Is Fasting an Effective Way to Lose Weight?
Fasting is a time period in which you voluntarily restrict yourself from eating. Fasting can be undertaken for religious or health reasons, and has been practiced for thousands of years. It is an integral part of our daily lives because we are intermittently fasting anytime we are not eating. For instance, the time between your last meal before going to bed and the first meal of the next day, which is approximately 12-14 hours, is when you fast. This is why the first meal of the day is called breakfast, as you are breaking your overnight fast.
Fasting for weight loss
Fasting has recently gained considerable popularity for weight loss and falls under the umbrella of fad diets. As a weight loss strategy, it focuses less on what you eat than when you eat. This is why for some people, fasting feels more manageable than cutting and counting calories daily.
Generally, fasting involves restricting energy intake for a few days per week or few hours each day, resulting in an overall weekly calorie deficit without restricting food groups. This calorie deficit allows your body to use its stored energy by burning off the excess fat without posing a risk of nutritional deficiencies.
For example, studies have shown that overweight and obese individuals can lose 3%-8% of their basal weight and reduce their waist circumference by 4%-7% by fasting intermittently for three to 12 weeks. Fasting may also lead to much smaller muscle mass reduction during weight loss compared to continuous calorie restriction approaches, which may result in better exercise performance. However, there is no research related to the effectiveness of fasting in achieving and maintaining weight-loss goals in the long term.
Popular fasting regimens
Many fasting regimens, such as fasting windows in a day to whole day tests, are currently trending. Some of these include:
1. Alternate day fasting
This regime involves alternate days of unrestricted eating followed by one day of complete abstinence from food and drink.
2. Alternate day modified fasting
This fasting method recommends alternating days of unrestricted eating followed by partial fast days, which usually include 25%-50% of basal energy requirements.
3. Intermittent fasting
This fasting regime endorses one to two fast days per week and eating freely on the remaining days. For instance, the 5:2 diet comes under this category.
4. Time-restricted fasting
This is the most popular fasting approach that suggests eating all your meals within a controlled timeframe every day. Some examples of this type are 16:8, wherein you fast for 16 hours and eat for eight hours, and 20:4, wherein you are fasting for 20 hours and eating only for four hours each day.
However, fasting does not give you the license to eat large portions of unhealthy, high-calorie, and high-fat foods during non-fasting periods. You still need to eat recommended portions of each food group to maintain a negative energy balance and avoid health complications.
How does fasting affect your body?
Calorie restriction through fasting can potentially bring about several changes in your body’s metabolism.
- It creates an acute negative energy balance within your body during which the body exhausts its glucose stores and switches over to a fat-burning state.
- It decreases your blood glucose levels, thereby preventing extra energy from being stored as fat.
- It may dramatically reduce your blood insulin levels by 20%-31% and improve your cells’ insulin sensitivity, which enhances the use of your stored fat to generate energy.
- It may stimulate your nervous system to send chemical signals to your fat cells, instructing them to break down fat into fatty acids that can be used for energy production.
- It may lower your heart rate and blood pressure by boosting your basal metabolic rate, which is the amount of energy your body burns while resting by 4%–14%
- It may reduce oxidative stress within your body by decreasing the production of inflammatory chemicals and harmful free radicals.
- It may raise the breakdown of old or damaged white blood cells while simultaneously triggering the production of new white blood cells, thus improving your body’s immunity.
- It may decrease the levels of triglycerides and LDL cholesterol in your blood by improving liver function and health.
Health benefits of fasting
Apart from weight loss, here are a few plus points of fasting:
1. Improved cognitive performance
Studies indicate that intermittent fasting may boost working memory and verbal memory.
2. Reduced risk of cardiac diseases
Research suggests that intermittent fasting may decrease blood pressure regulation and resting heart rate and improve lipid profile and other heart-related parameters.
3. Reduced risk of metabolic diseases
Fasting may reduce the risk of diabetes and obesity by lowering blood glucose levels and enhancing insulin sensitivity.
4. Slows down aging
A few studies indicate that fasting may delay the body’s aging process by reducing oxidative damage of cells and improving cellular regeneration.
5. Supports cancer treatment
Limited research suggests that fasting may lessen the harmful side-effects of chemotherapy, particularly suppressing the immune system.
6. Reduced risk of inflammatory diseases
Fasting may reduce the symptoms of irritable bowel syndrome and arthritis.
Does fasting have any side-effects?
Unplanned and unsupervised fasting may cause adverse effects like:
- Increased hunger
- Hyperacidity and heartburn
- Fatigue and dizziness
- Lack of concentration
- Weakened immune system, liver and kidney problems, and irregular heartbeat
- Vitamin and mineral deficiencies
Is fasting the right approach for you?
Fasting is a safe weight loss approach for healthy, well-nourished people. However, it may not be ideal for certain individuals such as:
- Women who are pregnant or breastfeeding
- People with diabetes
- People with nutritional deficiencies
- People with a history of eating disorders
Although the finer details of fasting regimes may be equally susceptible to trends, fasting is one of the longer-standing fad diets for which relatively more scientific evidence exists. It may also provide other health-related advantages compared to the more conventional chronic energy restriction approaches to weight loss.
However, do note that all fasting regimes may have varying effects on different people. Therefore, it is best to consult a dietitian or nutritionist before adopting this method for weight management. They can help you understand your nutritional needs and customize a safe fasting program that suits your lifestyle and weight loss goals.
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