Intermittent fasting isn’t a diet, but rather a dieting pattern. One fasts and then feasts, purposely, meaning eating calories only during a specific window of the day, and not eating food during the rest.
There isn’t one specific way to do it either, you might choose to only eat during a specific time period, such as from 9 a.m. to 5 p.m., or you could choose an even shorter window, such as a 4- or 6-hour part of the day to eat. Another option is to skip two meals one day, taking a full 24 hours off from eating, such as eating at your normal schedule, finishing up at 6 p.m., and then not eating again until 6 p.m. the next day. Then there’s the 5:2 fasting protocol, which calls for restricting calories to just 500 to 700 per day for two days each week.
How intermittent fasting works:
Intermittent fasting is said to be effective because it allows the body to enter its fat-burning peak, which occurs about 8 to 12 hours after a meal. That helps you lose body fat without sacrificing any muscle mass. When one follows a typical eating schedule of breakfast, lunch and dinner spread throughout a 12 hour period, it doesn’t allow the body to reach that point.
Essentially, when you consume a meal, your body will spend a few hours burning what it can from the food you ate. As it has all of this readily available, easy to burn energy in the bloodstream, your body will choose to use that as energy rather than the fat you have stored. That’s particularly true if you just ate a high-carb, sugary meal, as your body prefers to burn sugar as energy before any other source. During a fasting period, your body doesn’t have a recently consumed meal to use as energy, so it’s more likely to pull from the fat stored in your body, rather than the glucose in your blood stream or glycogen in your muscles/liver. All of that results in burning more fat.
Here’s a look at the many reasons to try intermittent fasting from weight loss and well beyond.
1. Weight Loss
The primary reason most people try intermittent fasting is to lose weight. As you’ll be eating fewer meals, unless you compensate by eating a lot more during other meals, you’ll end up taking in few calories, which is the basic formula for weight loss. But as mentioned, intermittent fasting further helps as it allows the body to reach its fat-burning peak, so that you lose fat without losing muscle, the key to successful, long-term weight loss, as it keeps your metabolism running like it should. More muscle means a higher metabolism, and burning more calories.
Research has shown that the 5:2 fasting protocol, restricting calories to just 500 to 700 per day for two days each week, has been the most effective for weight loss. A 2013 British study found that participants who steadily reduced their daily calorie intake became more insulin sensitive and lost more weight, as compared to those who followed a more typical eating pattern.
Research has shown that fasting can raise human growth hormone (HGH) by as much as 1,300 percent in women, and 2,000 percent in men, which is known to play a key role in health, fitness, and slowing the aging process. It also happens to be a fat-burning hormone, which further explains why fasting is so effective for weight loss.
Intermittent fasting enhances hormone function to facilitate weight loss as well as to lower insulin levels, higher growth hormone levels and greater amounts of norepinephrine – all increase the breakdown of body fat and facilitate its use for energy. This is why fasting over a short-term period has been shown to increase the metabolic rate by 3.6-14%, which helps one burn even more calories. In a scientific review conducted in 2014, researchers found intermittent fasting can result in weight loss of 3 to 8% over a 3 to 24-week period, which is a significant amount.
2. Extending Longevity
There are many reasons beyond weight loss to try intermittent fasting, and one of the most exciting may be its ability to lengthen one’s lifespan. It’s been shown to boost the body’s stress resistance, which increases longevity.
Multiple studies conducted on rats found that these effects are similar to the benefits of continuous calorie restriction. In some of the research, experts saw dramatic results, for example, animals that fasted every other day lived 83% longer than rats who didn’t. While more research needs to be conducted on humans, given the scientifically proven benefits for metabolism and a host of health markers, including protecting and treating the body from disease, it makes sense that intermittent fasting can increase lifespan while allowing one to live a healthier life.
3. Lowering Your Risk of Type 2 Diabetes
The rates of type 2 diabetes have skyrocketed in recent years – as of 2012, 9.3% of the American population had diabetes, and over 25% of the senior population have it. There are millions more that are said to be undiagnosed, and it’s the seventh leading cause of death in the U.S.
The disease is mainly characterized by high blood sugar levels in the context of insulin resistance. A major risk factor for type 2 diabetes is being overweight, which is just one of the reasons intermittent fasting offers major benefits in reducing the risk of developing the condition. It also provides major benefits for insulin resistance, which leads to a significant reduction in blood sugar levels.
In human studies focused on intermittent fasting, fasting blood sugar was shown to be decreased by 3 to 6%, while fasting insulin was lowered by 20 to 31%. The dramatic improvement rates of diabetes, 83%, in patients who underwent gastric bypass are believed to be not due to the surgery itself but to the significant restriction in calories that results. Experts think intermittent fasting may mimic this result. Additionally, research on rats that were diabetic, has shown that intermittent fasting helped to protect against damage to the kidneys, which is one of the most serious complications of diabetes.
The bottom line is that intermittent fasting may be especially important for those who are at risk of developing type 2 diabetes.
4. Supporting Heart Health
While much of the research related to heart health and intermittent fasting has been conducted on animals, studies are revealing a lot of promise for this eating pattern to lower the risk of heart disease and related conditions.
Intermittent fasting has been found to increase levels of adiponectin, which has anti plaque-forming and insulin-sensitizing properties, while leptin, a pro plaque-forming adipokine, is reduced. It also improves multiple risk factors, like blood sugar levels, inflammatory markers, total and LDL cholesterol as well as triglycerides, heart rate, and blood pressure, all of which supports better heart health.
5. Slowing Cognitive Decline & Preventing Brain Diseases
Intermittent fasting is said to help protect neurons from both genetic and environmental stress factors that can lead to faster brain aging, cognitive decline, and brain disease. It helps to increase insulin sensitivity, which benefits neurons that stimulate the production of enzymes that help cells cope with stress and fight against disease.
Alzheimer’s disease, the world’s most common neurodegenerative disease, has no cure, which means at this point, prevention is the only cure. Research has shown that intermittent fasting may delay the onset of Alzheimer’s, or lessen its severity. Lifestyle intervention that included daily, short-term fasts found that Alzheimer’s symptoms were dramatically improved in 90% of patients. Other studies have suggested that intermittent fasting may protect against other neurodegenerative diseases too, like Huntington’s and Parkinson’s disease.
6. Reducing the Risk of Cancer
Intermittent fasting has been found to provide a number of beneficial effects on the metabolism that may lead to a lower risk of cancer.
In a 2014 study out of Jefferson Medical College at Thomas Jefferson University in Philadelphia involving 7,000 women with a history of anorexia nervosa, the participants were found to have a 50% reduction in the instance of breast cancer, which suggested that severely restricting calories may help protect against the disease.
Calorie restriction has also been linked to a significant anti-inflammatory response in humans, which may inhibit cancer progression and malignant conversion. In cancer patients, restricting calories combined with radiation therapy aided tumor regression and delayed metastasis. Research on mice in which they followed a calorie-restricted diet was found to have a 55% reduction in the incidence of breast cancer.
Intermittent Fasting Options:
As mentioned, there are a number of different ways to do intermittent fasting. Keep in mind that whichever strategy you choose, it’s something that you can maintain indefinitely, especially when it comes to losing and maintaining weight. If you don’t, you’re just about guaranteed to regain any weight that you lose, once you change your eating habits after achieving your weight loss goal. You should be able to continue some form of intermittent fasting, though it may be fewer days per week, or fasting on individual days for a shorter duration indefinitely after your goals have been achieved.
The 5:2 diet, as mentioned, has been shown in scientific studies to be the most effective for weight loss. It involves eating normally 5 days a week, and restricting calories to 500 to 700 calories two days of the week – generally the lower number for women and a higher number for men. It’s also referred to as the “Fast diet.”
This method involves restricting your daily eating to a window of 8 hours each day and fasting for the other 16 hours. You can eat for the 8 hours that work best for you, for example, between 7 a.m. and 3 p.m. You might eat smaller meals between these times, or eat a slightly larger breakfast and lunch and skip dinner altogether. You can drink coffee, herbal tea, water and other non-caloric beverages while you fast, which also helps to reduce hunger levels. There are many different options, so you can use it in a way that best suits you. This diet is also known as the “Leangains protocol.”
Alternate day fasting.
This method is another common way to follow intermittent fasting. It’s just what it sounds like: you eat one day and fast the next. The downside is that it’s harder to follow than the others, as on the day you fast, you’ll be going to bed with an empty stomach. Some people don’t have a problem with it, but if you do, and find yourself constantly cheating, it won’t be effective, which means you’re better off choosing a different method.
Fasting for 24 hours, 2 days a week.
This method of fasting involves 24-hour fasts twice each week. You basically fast from dinner one day, to dinner the next, for example, on Sunday, you finish dinner at 6 p.m., and then you fast until the following day at 6 p.m. It can also be done from breakfast-to-breakfast, or lunch-to-lunch, the idea is to use the schedule that works best for you, so that you can follow it. You might also start out gradually, with 14 to 16 hours of fasting, and work towards a 24 hour fast.
The Warrior Diet.
The Warrior Diet was started by Ori Hofmekler, and requires fasting for about 20 hours each day, with one large meal allowed in the evening. It’s based on the premise that feeding the body nutrients it needs in sync with circadian rhythms, and that humans are inherently nocturnal eaters, “programmed for night eating,” according to Hofmekler. During the fast, a few servings of raw fruit or veggies are allowed, as is a small amount of protein and fresh juice. In the four-hour period in which you can eat, Hofmekler recommends eating veggies, protein, and healthy fats, but if you’re still hungry, you can add healthy carb-rich foods like whole grains. While this method is easier than total fasting, it’s still difficult to follow long-term, so it may not be the best option for most people.