suggests that intermittent fasting may be beneficial for people who are at risk of developing type 2 diabetes.
Reduced oxidative stress and inflammation
Oxidative stress in the body occurs when unstable molecules called free radicals, which react with other important molecules, such as protein and DNA, and damage them , leading to accelerated ageing and increased risk of various chronic diseases.
Several studies have shown that intermittent fasting could enhance the body’s response to oxidative stress [11, 12].
Other studies show that intermittent fasting could be helpful in fighting inflammation, a condition that can lead to various diseases such as diabetes, multiple sclerosis, and inflammatory bowel syndrome [11, 13, 14].
Intermittent fasting may also influence the gut microbiome: the complex and diverse microbial community that resides in the intestinal tract and whose health plays a significant role in affecting our immunity, weight, stress, and overall well-being.
If the gut microbiome is out of balance, it could result in numerous negative effects, for example, weight gain and obesity. Intermittent fasting could play a role in restoring your gut microbiome by giving your gut a rest. Research shows that it could help prevent inflammatory toxins from leaking into your bloodstream through your gut lining, as is the case with individuals diagnosed with leaky gut syndrome (ulcerative colitis) .
According to the World Health Organization, heart disease is number one on the list of the top causes of death worldwide . Intermittent fasting may be beneficial for heart health. It has been shown to improve several risk factors, such as blood sugar levels, blood pressure, blood triglycerides, cholesterol, and inflammation markers in the body.
It should, however, be noted that most of these studies have been conducted on animals and that the effect of fasting should be studied more in-depth in humans before recommendations can be made.
However, recent studies on humans on this topic have produced promising results. Although the exact mechanisms remain unclear, intermittent fasting appears to positively impact multiple cardiovascular risk factors including obesity, hypertension, dyslipidemia, and diabetes .
Furthermore, intermittent fasting has been associated with improved outcomes after a cardiac event .
After a full-day fast, your body starts to repair itself through a magical process is called autophagy. The term is Greek for “self-eating,” and that’s exactly what happens. During autophagy, your cells break down and metabolize broken and dysfunctional proteins that build up over time. A positive health benefit of autophagy is a reduction in inflammation which can be harmful when left unchecked.
Besides fighting inflammation, autophagy has a set of health benefits. Autophagy declines naturally as you age, which is connected to a variety of diseases. It is therefore, very important to ‘help’ this process along as much as possible, and especially as you start to age. Studies have shown that fasting could combat general age-related decline and increase longevity . Autophagy also clears out damaged and misfolded proteins which have been linked to Alzheimer’s disease . Early research even suggests that fasting-related autophagy may help kill cancer cells .
To enjoy the benefits of autophagy and its anti-ageing or anti-inflammatory benefits, a 24-hour fast is a good option.
Fasting and Cancer
Fasting or diets that mimic fasting have been reported to have several beneficial effects on metabolism that may lead to a reduced risk of cancer .
A systematic review that included 8 studies of intermittent fasting ranging from 24 to 72 hours found that 63% of the studies inhibited tumor growth; the others found no significant difference in comparison with animals that were on a normal diet .
Early studies on humans also show similar results when it comes to intermittent fasting and cancer [23, 24]. This area of research is in its infancy and more studies should be conducted before a proper conclusion can be drawn. Preliminary results are, however, promising.
In the domain of cancer treatment, fasting or intermittent fasting has been proven, in several studies, to help deal with the toxicity of chemotherapy [25-28]. Patients who fasted before and/or after chemotherapy found that the adverse effects of chemotherapy were lower compared to when they didn’t fast [25, 26].
Brain Benefits and Neurodegenerative Diseases
Fasting increases levels of brain-derived neurotrophic factor (BDNF) – a protein that your brain produces to protect existing brain cells. BDNF also supports the growth of new neurons, enhances long-term memory, learning , and boosts mood .
Studies have also proven that intermittent fasting improves mitochondrial function, which plays a central role in brain ageing and neurodegenerative diseases, such as Alzheimer’s disease, Parkinson’s disease, and Huntington’s disease.
Alzheimer’s disease is the world’s most common neurodegenerative disease. Currently, there is no known cure for this disease, so prevention is crucial. In a series of case reports, a lifestyle intervention that included daily short-term fasts was able to significantly improve Alzheimer’s symptoms in 9 out of 10 people .