What is Intermittent Fasting
Intermittent Fasting (IF) has been in the spotlight for years as a popular and effective method for losing weight. It is also increasingly gaining recognition as a way to improve overall health, vitality, and longevity.
The “intermittent” aspect of IF refers to alternating periods of fasting and periods of eating. We are generally well-adapted to going without food for short periods of time because our ancestors did not always have a ready supply, and these fasting periods naturally trigger numerous health benefits.
There are several variations in the method of IF that can be used to meet different preferences, goals, or physiological needs. Some of the methods are calorie-restricted, while others are not, with normal caloric intake at restricted times.
These are the most common variations of IF:
16/8 Method: The fasting window is 16 hours, and the eating window is 8. The fast usually begins after dinner and ends with a late breakfast or lunch the following morning.
5/2 Method: Eating normally for five days and restricting calories to 500-600 on two days. The two days should be non-consecutive and spaced out throughout the week.
Alternate-Day Fasting: Alternate normal calorie days and fasting days. Fasting days can be fully without food or low 500-calorie days.
Eat, Stop, Eat: One or two fasting days per week. The fasting window is 24 hours and is usually from the end of dinner to the beginning of dinner the following day.
The Warrior Diet: Most of the day is spent in a fasting state, with a 4-hour window for one substantial meal in the evening. Some amount of light snacks, usually fruits and vegetables are allowed during fasting times.
Health Benefits of Intermittent Fasting
There is a growing body of research that suggests IF can be an incredibly effective way to lose weight, improve overall health, and resist chronic illness. These beneficial changes happen when our bodies run out of glucose as an energy source and begin using fat stores.
After a meal, our body breaks down carbohydrates into glucose for fuel. When it runs out of free glucose, it turns to glucose stored in the form of glycogen in the liver. When glycogen stores are depleted, it turns to fat stores. This releases fatty acids that are converted to ketone bodies, which are another source of fuel for cells.
The transition from using glucose to fat is gradual and begins about 10-16 hours after the last meal. At this point, the body begins entering light ketosis (using ketones as fuel) and continues to a full state of ketosis if the fasting period is long enough. The health benefits of using ketones instead of glucose are the reason why many people follow the keto diet. IF mimics many of those benefits.
The fasting state is natural for us even though most people do not fast regularly. Our modern times have allowed us to enjoy three meals per day, but our ancestors hardly ate this way. For most of human history, people had to endure periods of fasting due to lack of food. Not only are our bodies adapted to periods of not eating, there is more and more evidence showing that it is the a more optimal state.
Given modern research and developments in health and fitness, we now have the option of harnessing these healing changes once we learn how to do so effectively. Some of the most studied benefits of IF are:
Promotes weight loss: In addition to the obvious benefits of restricted caloric intact, IF has been shown to optimize weight loss by increasing metabolism. Also, because the body switches to fat-burning during fasting periods, IF has been shown to better target areas of problematic fat accumulation, such as abdominal fat and fatty liver.
Increases insulin sensitivity: Increases insulin sensitivity in those with insulin resistance and improves blood glucose balance.
Improves cardiovascular health: Studies show that IF lowers systolic blood pressure, heart rate, and blood levels of triglycerides and LDL cholesterol.
Decreases inflammation: IF decreases inflammatory markers.
Improves brain health: Improves cognitive performance and memory.
Promotes cellular renewal: Triggers the process of autophagy, which recycles old or damaged cells in the body, getting rid of built-up waste and cellular debris, improving the metabolic functions of cells, and reducing oxidative stress.
Triggers adaptive cellular stress response: Enhances cellular ability to resist injury and disease.
Naturally increases Human Growth Hormone: (HGH). HGH has many important functions in the body and plays a role in longevity. However, the production of this hormone subsides as we age, and IF is a natural way to boost it.
Is Fasting for Everyone?
In short, no. While many people can enjoy the benefits of IF, there are some cases where fasting can induce unfavorable changes. Fasting may not be right for you if you experience the following:
- Underlying hormonal imbalances or thyroid issues
- Significant stress or insomnia
- Low blood sugar or diabetes (diabetes patients may be able to practice IF under the supervision of their physician)
- Gallstones or gallbladder issues
- Women who are trying to conceive
It is best to consult a healthcare professional before starting IF to determine if it is right for you and find the most suitable approach.
Is Intermittent Fasting a Diet?
When people think of “going on a diet” it usually means making short-term changes to achieve a goal, such as weight loss. IF can be used this way, but its value is harnessed to the fullest capacity when it is practiced long term as a lifestyle. More and more research supports that over the long-term, IF can nourish and optimize your health, promote longevity and decrease chronic illnesses.
If we consider the term “diet” in the broader sense of food choices, whether it’s Mediterranean, paleo, plant-based, vegetarian, keto, or one of the modern variations, IF can be used in conjunction with and to enhance the benefits of any of these.
Summary of Intermittent Fasting
- IF alternates fasting and eating periods, and triggers burning fat for fuel in the fasting state. Fasting periods range between 12 and 24 hours.
- Studies on IF are showing significant health benefits, including weight loss, increased insulin sensitivity, cardiovascular and brain health, and reduction in inflammation.
- It is important to know if you have any conditions that can make fasting not right for you.
- IF works best as a lifestyle choice and can complement other diet plans.