What Happens During Intermittent Fasting? How It Really Works

The big hype nowadays is intermittent fasting to lose weight, but does it really work and is it worth starving yourself for the desired results? Intermittent fasting is a kind of diet that doesn’t focus on what you eat rather than when you eat.

How does it work?

So many people are trying intermittent fasting to lose weight and luckily Intermittent fasting is very flexible, and you can decide during what hours or days you will be fasting. Weight-loss is only one of many benefits of intermittent fasting. People having difficult work schedules may not be able to even eat during their eating window and will struggle to get a routine going. It is important to get your schedule for intermittent fasting right to be able to stick with it. Luckily there are a few methods of intermittent fasting and the chances are good that one will fit your lifestyle.

During the fasting period no eating is allowed and also no sugary drinks. No carbs at all. Black tea or coffee without sugar is very popular during fasting periods and also drink enough water.

Water has many functions in the body and is needed for healthy functioning body cells. Water functions as a way for the body to get rid of toxins, regulate body temperature through sweating, transporting oxygen and nutrients throughout the body just to name a few.

4 Different intermittent fasting methods to lose weight

1) 16:8 method

The 16:8 method is the most common fasting method and works well if you want to lose weight. Fasted workouts also works well with this method. You have a 16-hour fasting period during each day and an 8-hour eating window. This method is the easiest to stick with and to become a routine and eventually a way of living. The easiest way to make this method work is by fasting while you sleep. Eat dinner no later than 20h00, skip breakfast and eat a healthy lunch at 12h00. In between you can drink black coffee or tea without sugar which will help with the hunger pains.

If you struggle at first to hold out till 12h00 for lunch or you have work that requires a lot of labor where fatigue influences your work, then try the 12-hour (fasting only 12 hours) method first. Works the same as the 16:8 method but you have a longer eating window. Once you get used to the 12:12 method you can try to make the feeding period shorter to 14:10 and then later on 16:8.

2) 5:2 method

This method might also be relatively easy to follow. Eating normally 5 days a week and then restricting your calories to between 500-600 for two days. This method isn’t true fasting, but the goal is to limit your carbs drastically two days a week. During fasting days, for men it is 600 calories and woman 500 calories and is about 25% of the normal calorie intake needed for adults. The amount of calories a body needs per day differs with age and gender and also body type and can range from 2000-3000 calories.

It is also important to get the schedule for intermittent fasting right and not to do the 2 fasting days back-to-back and to give your body time and nutrients to prepare for the next fasting day. It is also easier to stick with this fasting method when you spread out your fasting days. The amount of calories you have on fasting days aren’t really enough for 3 meals and is probably best just skipping a meal. Some people will eat breakfast and get super hungry a few hours later, in this case it would be better to hold off from eating as long as you can or skipping breakfast all together.

3) Alternate day fasting method

This method involves fasting one day and eating normally the next day and then the pattern repeats itself. This is a more extreme fasting method and require full 24-hour days of not eating any calories. Most people find it easier to stick with this method when they eat dinner and then wait until the next day’s dinner time to eat again.

If you like this fasting method but struggle too much on fasting days, you can always just limit your calories. On fasting days, you can limit your calorie intake at first to between 500-600 until you get used to the routine. Then after a while you can try the no calories on fasting days approach.

4) Eat-stop-eat-method

Another extreme fasting method is the eat-stop-eat fasting method and is a lot like the 5:2 method. Here you will be fasting a full 24-hours once or twice a week. If you are doing it twice a week don’t do it consecutively but spread it out throughout the week to make it more bearable.

Common mistakes while following a fasting method

Most people try intermittent fasting to lose weight and general well-being. Many people try a fasting method for a week or even two and don’t see the desired results, so they abandon the fasting method because there’s a lack of motivation to continue. Remember your body first needs to adjust to the new eating routine before the fasting will start to work. When it starts working you will constantly be losing weight. The amount of weight loss will depend on the amount of calories you eat during your eating window.

The big mistake people make is during the eating window where they will overeat and eat large amounts of calories. Hunger does that to people and for your particular fasting method to work you need to eat normally during your eating window. Carbo loading during eating window will slower or even halt progress.

Most of the fasting methods basically force you to miss a meal and create a smaller eating window giving you less chance to snack. Snacks are the number one enemy for any weight loss program.

The 3 stages of fasting

1) Fed state

This state lasts a few hours after eating a meal depending on what you ate and how much you ate. This is where your body digests and absorbs nutrients and can last between 2 and 4 hours. Your insulin level will spike while glucose and other nutrients are absorbed during digestion. These nutrients will be transported, converted and stored in the liver and skeletal muscle cells for later use. Carbs (glucose) get stored in the form of glycogen.

2) Early fasting state

This stage begins when your insulin levels begin to drop caused by your stomach emptying and food digesting coming to an end. Lower insulin levels have the opposite effect than rising insulin levels. During the early fasting state lower insulin levels will encourage the breakdown of stored glycogen in the liver and muscle cells. This stage begins at around 4 hours after a meal and can last up to 18 hours. At the end of the early fasting state glycogen reserves will get depleted and the body starts searching for a new energy source. The 16:8 intermittent fasting method will cycle between the fed state and early fasting state.

3) Fasting state

The fasting state begins at around 18 hours after your last meal. After 18 hours of fasting your glycogen reserves in liver and muscle cells are depleted and your body will start to break down muscle protein and fat reserves as a new energy source.

Your body changes its metabolic state where the primary energy source is fat and is called ketosis. Many factors (size and composition of last meal, sex, age, genetics etc.) will affect the beginning of ketosis and it may take a while for your body to transition fully into ketosis.

Following a ketogenic diet will cause your body to transition faster into ketosis for more fat burning and weight loss. Following a fasting method where you fast for 24-hours straight will benefit from ketosis.

Can I exercise while fasting?

You can stimulate even more weight loss by being active and exercising regularly.

Doing cardio/ endurance exercise near the end of your fasting period can help you burn more fat. Stored glycogen will be mostly depleted depending on your fasting method, and your body will start to burn more fat for energy to cope with the exercises. The downside to exercising on an empty stomach is fatigue and lightheadedness. You won’t be able to push you as hard as when you were still in the fed state.

When you are doing weight/ resistance training, your goal is to gain muscle mass. Fasting isn’t the best way to achieve that, with fasting your goal is to lose weight. Prolonged fasting (24 hours or more) will in fact trigger your body to utilize muscle protein for energy as well as fat reserves to generate energy (glucose). That is not to say that you can’t or shouldn’t follow a fasting method while doing resistance training. You just need to make sure that you eat enough protein for muscle growth and also the exercise should still be intense enough to trigger muscle growth. You also need a surplus of carbs to meet the energy requirements during training. If there is a deficit in protein or carbs, muscle mass will start to decline because there are not enough building blocks for muscle growth.

What happens to your body after a meal? After a meal your blood glucose will spike and also your insulin level. Insulin is the main hormone that regulates the metabolism of carbohydrates, fat and protein and is secreted by the pancreas. Insulin promotes the absorption of glucose from the bloodstream into the liver and skeletal muscle where it is converted into glycogen or fat. Thus, a low level of insulin will have the opposite effect by breaking down fat stores and glycogen for energy. Your body will always try to keep your blood sugar in the ‘normal range’ to functioning optimally.

Conclusion

So, which fasting method works the best? The short answer is the one you are able to stick with long term. Some of these fasting methods described above are easier to stick with than others and some of the more extreme ones are not really sustainable for long periods of time.

Following a fasting method may cause you to experience some side effects like fatigue, light headedness, decrease of concentration, headaches, nausea etc. In this case I suggest starting with the easier fasting methods like 12:12. Once your body is used to the new feeding schedule you can decrease the eating period.

Extreme hunger can also cause you to overeat during your eating window and can cause you to eat more unhealthy foods instead of becoming healthier. The trick here is to try to eat normally, it may be very difficult in the beginning, but you do get used to going without food for longer periods of time.

Prolonged fasting (24 hours or more) will have a detrimental effect on muscle mass and muscle growth. During long fasting periods muscle proteins will be broken down together with fat to meet your body’s energy requirements.

Our bodies are evolutionary designed for fasting periods, when we were still hunter/gatherers there would be many times where food is scarce and natural fasting will be the result. Our bodies aren’t used to or adapted to eating snacks all day and that is why modern-day society battles with obesity so much. Of course humans in the past were also much more active and burned more calories on a daily basis.