Intermittent fasting (IF) has been around for years, with various formats that people can use to help with weight loss, disease prevention (or reversal), inflammation reduction, and digestion improvement.
Intermittent fasting is not always a caloric reduction method of weight loss. In some formats, people do restrict their calories. In others, it is more about timing meals, with no specifications about what foods to eat. However, the foods people eat can help or hinder their fasting efforts.
In prehistoric times, people relied on hunting and gathering skills to survive. They often went for long periods without food. That is one of the factors behind certain types of intermittent fasting.
Today’s fast food, packaged snacks, and frozen meals have made eating or grazing easier all day. Portions are super-sized. We spend more time in front of the television or computer and less outdoors and engaging in physical activity.
These “modern” changes can have detrimental effects on the body. Intermittent fasting changes eating habits to “mindful” eating, providing many health and wellness benefits.
Of course, not everyone should try intermittent fasting, and as with making any dietary changes, speaking with your doctor first is advised, especially if you have underlying health issues or are taking medications.
What Is Intermittent Fasting?
Instead of focusing on specific foods, intermittent fasting focuses on when you eat. You eat only during those hours by choosing a specific food consumption schedule.
Some plans alternate timing schedules during the week; others have one set of times you follow.
Below, we look at the 9 most common types of intermittent fasting:
- Alternate Day Fasting: Here you have two options, switching between one day of eating normally and the next choosing one of the ways below:
- Consuming only 500 calories on alternate days
- Doing a total 24-hour fast on alternate days
- One Meal Per Day: In this method, you consume only one meal a few days a week. You can alternate this with other methods of intermittent fasting.
- Overnight Fasting: Many people do this without realizing it, as you fast for 12 hours overnight and consume all food during a 12-hour window. Since you should sleep for 8 hours each night, that leaves two hours in the evening and two hours in the morning to avoid food.
- Spontaneous Meal Skipping: Unlike other set options, spontaneous meal skipping allows you to fast based on whenever your body is not hungry. There is no schedule to follow.
- 5:2 Method of Twice a Week Fasting: With this option, you eat normally for 5 days, then cut calories to 500 to 600 the next two days before repeating.
- Time Restricted Fasting: With time-restricted fasting, you set the method you want based on an eating window, with the smaller number below being the time frame to consume food:
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- 20/4
- 18/6
- 16/8
- 14/10
- 24-Hour Fasting: 24-hour fasts should only be done once or twice weekly. Whatever time you complete eating the day before is the time you start eating the following day. With 24-fasts, the ketone levels rise to help the body burn stored fat.
- 36-Hour Fasting: Like the 24-hour fast, you go 36 hours without eating anything in this method. Breaking this lengthy fast should be with a small, high-protein meal that is easy to digest. Working out during an extended fast is not recommended.
Benefits of Intermittent Fasting
Intermittent fasting has been shown to have numerous health and wellness benefits for adults. However, in many areas, studies have shown that while IF produces most of these results, they are generally the same results associated with weight loss from other diets, including a low-carb diet.
The difference between these diets is that some people find IF easier to follow than food or caloric-restricted diets.
We look at some of the most researched areas below:
- Lose weight and fat
With intermittent fasting, you typically eat less each week, reducing caloric intake, which translates to weight loss. Intermittent fasting helps boost human growth hormone (HGH) production, which stimulates metabolism and lowers insulin levels so the body utilizes and breaks down fat for energy. While IF may not improve weight loss over other diets, it can benefit people who do not like to follow special diets requiring extensive meal planning.
- Lower the risk of type 2 diabetes
According to studies, IF helps lower insulin levels and insulin resistance and increase insulin sensitivity. Because IF is often used to help with weight loss, it reduces the risk of developing type 2 diabetes. Anyone with diabetes or other medical conditions should speak with their doctor before trying intermittent fasting.
- Improve heart health
Intermittent fasting helps improve metabolic parameters, such as lowering LDL (bad) and total cholesterol and triglyceride levels and increasing HDL (good) cholesterol. IF can improve resting heart rate and blood pressure, with a 2020 study showing that intermittent fasting brought more significant reductions in systolic blood pressure than a diet that did not utilize defined eating times. Lowering LDL cholesterol helps reduce the risk of cardiovascular disease.
- Good for brain health
Studies have shown that intermittent fasting may boost verbal memory and help guard against developing neurological disorders. IF stimulates HGH production, which has many neuroprotective benefits for the brain. Intermittent fasting also helps decrease oxidative stress and increase brain-derived neurotrophic factor (BDNF) levels that can protect against depression and other brain issues.
- Can prevent neurodegenerative disease
Fasting for 18 hours or more can induce autophagy, a process that leads to cellular breakdown and destruction of abnormal, damaged, or old cytoplasm proteins. The body then uses those products to support cellular functions. Autophagy increases may help protect against neurodegenerative diseases such as Parkinson’s disease and Alzheimer’s disease. The increase in HGH helps reduce tissue damage while supporting cellular regeneration and tissue repair.
- Improve lifestyle and habits
Intermittent fasting simplifies life for many people as they do not need to worry about meal prep for specific diets. You do not have to adhere to a low-carb, high-protein, high-fat, or any other type of diet. Eating only during the diet’s parameters frees up time preparing special meals.
Because you are limited to eating during certain times, you are likely more mindful of what you eat. Many IF methods restrict late-night eating when it is more likely to consume unhealthy snack foods.
- Help digestive system
Late-night eating has been suggested as a cause of disturbance in the body’s circadian rhythm and energy balance. Circadian rhythms influence insulin secretion and sensitivity, metabolism, and HGH production. IF can help improve metabolism and gut microbiome for improved digestion.
What Effects Does Intermittent Fasting Have?
- Hormonal and cellular changes
During times of non-eating, crucial changes occur in the body. Insulin levels decline because the hormone is not needed since food is absent. After the body uses any available glucose, it turns to its fat stores for energy in a process called ketosis. Allowing the body to rest during intermittent fasting helps detoxify and remove damaged cells to help slow aging. The body adjusts various hormone levels to increase the accessibility of stored fat.
How does intermittent fasting increase HGH? Fasting provides a spike in morning HGH secretion. When the body thinks it is “starving,” it increases HGH production to force the usage of stored fat. Intermittent fasting stops the process of consistently feeding cortisol, the stress hormone. As cortisol levels climb, HGH levels go down. When you take a break from eating, the body does not need insulin to manage glucose levels. If you constantly consume small meals throughout the day, insulin production continues and interferes with natural metabolic processes.
IF increases human growth hormone production, which stimulates cellular regeneration and repair. HGH helps increase lean muscle mass and bone mineral density. Since muscle burns calories at a higher rate than fat, weight loss is further increased.
- Gene expression
Almost 40 percent of the genes in the hypothalamus, adrenal gland, and pancreas may be affected by time-restricted eating. The body’s cells respond to a decline in nutrients by turning off or on various genes that can influence inflammation, brain functions, longevity, and health.
- Fight inflammation
During periods of IF, pro-inflammatory markers may decrease, according to a study on participants who fasted during Ramadan. Body weight, fat, and blood pressure levels were also lower. During Ramadan, participants fast from sunrise to sunset, eating only at night. Inflammation is a contributing factor to many diseases.
- Improve metabolism and prevent cancer
Intermittent fasting increases metabolic rate, improving fat burning and decreasing muscle loss. While more research is needed, several studies have shown that IF may help slow cancer cell ability to spread. One study of women showed that decreasing nighttime calories and increasing nocturnal fasting times might reduce inflammation and breast cancer risk. Fasting may help reduce some chemotherapy side effects.
Conclusion
Intermittent fasting has many benefits for the adult body, including hormone production and weight loss. However, it should be started after speaking with your doctor. You can select the method that best fits your lifestyle or experiment with different styles until you find the one that produces the desired effects.
