What Is Intermittent Fasting (IF)?
Intermittent fasting (IF) is an eating pattern that cycles between periods of fasting and eating.
It doesn’t specify which foods you should eat but rather when you should eat them.
In this respect, it’s not a diet in the conventional sense but more accurately described as an eating pattern.
Common intermittent fasting methods involve daily 16-hour fasts or fasting for 24 hours, twice per week.
Fasting has been a practice throughout human evolution. Ancient hunter-gatherers didn't have supermarkets, refrigerators or food available year-round. Sometimes they couldn't find anything to eat.
As a result, humans evolved to be able to function without food for extended periods of time.
In fact, fasting from time to time is more natural than always eating 3–4 (or more) meals per day.
Fasting is also often done for religious or spiritual reasons.
Intermittent fasting (IF) is an eating pattern that cycles between periods of fasting and eating. It’s currently very popular in the health and fitness community.
How It Affects Your Cells and Hormones
When you fast, several things happen in your body on the cellular and molecular level.
For example, your body adjusts hormone levels to make stored body fat more accessible.
Your cells also initiate important repair processes and change the expression of genes.
Here are some changes that occur in your body when you fast:
Human Growth Hormone (HGH): The levels of growth hormone skyrocket, increasing as much as 5-fold. This has benefits for fat loss and muscle gain, to name a few.
Insulin: Insulin sensitivity improves and levels of insulin drop dramatically. Lower insulin levels make stored body fat more accessible
Cellular repair: When fasted, your cells initiate cellular repair processes. This includes autophagy, where cells digest and remove old and dysfunctional proteins that build up inside cells
Gene expression: There are changes in the function of genes related to longevity and protection against disease These changes in hormone levels, cell function and gene expression are responsible for the health benefits of intermittent fasting.
When you fast, human growth hormone levels go up and insulin levels go down. Your body’s cells also change the expression of genes and initiate important cellular repair processes.
A Very Powerful Weight Loss Tool
Weight loss is the most common reason for people to try intermittent fasting
By making you eat fewer meals, intermittent fasting can lead to an automatic reduction in calorie intake.
Additionally, intermittent fasting changes hormone levels to facilitate weight loss.
In addition to lowering insulin and increasing growth hormone levels, it increases the release of the fat burning hormone norepinephrine (noradrenaline).
Because of these changes in hormones, short-term fasting may increase your metabolic rate by 3.6–14%
By helping you eat fewer and burn more calories, intermittent fasting causes weight loss by changing both sides of the calorie equation.
Studies show that intermittent fasting can be a very powerful weight loss tool.
A 2014 review study found that this eating pattern can cause 3–8% weight loss over 3–24 weeks, which is a significant amount, compared to most weight loss studies.
According to the same study, people also lost 4–7% of their waist circumference, indicating a significant loss of harmful belly fat that builds up around your organs and causes disease.
Another study showed that intermittent fasting causes less muscle loss than the more standard method of continuous calorie restriction.
However, keep in mind that the main reason for its success is that intermittent fasting helps you eat fewer calories overall. If you binge and eat massive amounts during your eating periods, you may not lose any weight at all.
Intermittent fasting may slightly boost metabolism while helping you eat fewer calories. It’s a very effective way to lose weight and belly fat.
Many studies have been done on intermittent fasting, in both animals and humans.
These studies have shown that it can have powerful benefits for weight control and the health of your body and brain. It may even help you live longer.
Here are the main health benefits of intermittent fasting:
Weight loss: As mentioned above, intermittent fasting can help you lose weight and belly fat, without having to consciously restrict calories.
Insulin resistance: Intermittent fasting can reduce insulin resistance, lowering blood sugar by 3–6% and fasting insulin levels by 20–31%, which should protect against type 2 diabetes. Inflammation: Some studies show reductions in markers of inflammation, a key driver of many chronic diseases.
Heart health: Intermittent fasting may reduce “bad” LDL cholesterol, blood triglycerides, inflammatory markers, blood sugar and insulin resistance — all risk factors for heart disease. Cancer: Animal studies suggest that intermittent fasting may prevent cancer.
Brain health: Intermittent fasting increases the brain hormone BDNF and may aid the growth of new nerve cells. It may also protect against Alzheimer’s disease.
Anti-aging: Intermittent fasting can extend lifespan in rats. Studies showed that fasted rats lived 36–83% longer.
Keep in mind that research is still in its early stages. Many of the studies were small, short-term or conducted in animals. Many questions have yet to be answered in higher quality human studies.
Intermittent fasting can have many benefits for your body and brain. It can cause weight loss and may reduce your risk of type 2 diabetes, heart disease and cancer. It may also help you live longer.
Makes Your Healthy Lifestyle Simpler
Eating healthy is simple, but it can be incredibly hard to maintain.
One of the main obstacles is all the work required to plan for and cook healthy meals.
Intermittent fasting can make things easier, as you don't need to plan, cook or clean up after as many meals as before.
For this reason, intermittent fasting is very popular among the life-hacking crowd, as it improves your health while simplifying your life at the same time.
One of the major benefits of intermittent fasting is that it makes healthy eating simpler. There are fewer meals you need to prepare, cook and clean up after.
Who Should Be Careful Or Avoid It?
Intermittent fasting is certainly not for everyone.
If you’re underweight or have a history of eating disorders, you should not fast without consulting with a health professional first.
In these cases, it can be downright harmful.
Safety and Side Effects
Hunger is the main side effect of intermittent fasting.
You may also feel weak and your brain may not perform as well as you're used to.