Intermittent fasting is an eating pattern that focuses on restricting when you eat instead of what you eat and is made up of fasting and eating windows. The fasting windows either consist of water only or a calorie-controlled diet.
How Intermittent Fasting Works
Intermittent fasting works by reducing your calorie intake during regular intervals. The science behind weight loss caused by intermittent fasting is simple: by prolonging the time between eating periods, your body burns through calories and starts burning fat.
The three standard intermittent fasting methods differ in the length of time of the fasting and eating windows. The 16/8 method, 5/2 method, and alternate-day method are the most popular to follow and split the day or week into eating and fasting periods.
The Diet Plan
There are several different ways to pursue the intermittent fasting diet. The one you choose should fit your lifestyle and habits.
A 16-hour fasting window is followed by eight hours of eating with no calorie restrictions.
Two non-consecutive fasting days or low-calorie days where the total calorie intake is fewer than 500-600 calories per day and eat normally for the remaining five days of the week.
Fast one day (24 hours) or have a low-calorie day, then eat normally the following day.
Exercise is not part of the intermittent fasting plan; however, the more physically active you are, the more calories you burn.
Unlike many fad diets, there are no fees for plans, programs, or special meals.
Intermittent fasting is widely publicized, with many example diet plans and meal ideas available, and dieters claim it is one of the most affordable diets available. When you think about it, during the fasting window, you reduce the number of meals you eat daily, consequently cutting your grocery bill.
Dos and Don’ts
Read through this checklist of dos and don’ts before starting your intermittent fasting journey.
- Check with your doctor to ensure you are fit and healthy to fast.
- Start slowly to allow your body to adapt to the changes.
- Choose fasting and eating windows that suit your lifestyle and stick to them.
- Listen to your body. If you feel faint, headachy, or overly fatigued, stop fasting.
- Drink water — remaining hydrated while fasting is crucial s a lot of water in our diet comes from food.
- Binge eat before or after a fasting window.
- Engage in vigorous physical activity while fasting and stick to light to moderate exercise.
- If you are pregnant, breastfeeding, underweight, under 18 years of age, or have a medical condition, it is advised not to attempt intermittent fasting.
Sample Diet Plan
The great thing about intermittent fasting is its flexibility. You can pick your fasting and eating windows to suit your eating preference and schedule.
16/8 Meal Plan
To follow the 16/8 diet, choose eight hours of the day you would like to eat and fast for the rest. People on this plan commonly skip breakfast, break their fasting at lunch, and eat from 12 to 8 p.m. This allows you to make the most of fasting overnight and enjoy lunch, dinner, and snacks. Try 9 a.m.-5 p.m., allowing for breakfast, lunch, and early dinner!
Sample 16 hours/8 hours eating windows:
12 p.m.-8 p.m.
2 p.m.-10 p.m.
8 a.m.-3 p.m.
9 a.m.-5 p.m.
5/2 Meal Plan
Again, there are no set rules on what to eat and when, but a calorie limit exists of 500 calories for women and under 600 for men on fasting days. The best way to stay fuller for longer is to focus on eating nutrient-dense, high protein foods such as vegetables, fruit, natural yogurt, boiled eggs, and lean meats. A final tip is to fast during weekdays; people that follow the 5/2 diet plan find it a lot easier.
Sample 5/2 fasting windows:
- Fast Monday and Wednesday
- Fast Tuesday and Thursday
Alternative Day Meal Plan
The alternative day fast is either water only, or the more sustainable modified version is to eat 25% of your total energy requirements; for women, this is around 500 calories, and for men, 600. Opt for nutrient-dense foods to feel fuller for longer on a restricted calorie intake.
Fasting Day Meal Plan
- Fresh fruit
- Natural yogurt
- Boiled eggs
- Lean meats
Health Benefits and Drawbacks
Intermittent fasting has been proven time and time again to be a beneficial tool for weight loss and, more importantly, weight loss maintenance. A 12-month study examined adherence, dietary intake, weight loss, and metabolic outcomes in overweight adults who choose to follow Mediterranean, Paleo, or intermittent fasting diets. Participants who chose intermittent fasting had more significant long-term weight loss than other diets.
Intermittent fasting is growing in popularity due to its variety of health benefits for the body. It may reduce the risk of heart disease by controlling the risk factors, including weight, blood pressure, cholesterol, and blood sugar levels. More importantly, it aids in inhibiting the development of atherosclerotic plaque (build of fat on the heart’s walls) by reducing the number of inflammatory markers.
Intermittent fasting has been used to help treat patients with diabetes. Studies proved a reduction in insulin requirements through improved glucose metabolism, insulin, and insulin sensitivity.
New evidence has highlighted that intermittent fasting can even increase lifespan and brain function. However, this research has only been proven in animal studies.
Like any diet, the health benefits are not without drawbacks. The diet stands out by focusing on when you eat; therefore, no attention is paid to the diet’s quality. Dieters can be intermittent fasting and still eat “unhealthy” processed and refined foods.
Intermittent fasting has been linked to adverse effects on female fertility by increasing the risk of irregular menstrual cycles and lowering the chance of conception in animal and human studies. For ovulation to occur, a woman needs sufficient energy and body fat. Restrictive eating impairs this, and it has been reported that some women’s periods stop when they start intermittent fasting and return when they finish.
Going for prolonged periods without eating can cause a few side effects. Dieters have reported headaches, inability to focus, and a tired body due to low blood sugar levels. A five-year study found that fasting increases the chances of binge eating and the onset of eating disorders.
Take these disadvantages into consideration before starting fasting.
The Bottom Line: Is Intermittent Fasting a Healthy Way to Lose Weight?
Intermittent fasting is a popular, safe, and effective way to lose weight, and it is easy to understand why. For its additional health benefits, flexibility, and simplicity! If you are trying to lose weight, experiment with intermittent fasting and find a method that works; chances are you will stick with it!
Meagan Morris is the editor in chief of Celebribody. She's veteran health and wellness editor with over 15 years of experience. Her work has been featured in The Atlantic, Yahoo Health, Cosmopolitan, SELF, and Women's Health, among others. She spends most of her time writing, but her favorite part of the day is spent under a barbell doing squats.