Fasting For Weight Loss: A Quick Guide

With so many fad diets pushed by television and social media daily, it can be hard to find one that’s safe and healthy. If dieting doesn’t work for you, try fasting for weight loss. It might be what can finally give you the results you’ve been looking for.

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Does fasting really help you lose weight?

When you fast, you don’t eat for hours at a time, sometimes an entire day. You often only have a certain window to eat your meals. This ensures that you’re only getting the calories you actually need.

Depending on how much idle eating you already do, the pounds may drop off quite quickly. Eating only within a certain time frame helps you stop mindlessly snacking throughout the day. Best of all, you likely won’t be forced to cut out your favorite, less healthy foods (within reason!) when it’s time to eat.

How it works

Fasting changes the way that your body burns and stores fat. Insulin is responsible for fat storage and converting glucose (sugar) from your food into usable energy. When you fast, your insulin levels decrease and you won’t hold on to as much excess fat.

Your cells will also become more insulin sensitive, increasing their ability to use the carbohydrates that you eat for energy, keeping your blood sugar in a stable range. This causes your body to use less energy during the fast, naturally lowering your blood pressure and heart rate.

As your body enters ketosis, it will start burning only the fat cells in your body. This is the main cause of your weight loss while fasting, plus it balances your blood sugar levels as well.

Unlike many crash diets, intermittent fasting is backed up by scientific evidence. A Harvard overview of 40 studies revealed that fasting can potentially cause a weight loss of 11 pounds in ten weeks. The fasting individuals didn’t experience any increase in appetite, according to a quarter of these trials.¹

What are some examples of fasting methods?

There are several intermittent fasting schedules you can follow, but here are the most popular ones:

  • 16:8 fasting

  • 5:2 fasting

  • Alternate-day fasting

  • Eat-Stop-Eat

  • The Warrior Diet

Let’s take a look at each one of them.

The 16:8 fasting method

This type of intermittent fasting is often the easiest one for beginners since you only have to fast for 16 hours a day. That might seem like a lot, but remember that the average person already fasts for up to 12 hours daily. After your last meal, you usually wind down before you go to sleep for at least eight hours.

When you wake up, you might linger in bed or take a shower before you actually get hungry. For many people, switching to a 16:8 eating schedule is as simple as skipping breakfast. You’ll have eight hours to eat whatever you need for the day.

The 5:2 fasting method

For those who don’t want to fast every day, the 5:2 method might work better. On this plan, you can eat five days a week without limiting your calories. For the remaining two days, you can only eat a quarter of your recommended calories.

Depending on your body type and activity level, that’s only around 500 to 600 calories per day. Eating so little in one day can make you cranky; some might even feel lightheaded and faint. To be on the safe side, make sure there’s a normal eating day between the two fasting days.

Alternate-day fasting (ADF)

For alternate-day fasting, you eat a quarter of your calories (or none at all) every other day. On non-fasting days, you’re usually allowed to eat whatever you feel like eating.

Because this method is relatively extreme, it might be impossible for people with certain medical conditions.

Eat-stop-eat method

For the eat-stop-eat regimen, you fast for 24 hours at a time and eat normally the next day. During the fast, you’re only allowed to drink calorie-free drinks like water, black coffee (without sugar), or tea. Because this method involves such a long period of fasting, it is one of the most effective ways of switching your body into fat-burning mode.

This method is only recommended for one or two days of the week, but it can still be challenging for beginners. Additionally, going for so long without food increases your chances of binge eating once your fast is up.

The Warrior Diet

With the Warrior Diet, you’re only allowed to eat tiny portions of your daily calories over the course of 20 hours. This might include big servings of raw fruits and veggies, hard-boiled eggs, or low-fat dairy products. For the remaining four hours of the day, you can eat whatever you want.

The Warrior Diet is relatively unpopular because you have to eat certain foods. It also takes an incredible amount of willpower to fast for so long. Additionally, there aren’t any studies yet that prove this method is better than other forms of intermittent fasting.

Does fasting have other health benefits?

In addition to losing weight, fasting helps your body:

  • Decrease insulin resistance

  • Fight inflammation

  • Increase growth hormones (which promote muscle strength, weight loss, and healthy blood sugar levels)²

  • Lower cholesterol

  • Boost metabolism

  • Improve heart function³

Additionally, several animal studies have shown the promising benefits of fasting. Long-term fasting, for example, seems to benefit the brain structure of mice, improving their thinking processes and memory.⁴

Another study also showed that intermittent fasting increased the lifespan of rats by 83%.⁵

Does fasting have any side effects or complications?

When you first begin intermittent fasting, you may experience:

  • Headaches

  • Irritability

  • Difficulty falling asleep

  • Constipation

  • Low blood sugar

  • Weakness or fatigue

It can take as long as four weeks to adjust to a fast.⁶ However, if you fast for too many days at a time, you may experience long-term health problems like anemia, vitamin deficiencies, depression, and disordered eating patterns.

High-risk groups may experience these problems with something as simple as the 16:8 method.⁷ Consult your doctor before attempting any kind of fast if you are:

  • Elderly

  • Immunocompromised

  • A minor

  • Pregnant

  • Diagnosed with a chronic disease

  • Diagnosed with an eating disorder

However, even if you are none of the above, it’s still a good idea to discuss any change in diet with your doctor, especially when it comes to intermittent fasting.

How do you succeed at fasting?

If you’re new to fasting, don’t do the Warrior Diet immediately just because you want fast results. Ease yourself into fasting slowly and find the method that works best for your body. When you find something you can handle, you’re more likely to stick with it.

Also, don’t be discouraged if you don’t lose weight right away; everyone’s metabolism is different, especially in the beginning.

Learn how long it can take to start seeing weight loss results.

On your fasting days, it’s also recommended to have as little physical activity as possible. You should keep yourself hydrated and get plenty of sleep.

On your regular eating days, focus on eating whole foods that aren’t too high in fat or sugar. Don’t gorge yourself during your non-fasting days, otherwise, your weight loss attempt will be more challenging.

If you notice yourself binge-eating after or in between a fast, it might be time to try a new fasting method or a different weight loss strategy.

The lowdown on fasting for weight loss

Intermittent fasting has been proven to improve both mental and physical health. However, it can do more harm than good if you fast too much or if you have underlying health conditions.

Before jumping headfirst into fasting for weight loss, consult your doctor. Ease into it slowly and listen to your body to make sure fasting is right for you.

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