Have you heard about the popular new diet trend called intermittent fasting? It’s been popping up in health blogs, Instagram stories, and Twitter feeds, but intermittent fasting is not a new concept or a passing fad.
In fact, intermittent fasting is not really a diet—it’s a pattern of eating.
It goes way back thousands of years to our hunter-gatherer ancestors, who would go long periods of time without food until they hunted for their next meal. Back then, food was scarce, and they didn’t have to worry about eating too much.
Fasting has roots in religion as well—in Judaism, Islam, Christianity, and Hinduism, to name a few.
Today, when food—and not just any food, but refined, processed, and genetically modified food—is within reach, we’ve created a culture of overabundance, overeating, and many health issues that accompany those things.
Intermittent fasting is a way to gain control over your food intake in a world where food is easily accessible.
You’re probably wondering how a diet like this affects your body. Won’t it slow down your metabolism? Will it zap you of energy? What about blood sugar spikes when you eat after a long fast? Can you actually lose weight on a diet like this? We’ll answer all of these questions and more.
You’re also probably wondering how does one go about intermittent fasting. We’ll get to that too.
What Happens to Your Body with Intermittent Fasting
If you think intermittent fasting sounds “unhealthy”—well, you couldn’t be more wrong.
Research shows a large number of health benefits associated with intermittent fasting, including improved insulin response, weight loss, cardioprotection, neuroprotection, and longevity.
In times of overabundance, sugary treats, and refined carbohydrates, many people are walking around with insulin resistance—or chronically high blood sugar.
When the body is loaded with a high number of calories or sugars, the cells become desensitized to insulin. In response, insulin levels increase, even more, signaling the muscle, fat, and liver cells to absorb glucose.
The result of constantly high glucose levels is increased fat storage, increased oxidative stress, and increased inflammation in the body.
When you fast, your insulin levels are at their lowest. Once the body gets used to having low insulin levels, it no longer needs to be resistant to insulin. Instead, insulin sensitivity increases—which means that the body’s cells become more receptive to small amounts of insulin.
Lower insulin levels mean less fat is being stored and more fat is being burned. Insulin sensitivity enables the body to use energy more efficiently.
Research shows that intermittent fasting improves insulin response, lowers blood sugar, and decreases the risk for chronic diseases like type 2 diabetes, coronary heart disease (CHD), obesity, and peripheral vascular disease (PVD). (1)(2)
When the body is in a fed state, it is digesting; absorbing nutrients, fats, and sugars; and responding with increased insulin levels.
About 8–12 hours after finishing a meal, the body enters a fasting state. During this time, the body burns fat more quickly because insulin levels are low.
Once the body is tapped out of glucose to burn for energy, it switches over to use stored fat. This is the key to weight loss with intermittent fasting.
Don’t worry about messing with your metabolism. Once your body gets used to intermittent fasting—because it knows that it will eventually get fed and not starve—your metabolism adjusts. Instead of holding on to fat, it readily burns fat during the fasting state. (1)(3)(4)
Intermittent fasting helps to lower many risk factors for cardiovascular disease, including obesity, high blood pressure, high cholesterol levels, high blood sugar, and inflammation. (5)(6)
A 2005 study published in the Annals of Nutrition and Metabolism measured physiological and psychological changes in Muslims during Ramadan—a month in which Muslims fast daily from sunrise to sunset. What they found was an increase in “good” HDL cholesterol levels during Ramadan. (7)
The nervous system becomes fragile and more susceptible to degeneration with age. This is evident in the large number of older people with neurodegenerative disorders such as dementia, Alzheimer’s, and Parkinson’s diseases.
Experts see neuroprotective properties with calorie-restricted diets and intermittent fasting. These patterns of eating reduce inflammation, provide more energy, and affect stress response systems in ways that protect neurons from genetic and environmental aging factors. (8)
Research is in favor of intermittent fasting for preventing neurodegenerative disorders such as Alzheimer’s disease. (9)
Energy and Longevity
Many people report having more energy when they practice intermittent fasting. Balanced blood sugar levels, lower inflammation, and better overall health are to thank for this benefit.
Believe it or not, intermittent fasting can slow down aging and prolong your life. (10)(11)
It has to do with the effect that intermittent fasting has on certain genes. Studies find that fasting downregulates certain genes related to aging and degeneration of the body.
Intermittent Fasting Strategies
Rather than jumping straight into the deep end, experts recommend first getting your toes wet and gradually getting in. You need to give your body time to adjust to the new feeding schedule, or the whole thing will come crashing down.
Start small and work your way up for best results.
1. Time-Restricted Feeding
Probably the most popular strategy, time-restricted feeding (TRF) involves eating only during a restricted window of eating time each day. As you progress, you can narrow that window down.
Start with the 12:12, which is 12 hours between dinner and breakfast the next morning. If you start eating at 8:00 a.m., make sure to stop eating by 8:00 p.m.
Next, extend the fasting time to 14 hours so that you are eating within a 10-hour time frame. Put off eating until 9:00 a.m. and stop eating by 7:00 p.m.
Some people follow the 16:8 rule—16 hours of fasting with an 8-hour window in which to eat.
2. Cycle Fast
Once you work up to it, you can follow a more extreme fasting schedule every other day of the week.
For example, on Sundays, Tuesdays, Thursdays, and Saturdays, eat on a 12:12 schedule. On Mondays, Wednesdays, and Fridays, eat on a 16:8 schedule.
3. The 5:2 Diet
Once you’ve gotten used to the idea of intermittent fasting, you can up your game by trying the 5:2 diet, which involves eating normally five days per week and fasting—or restricting calorie intake to 500 calories—for two days.
4. Alternate-Day Fasting
This method involves fasting every other day. This is a full 24-hour fast 3–4 times a week, but water, tea, coffee, and any other non-caloric beverages are allowed.
Often, people who follow this method will consume up to 500 calories on the fasting days.
5. The Warrior Diet
Only for true fasting masters, the Warrior Diet comprises a 19- to 21-hour fasting period each day. In other words, you fit all your food into a 3- to 5- hour window.
On this diet, you fast for a full 24 hours—water and other non-caloric beverages allowed—once or twice per week.
Keep in mind that you’ll only benefit from an intermittent fasting eating pattern as long as you keep up with your fitness routine and focus on healthy eating. Make sure not to fall into a trap of bingeing on unhealthy foods during your eating window.
You can gain energy and lower your risk of chronic disease by establishing for yourself an intermittent fasting regimen.
You don’t even have to adopt an extreme fasting schedule to reap the benefits of this type of diet. A simple 12:12 or 14:10 intermittent fasting schedule is still much healthier than the average person’s habit of eating throughout a 16- to 18-hour period each day.
Make sure that fitness and healthy eating don’t fall by the wayside when you start fasting.
If you’re looking for more energy, less fat, lower inflammation, and better health in general, you may want to give intermittent fasting a spin.