Intermittent fasting: your ultimate guide

If you were to go onto social media right now, and ask the question “How can I lose weight?”, a large number of people will enthusiastically recommend intermittent fasting.

The popularity of this diet can’t be denied, but how does it work and is it safe and healthy? In this comprehensive guide we’ll delve into the fundamentals of intermittent fasting.

First things first. What is intermittent fasting? 

Fasting is nothing new. People are forced to fast when there is no food available, and fasting also forms part of certain religions. The human body is well equipped to handle short periods of fasting.

Intermittent fasting differs from other diets in that it doesn’t dictate what you eat, but rather when you eat.

The basis of intermittent fasting is that by restricting food, our bodies will tap fat stores of energy more quickly and  efficiently.

Glucose from carbohydrates is our most direct fuel source, and when glucose isn’t available we burn fat for energy. This happens even more during periods of food deprivation.

The fasting periods in intermittent fasting can range from several hours to days, with the most common approaches involving daily fasting windows followed by feeding periods. 

During the fasting phase, no caloric intake is allowed, although water, tea, and black coffee are typically permitted. 

In contrast, the feeding window lets you consume your usual meals and meet your caloric needs within a designated time frame.

Some forms of intermittent fasting allow small amounts of low calorie foods during the fasting period.

Taking supplements is generally allowed while fasting, as long as there are no calories in them.

Many people report feeling better and more energetic during a fast, but this is not the case for everyone, as some people do report not feeling great and not having much energy.

It is possible that you will get hungry, which is more likely if you follow a pattern of fasting for an entire day multiple times a week.

Intermittent fasting methods

This eating pattern can be approached in many different ways. These are a few of the most popular methods:

• Alternate day fasting. This entails fasting every other day by restricting your calorie intake to only 30% of your usual calorie consumption.

• Eat-stop-eat is a 24-hour fast, free from calories, done once or twice a week.

• The 16/8 method involves fasting for 16 hours, and then eating within an eight-hour time frame. This means that a large part of your fasting time can be at night when you sleep.

• With the 5:2 approach you will fast for two days out of every seven, and only consume 500-600 calories on fasting days.

• Partial fasting means that you will eliminate certain foods of drinks from your regular diet for a set amount of time. This could, for example, be animal products, processed foods, sugar or caffeine.

• One Meal A Day (OMAD) is a fasting method where you eat one large, nutritious meal per day. During the rest of the time you are only allowed drinks that contain no calories.

How does fasting affect your body?

When you fast, interesting things happen in your body on cellular and molecular level. Some of these changes are: 

• Your levels of human growth hormone can increase as much as fivefold. This has benefits for fat loss and muscle gain.

• Insulin sensitivity improves and insulin levels drop dramatically. This helps to make stored body fat more accessible.

• Your cells initiate cellular repair processes. They digest and remove old and dysfunctional proteins that build up inside cells.

• Gene expression occurs – changes in the function of genes related to longevity and protection against disease.

These changes in hormone levels, cell function and gene expression are behind the health benefits of intermittent fasting.

Benefits of intermittent fasting

Unlike some fad diets out there, intermittent fasting comes with a slew of health benefits. Here’s why it’s good for you:

• It’s an effective means to lose weight. Studies showed that it’s probably not more efficient than the traditional method of calorie restriction, but it might be easier to maintain long term.

• Intermittent fasting can help prevent diabetes. Research shows that it can reduce insulin resistance, which plays a huge role in type 2 diabetes.

• Being overweight is one of the main risk factors for developing type 2 diabetes. This means that weight loss through intermittent fasting can be a preventative measure.

• A review from 2016 reported that this eating pattern could improve cardiovascular health.
  Intermittent fasting can lead to a decrease in blood pressure, heart rate, cholesterol and triglycerides. Triglycerides are a type of fat in the blood that is linked to heart disease.

• By controlling inflammation, blood sugar levels and insulin resistance, intermittent fasting also supports brain function. Studies also showed that intermittent fasting may increase the growth of new nerve cells, which benefits the brain.
  Animal studies showed a reduced risk to develop neurological disorders like Alzheimer’s, Parkinson’s or a stroke.

• Another series of animal studies indicated that restrictive diets such as intermittent fasting could protect you from cancer.

• Oxidative stress occurs when free radicals react with other important molecules such as proteins and DNA, and damage them.
  According to a review in 2018 intermittent fasting may help the body resist oxidative stress.

• A 2023 study found that intermittent fasting can help to activate autophagy – a cellular waste removal process.
  During autophagy, cells break down and metabolise dysfunctional proteins that can build up over time. This protects the body against various conditions, such as cancer and Alzheimer’s.

• All of the above implies that intermittent fasting can help you to live longer.

10 points to consider before you start

While the benefits are undeniable, it’s good to start your journey with an open mind, knowing what to expect so that hurdles along the way don’t throw off your progress. Keep these points in mind:

1. If you are on medication, or you are just unsure, talk to your doctor. You can never be too careful with your health.

2. If you’re a diabetic and take insulin, be very careful. Intermittent fasting puts you at a greater risk of low blood sugar, which can be extremely dangerous.

3. Find a fasting plan that works for your individual needs in the long term – don’t be afraid to switch between plans to find the best one.

4. Be prepared for some side effects, especially in the beginning. You should feel better in time. If these symptoms are so bad that you struggle to tolerate them, rather stop your fast.

5. Get professional advice if you experience feelings of depression and anxiety. Fasting might not be for you.

6. The fact that you are fasting does not mean that you can go overboard with unhealthy food during your eating periods.
   Whole, unprocessed foods including whole grains, fruit, veggies, lean protein, healthy fats with plenty of water are always the best way to go.
7. Since we get some of our water from food, fasting can leave you dehydrated, so don’t forget about water.

8. Understand that intermittent fasting is a long term plan. It might take months before you start seeing results.

9. It’s wise to have a friend or family member who can support you.

10. Intermittent fasting becomes even more beneficial when combined with daily exercise.

Potential problems with intermittent fasting

A few nasty side effects may discourage you right from the beginning.

It’s hardly a surprise, but hunger is one of the most common side effects of intermittent fasting. Going for longer periods without food will take some getting used to.

You may also experience headaches and lightheadedness. Reducing the amount of food you eat can lead to changes in digestion. You may experience indigestion, diarrhoea, nausea, and bloating.

Healthy food choices containing sufficient fibre can help you combat these symptoms.

Low blood sugar when practising intermittent fasting can also have an effect on your mood. Look out for irritability, anxiety, poor concentration, fatigue and lack of energy.

Another pleasant side effect includes bad breath. Fasting causes your body to use fat for fuel. Acetone is a byproduct of this process, and causes bad breath along with dehydration.

When you just start fasting, the body releases a lot of water and salt through urine. If you don’t replace the fluids and electrolytes you lost, you can become dehydrated.

Lastly, ensure that your diet is balanced and nutritious. Malnutrition becomes a risk on a badly managed diet.

Intermittent fasting is not for everyone

Despite all the potential health benefits, fasting poses a risk to people who already have certain conditions. 

Fasting is not the only way to achieve a healthy lifestyle or weight loss. If you fall into one of these groups, best avoid fasting and investigate other methods, or chat to your healthcare practitioner: 

• You are older than 65.
• Children and teens who are still growing and developing.
• Patients with diabetes or heart, kidney or liver disease.
• You have a history of eating disorders.
• You are pregnant or breastfeeding.
• You have low blood pressure.
• You take medications such as blood thinners, diuretics, blood pressure medication or medication that affects your blood sugar.

Conclusion

Despite thousands on social media raving about all the weight they lost with intermittent fasting, it’s important to remember that it’s not some miracle cure for obesity.

Eating windows are not for catching up for when you couldn’t eat and you still can’t eat anything and everything you might be tempted to. Stick to healthy meals – it’s all about balance.