Until recently, fasting was only connected to either a medical requirement before certain clinical tests, or to cultural practices. Now, we know that fasting, particularly intermittent fasting, has a series of health benefits that many are choosing to take advantage of, especially in combination with ketogenic-based diets to boost the benefits of ketosis.
Intermittent fasting is voluntarily going without food for longer periods of time between meals than we are normally accustomed to. Depending on the philosophy, you could avoid eating for 12 hours (let’s say, between 7pm and 7am), or prolong the fasting time even more (between 3pm and 7am the next day, for example) to eat all of your meals within an eight-hour period. Other methods include fasting for a full day once or twice a week, or restricting calories significantly for two days a week.
What are the advantages of intermittent fasting? While we will go into detail about the benefits later on in this article, more and more research is arising on the benefits of intermittent fasting to:
Studies are now even showing how intermittent fasting reduces the risk of several chronic diseases and risk factors, including:
Research on the benefits of intermittent fasting in animals has been carried out for many years, but research on its effect on human health is just beginning to come to light. Below we bring to light some of the science-backed benefits of intermittent fasting for our health.
Intermittent fasting has important beneficial effects on blood sugar levels (blood glucose) and insulin levels, which is good news for people who are at risk of prediabetes and type 2 diabetes (6). Research shows that both intermittent fasting and alternate day fasting help to reduce risk factors that can lead to diabetes, like promoting weight loss to achieve a normal, healthy weight (7). It also allows the pancreas to relax and have a time when it is not producing insulin. This rest period reduces the chances of becoming insulin resistant and diabetic.
Studies performed in rats have demonstrated that intermittent fasting can prevent type 1 diabetic neuropathy from progressing. More studies must be performed, however, until we can see if this benefit is also applicable in humans (8).
When you are fasting, a number of hormonal changes take place- several of which are directly beneficial to your health.
First, as mentioned above, intermittent fasting can significantly reduce insulin levels, thus helping to promote insulin sensitivity. This can help you enter into a ketogenic state and burn excess fat (9).
Second, when you are fasting, human growth hormone levels can increase up to 5 times their normal levels. Like with lowered insulin levels, a boost in HGH helps you lose weight, but it also helps you increase muscle strength (10, 11, 12).
One of the most popular reasons for turning to intermittent fasting is its potential to promote weight loss. Indeed, intermittent fasting can help to boost weight loss to assist you in achieving a healthy body weight (7).
From a practical perspective, it is difficult to restrict calories continuously. For this reason, a study compared the effects on weight loss of continuous energy restriction versus intermittent energy restriction (like intermittent fasting) (13). The researchers concluded that intermittent energy restriction is just as effective as continuous energy restriction for weight loss, and potentially much more realistic to apply in the medium to long term.
In fact, another study with similar results took it a step further; the researchers found that while weight loss results were similar, the individuals that were on an intermittent fasting diet were actually able to preserve muscle mass more effectively than people who constantly restricted calories (14).
The reduced insulin and blood glucose levels that result from intermittent fasting have another benefit: these markers also seem to increase the resistance of the brain to stress (6).
In addition, intermittent fasting also helps to slow brain aging and improve the outcome of brain conditions like Alzheimer’s disease and Parkinson’s disease (21).
How? Researchers at the National Institute of Aging, the Longevity Institute of the University of Southern California, and the John Hopkins Department of Neuroscience conclude that different forms of intermittent fasting help to improve health and counteract disease processes by boosting cell health and DNA repair (21, 15).
While most research on the impact of intermittent fasting on the progression of cancer has been performed on animals, initial results are promising. Researchers carried out a meta-analysis (a review of several high-quality, comparable studies), to determine the effects of different calorie-restricted diets on cancer initiation, progression, and metastasis (16).
The meta-analysis found that the ketogenic diet is effective against cancer in animal experiments, and 62.5% of studies on the effect of intermittent fasting on cancer in animals were also effective. This means that while more studies need to be carried out, the combination of ketogenic diets and intermittent fasting could be effective in helping to slow cancer progression (16).
Oxidative stress is the result of too many free radicals in the body, and too few antioxidants. Free radicals appear in the body as a result of normal processes, environmental factors, and stress. If there are too many free radicals in the body, they can cause inflammation, cell damage, aging and death.
One type of intermittent fasting – alternate-day calorie restriction (ADCR) – was studied for its potential effects on oxidative stress and inflammation. The study revealed that oxidative stress and inflammation declined as a result of intermittent fasting (17).
Early research also demonstrates that intermittent fasting may also lengthen lifespan, as demonstrated by a small study carried out with nematodes (18).
Several studies demonstrate the effects of intermittent fasting on indicators of heart health. Some of these include blood cholesterol and blood pressure. Not only does intermittent fasting help people lose weight, it also helps people lower their risk of coronary heart disease (1). This can result from reduction in LDL cholesterol, blood pressure and fat accumulation close to the organs (19, 20).
Intermittent fasting has numerous health benefits, some of which researchers are only beginning to uncover. While people who follow intermittent fasting should always make sure to get regular checkups, (especially if they have a health condition) well-established and early research have demonstrated the many benefits of intermittent fasting for everything from heart and brain health to weight loss and brain aging.