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Intermittent fasting or IF, as it is commonly known, has become a buzzword in the world of health and fitness. But there are so many people who are still sceptical to give it a shot. Put those worries to rest, because multiple randomized trials reveal how helpful this method is to reduce weight, and rev up your metabolism and cardiovascular health.
A review titled Intermittent Fasting and Obesity-Related Health Outcomes published in the journal JAMA found that intermittent fasting has associations with weight loss and improvements in metabolic and cardiovascular health. Plus, it was noted that some kinds of intermittent fasting are more helpful when it comes to weight loss.
Before we dive into those details, let us first understand what intermittent fasting really involves. To help us out, we have Parul Malhotra Bahl, Nutritionist, Certified Diabetes Educator, and Founder at Diet Expression, who shares more with HealthShots.
Most of us are already aware that fasting has been a practice that has been followed across various cultures to lead a healthy lifestyle. But what’s important to understand is the difference between fasting and starvation. Bahl explains, “Fasting is very different from starvation. Starvation is the involuntary (uncontrolled) absence of food, whereas fasting is the voluntary (controlled) abstinence from food.”
This is exactly the principle around which intermittent fasting revolves. It is all about abstaining from food entirely or partially for a set period of time before you start eating regularly again, she says.
The food we eat is broken down in our gut and eventually ends up in the form of molecules in our bloodstream. Carbohydrates, particularly the simple carbs (sugar, white flours, rice, etc) are quickly broken down into sugar, which our cells use for energy. If our cells don’t use it all, we store it in our fat cells as fat.
“Sugar can only enter our cells with the help of a hormone called insulin. Insulin brings the sugar into the fat cells and stores it there. Between meals, as long as we don’t snack, our insulin levels can go down and our fat cells can then release their stored sugar, to be used as energy. So, the longer we don’t eat, the more stored sugar in the form of fat will be released and used,” explains Bahl.
Fasting is the most effective and consistent strategy to decrease insulin levels. Since the body switches over to burning stored fat for energy during the fasting state, it helps in weight (fat) loss.
Many studies have explained how simple fasting improves metabolism, lowers blood sugar levels, says Bahl. Intermittent fasting lessens inflammation, which improves a range of health issues from arthritic pain to asthma, and even helps clear out toxins and damaged cells, which lowers the risk for cancer and enhances brain function.
Bahl shares details about various methods of doing intermittent fasting.
This is the 16:8 fasting method, in which you fast for 16 hours and eat in the remaining eight hours of the day. During fasting, one is allowed to have only water or any zero-calorie drink. It is important to know when and what to eat during the eating window. Two to three meals (2 main with a small snack in between) that are high on fibre, protein, and good fat work the best.
This is the most comfortable form of intermittent fasting (especially for first timers), and can be easily sustained for a longer period of time.
Alternate day fasting is where people end up avoiding any solid food or restricting to 500 calories a day every alternate day.
“Alternate day fasting is quite an extreme form of intermittent fasting, and it may not be suitable for people who have never fasted or those with certain medical conditions. It may also be difficult to maintain this type of fasting in the long term,” shares Bahl.
Also known as the Eat-Stop-Eat diet, this intermitent fasting pattern involves eating no food for 24 hours at a time. Many people fast from breakfast to breakfast or lunch to lunch.
“People on this diet plan can have water and other calorie-free drinks during the fasting period. On non-fasting days, one can eat in a regular pattern. Eating in this manner reduces a person’s total calorie intake, but does not limit the specific foods that the individual consumes,” explains Bahl.
A 24-hour fast can be quite challenging as it may lead to fatigue, headaches, or irritability. Over a period of time, people may get used to this new eating pattern, and start seeing the benefits.
This is a relatively extreme form of intermittent fasting.
The warrior diet involves eating very little; just a few servings of raw fruit and vegetables, during a 20-hour fasting window, and then eating one large meal at night. The eating window is usually only around 4 hours.
“Although it is possible to eat some foods during the fasting period, it can be challenging to stick to the strict guidelines on when and what to eat in the long term. Also, some people struggle with eating such a large meal so close to bedtime. There is also a risk that people on this diet will not eat enough nutrients, such as fibre,” shares Bahl.
This is the 5:2 diet in which out of seven days in a week, people eat normal, healthy food for five days and reduce calorie intake on the other two days. During the two fasting days, men consume around 600 calories and women consume 500 calories. Typically, there should be a minimum gap of 1 day between two fasting days.
As per the JAMA review, both modified-alternate fasting and 5:2 diet may be an effective means of lowering heart disease risk by decreasing blood pressure, low-density lipoprotein (LDL) cholesterol, and triglycerides. Moreover, these diets may help prevent type 2 diabetes by lowering insulin resistance and fasting insulin.
Plus, the modified alternate fasting diet and 5:2 diet produced a weight loss of more than 5 percent in people who were overweight or obese.
While intermittent fasting may be helpful, Bahl says it isn’t safe for pregnant women, children, people who are at a risk of getting hypoglycemia, or have a history of eating disorders and chronic diseases.
Also a much-needed word of caution, ladies! “Always check with your doctor or nutritionist before you decide to start Intermittent Fasting,” concludes Bahl.