Intermittent fasting is an eating pattern where you cycle between periods of eating and fasting. There are many different types of intermittent fasting, such as the 16/8 or 5:2 methods. Numerous studies show that it can have powerful benefits for your body and brain.
Here are the top 5 evidence-based health benefits of intermittent fasting:
1. Intermittent fasting changes the function of cells, genes and hormones
When you don’t eat for a while, several things happen in your body. For example, your body initiates important cellular repair processes and changes hormone levels to make stored body fat more accessible. Some of the changes that occur in your body during fasting, include:
- Insulin levels: Blood levels of insulin drop significantly, which facilitates fat burning.
- Human growth hormone: The blood levels of growth hormone may increase. Higher levels of this hormone facilitate fat burning and muscle gain, and have numerous other benefits.
- Cellular repair: The body induces important cellular repair processes, such as removing waste material from cells.
- Gene expression: There are beneficial changes in several genes and molecules related to longevity and protection against disease.
2. Intermittent fasting can help you lose weight and belly fat
Many of those who try intermittent fasting are doing it in order to lose weight. Generally speaking, intermittent fasting will make you eat fewer meals. Unless if you compensate by eating much more during the other meals, you will end up taking in fewer calories.
Additionally, intermittent fasting enhances hormone function to facilitate weight loss. Lower insulin levels, higher growth hormone levels and increased amounts of norepinephrine (noradrenaline) all increase the breakdown of body fat and facilitate its use for energy. For this reason, short-term fasting actually increases your metabolic rate by 3.6-14%, helping you burn even more calories.
In other words, intermittent fasting works on both sides of the calorie equation. It boosts your metabolic rate (increases calories out) and reduces the amount of food you eat (reduces calories in).
According to a 2014 review of the scientific literature, intermittent fasting can cause weight loss of 3-8% over 3-24 weeks (12). This is a huge amount. The people also lost 4-7% of their waist circumference, which indicates that they lost lots of belly fat, the harmful fat in the abdominal cavity that causes disease. One review study also showed that intermittent fasting caused less muscle loss than continuous calorie restriction.
All things considered, intermittent fasting can be an incredibly powerful weight loss tool.
3. Intermittent fasting can reduce insulin resistance, lowering your risk of Type 2 diabetes
Type 2 diabetes has become incredibly common in recent decades. Its main feature is high blood sugar levels in the context of insulin resistance. Anything that reduces insulin resistance should help lower blood sugar levels and protect against Type 2 diabetes.
Interestingly, intermittent fasting has been shown to have major benefits for insulin resistance and lead to an impressive reduction in blood sugar levels (12).
In human studies on intermittent fasting, fasting blood sugar has been reduced by 3-6%, while fasting insulin has been reduced by 20-31% (12).
One study in diabetic rats also showed that intermittent fasting protected against kidney damage, one of the most severe complications of diabetes.
What this implies, is that intermittent fasting may be highly protective for people who are at risk of developing Type 2 diabetes.
4. Intermittent fasting can reduce oxidative stress and inflammation in the body
Oxidative stress is one of the steps towards aging and many chronic diseases. It involves unstable molecules called free radicals, which react with other important molecules (like protein and DNA) and damage them. Several studies show that intermittent fasting may enhance the body’s resistance to oxidative stress.
Additionally, studies show that intermittent fasting can help fight inflammation, another key driver of all sorts of common diseases.
5. Intermittent fasting may be beneficial for heart health
Heart disease is currently the world’s biggest killer.
It is known that various health markers (so-called “risk factors”) are associated with either an increased or decreased risk of heart disease.
Intermittent fasting has been shown to improve numerous different risk factors, including blood pressure, total and LDL cholesterol, blood triglycerides, inflammatory markers and blood sugar levels. However, a lot of this is based on animal studies. The effects on heart health need to be studied a lot further in humans before recommendations can be made.
We give our clients the option to try intermittent fasting in weeks 5 and 6 of the FIT IN SIX programme. Personally, when I did this, I thought it would be harder than it actually was. The idea of it made it worse than the actual overall experience. The first few days were hard getting used to this new way of eating but I started to feel better (especially around my stomach) after just a couple of days. After the two weeks, I had lost almost 10cm off my stomach line!! My clients have all found similar results which shows it really does work.