Intermittent fasting is becoming increasingly popular in health and wellness circles, due to the cognitive and physiological benefits it can produce. Individuals claim intermittent fasting helps them lose weight, sleep more soundly, and concentrate better.
What are the benefits of intermittent fasting? What physical and mental results have been reported? And is there any scientific backing to the growing number of claims?
Below you’ll learn about intermittent fasting benefits and results for mental and physical health across a wide number of studies.
What Is Intermittent Fasting?
Intermittent fasting is the practice of restricting your eating window to a certain amount of time (i.e. 8 hours), then not eating for the remaining hours of the day. The length of the fast varies from person to person, lasting from 16 to 48 hours at a time. The frequency varies as well, with some people choosing to fast on the same day each week (common for a 24-hour fast) or daily (typical for a 16-hour fast).
Proponents of intermittent fasting say it’s a natural biological process. Every person practices a moderate fast on a daily basis, from the moment they go to bed to the time they eat breakfast — intermittent fasting simply extends the time period.
The idea behind fasting is this: Humans were meant to hunt and gather their food, going long periods of time without eating. Only in very recent history could humans simply walk to the grocery store whenever hunger hit. This goes against the conventional wisdom of eating three square meals a day, or even six small meals, popular in weightlifting and bodybuilding circles (1). Read on to find out more about intermittent fasting benefits and results.
Intermittent Fasting Benefits
Intermittent Fasting Can Help You Lose Weight
The most well-known benefit of intermittent fasting is weight loss. In one study done by the NIH, 84 percent of participants who tried intermittent fasting lost weight — no matter the approach (2). Individuals experimented with alternate-day fasting, 16-hour fasts, and other methods, and still lost weight.
Intermittent fasting has been shown to be as effective for weight loss as continuous calorie restriction (3). Some studies show intermittent fasting is more effective at preserving lean muscle mass (compared to calorie restriction) when losing weight. This results in a greater loss in body fat and improved body composition (4).
Finally, intermittent fasting appears to be an excellent tool for losing belly fat. In one study, intermittent fasting for just six weeks showed an increase in metabolism, resulting in a loss of belly fat (5).
Intermittent Fasting Could Help You Preserve Muscle Mass
Compared with other weight loss strategies, a fasting diet helps to prevent muscle loss (8). Other diets which aim to preserve muscle while burning fat, like high-protein diets, show similar success in lowering the individual’s overall BMI. However, intermittent fasting was shown to be more effective at keeping weight off for the long term (9).
Intermittent Fasting Provides Mental Health Benefits
Proponents of intermittent fasting believe humans went thousands of years where food was not readily available. Therefore, they adapted to mentally functioning at a high level, all while in a food-deprived state (10).
Research by Mark Mattson of Johns Hopkins shows intermittent fasting can improve brain health, preventing Alzheimer’s, improving memory, and boosting your mood (11). Lab tests showed that two-day fasts improved neural connections in the hippocampus while protecting neurons against amyloid plaques, believed to be a cause of Alzheimer’s (12).
When you fast, you reduce the glycogen stores in your body, forcing your body to burn ketones (fat stores) for fuel. This has been shown to benefit brain function — it improves memory and learning function, and slows down diseases of the brain (13).
Intermittent Fasting Results
Intermittent Fasting Can Decrease Your Risk of Cardiovascular Disease and Diabetes
Over 29 million Americans have diabetes — 25 percent of which aren’t aware they have the disease (14). Heart disease is the biggest killer in the United States, causing one in every four deaths. Like high blood pressure and high LDL cholesterol, diabetes puts people at a greater risk of developing heart disease (15).
Intermittent fasting has been shown to prevent Type 2 diabetes, thereby decreasing an individual’s cardiovascular risk. It reduces inflammation, improves fasting glucose levels, decreases insulin resistance, decreases oxidative stress, and reduces blood pressure — all indicators of heart disease (16). One study showed that intermittent fasting was as effective at improving fasting insulin and insulin sensitivity as restricting calorie intake (16).
Intermittent Fasting Can Help You Live Longer
Weight loss, improved insulin levels, and decreased blood sugar levels (just a few health benefits of intermittent fasting) will increase your lifespan. Studies show that intermittent fasting will prolong your life more than other practices that offer these same benefits. For example, animal studies show that intermittent fasting prolonged lifespan more than exercise (17). Another study done on rats showed alternate-day fasts increased the lifespan by 83 percent compared the consuming same amount of calories each day (18).
In human studies, intermittent fasting has been shown to extend longevity by improving your stress resistance and reducing obesity, hypertension, asthma, and rheumatoid arthritis. Therefore, fasting can help slow the aging process (19).
Intermittent Fasting Can Help Prevent Cancer
In 2018 alone, roughly 1.7 million people in the United States will be diagnosed with cancer (20). In animal studies, alternate-day fasts increased the survival rate of rats with tumors (21). Other studies showed that intermittent fasting greatly reduced the onset of lymphoma (cancer of the lymph nodes) (22).
Fasting might also help improve the negative side effects of chemotherapy (22). Patients who underwent chemotherapy while practicing intermittent fasting noticed reduced fatigue, weakness, and gastrointestinal side effects (23).
Recap: Health Benefits and Proven Results of Intermittent Fasting
While intermittent fasting is known for being an effective weight loss tool, science has shown a wide range of other health benefits. These amazing results range from mental to physical, helping individuals:
- Lose weight
- Improve their BMI and maintain muscle mass
- Decrease their risk of heart disease, diabetes, and cancer
- Live longer
Some of the available research backing these claims have only been done on animals, but the number of human studies continues to grow. Given the number of studies, intermittent fasting is a great tool for living a long, healthy life.