Have you ever offered people food and kindly been rejected by them because they’re doing “Intermittent Fasting?”

Fasting? Sounds almost intimidating. However, in this diet you don’t have to specify the foods you eat or starve yourself, you just have to choose an eating window. In other words, you will be limiting your eating to a certain number of hours every day.

Intermittent fasting (IF) focuses on when you eat, rather than on what to eat.

Cutting off the hours you eat during the day can help you reduce your calorie intake as well.

Today more and more people are committing to intermittent fasting for weight loss, boosting metabolism, and preventing lifestyle-induced disease. According to journal article in Nutrition Reviews, “Effects of intermittent fasting on body composition and clinical health markers in humans,” intermittent fasting can help people lose fat and improve metabolic health. The journal suggests that overweight adults who cut calories by 20% every other day dropped 8% of their body weight within 8 weeks. These adults also reported having less inflammation.

So, yes, intermittent fasting can actually work.

However, some experts also disagree on the benefits of intermittent fasting. In fact, one animal study found that an intermittent fasting regimen interfered with the fertility of rats. While, another research article in Journal of the International Society of Sports Nutrition, suggests that intermittent fasting can also impair athletic performance by preventing muscle growth and glycogen replenishment. It is important to learn about and track your body composition —your lean and fat mass— for your optimal appearance and performance and prevent these kinds of muscle degenerations.

There are several different ways of doing intermittent fasting, all of which involve splitting the day or week into eating and fasting windows. The only rule is that you have to keep your fasting period longer than a normal overnight fast of 8-12 hours. Depending on when you work or exercise, if you have family meals or birthday dinners, you can adapt intermittent fasting to your schedule pretty easily. On the other hand, if you have concerns about slowing down your metabolism with intermittent fasting, you can always test your resting metabolic rate (RMR) and make sure to try out different eating windows.

Here are some ways you can play around with it, it shouldn’t get very tricky to navigate:

1. The 16/8 Method: Fast for 16 hours each day. For example if you decide to have an eight hour eating window, let’s say from 1 PM to 9 PM, then, you do not consume any calories in the remaining 16 hours. In a study in the Journal of Translational Medicine, fit people who consumed all their calories in an eight-hour window, fasting for the other 16, lost more fat while maintaining muscle over eight weeks compared to guys who ate normally.

2. Eat-Stop-Eat or The Fast Diet: In this method, you fast for 24 hours, once or twice a week. For example you don’t eat from dinner one day until dinner the next day. So you can eat your normal three meals per day, and then occasionally pick a day to skip breakfast and lunch the next day.

   If you can’t fast for 24 hours you could limit yourself to an 18 hour fast to 22 hour fast. You can always adjust with different eating windows and see how your body responds.

3. The 5:2 diet: Here, five days of the week are normal eating days, while the other two restrict calories to 500–600 per day.

   However, you should keep in mind that eating "normally" does not mean you can eat anything. You still should not consume any junk food or empty calories —foods containing no calories, such as packaged treats like cakes, cookies; energy drinks; alcohol; meats like sausage, bacon; fast foods like pizza, french fries, burgers, and milkshakes etc.

4. Alternate Day Fasting: For the first 24 hours, you only consume water plus 500 calories, either in one meal or spread out over the day. For the second 24 hours, you can eat whatever and whenever you want. Repeat the cycle every two days. A study published in JAMA Internal Medicine, found that people who didn’t track their food but tried alternate-day fasting for one year lost 6% of their bodyweight.

Lauren Harris-Pincus, MS, RDN, author of The Protein-Packed Breakfast Club, suggests that while “there are no specifications or restrictions about what type or how much food to eat during intermittent fasting, anyone attempting to lose weight should focus on nutrient-dense foods, like fruits, veggies, whole grains, nuts, beans, seeds, as well as dairy and lean proteins.”

If done correctly intermittent fasting can:

1. Help You Lose Weight and Belly Fat

   Generally speaking, intermittent fasting will make you consume fewer meals so you can easily end up having fewer calories. According to The Journal of Clinical Investigation research article, when you fast, your insulin levels will stay lower and your growth hormone production will increase, both encouraging your body to burn more calories. If your diet is shaped by more fat and less carbs, you will also be burning fat for energy and decrease your fat percentage.

2. Improve Your Heart Health

   Weight, diabetes, high blood pressure, high cholesterol and lipid levels and high blood sugar are deeply connected to your heart health. Intermittent fasting may improve all of these levels and thus may remove the risks of heart disease.

3. Reduce Insulin Resistance, Lowering Your Risk of Type 2 Diabetes

   Lower blood pressure and protection against type 2 diabetes are connected to insulin resistance. According to Elsevier research article, “Intermittent fasting vs daily calorie restriction for type 2 diabetes prevention: a review of human findings,” IF is promising for weight loss and type 2 diabetes risk reduction in overweight and obese population and has been shown to have major benefits for insulin resistance and lead to an impressive reduction in blood sugar levels.  

4. Reduce Oxidative Stress and Inflammation in The Body

   According to the research article “Beneficial effects of intermittent fasting and caloric restriction on the cardiovascular and cerebrovascular systems” by Elsevier, intermittent fasting can reduce oxidative damage and inflammation in the body. This should also have benefits against aging and development of numerous diseases.

5. Induce Various Cellular Repair Processes

   In a study conducted by the journal Autophagy, fasting caused to increase cellular repair process while removing waste material from cells.

6. Have Benefits for Brain Function

   Several studies in rats suggest that intermittent fasting results in improved brain function such as better learning and memory, and increased production of brain-derived neurotrophic factor (BDNF), which increases the resistance of neurons in the brain to dysfunction and degeneration (1) (2) (3).

7. Help Prevent Alzheimer's Disease

   According to another study in rats by Elsevier, intermittent fasting may delay the onset of Alzheimer's disease or reduce its severity. However, more research in humans is needed.

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