Practical tips for fasting

We’ve dealt extensively with the science of fasting earlier, but sometimes there are many practical considerations that need exploring, too. Fasting, like anything else in life requires some practice.

In days past, when religious fasting was a communal practice, these sort of practical tips were passed on from generation to generation. If not, friends would often have useful advice on how to handle the fasting, because there are definitely some problems that commonly arise.

However, with the decline in the practice of fasting, these sorts of advice are often difficult to find. Unless you’re reading this.

What can I take on fasting days?

There are many different rules for fasting. During Ramadan, for example, fasting is practiced from sunrise to sundown and no food or beverages are taken. Other types of fasting will only restrict certain types of foods – for example, abstaining from meat for a day. So there are no right or wrong rules.

What I describe is the fasting that we prescribe for health and weight loss, as we use in our Intensive Dietary Management program.


All calorie-containing foods and beverages are withheld during fasting. Be sure to stay well hydrated throughout your fast. Water, both still and sparkling, is always a good choice.

Aim to drink around two liters of water daily. As a good practice, start every day with eight ounces of cool water to ensure adequate hydration as the day begins. Add a squeeze of lemon or lime to flavor the water, if you wish. Alternatively, you can add some slices of orange or cucumber to a pitcher of water for an infusion of flavor, and then enjoy the water throughout the day.

You can dilute apple-cider vinegar in water and then drink it, which may help with your blood sugars. However, artificial flavors or sweeteners are prohibited. Kool-Aid, Crystal Light, or Tang should not be added to the water.


All types of tea are excellent, including green, black, oolong and herbal. Teas can often be blended together for variety, and can be enjoyed hot or cold.

You can use spices such as cinnamon or nutmeg to add flavor to your tea. Adding a small amount of cream or milk is also acceptable (even if it’s technically a tiny cheat). Sugar, artificial sweeteners or flavors are not allowed.

Green tea could be an especially good choice, as the catechins in it are believed to help suppress appetite.


Coffee, caffeinated or decaffeinated, is also permitted. A small amount of cream or milk is acceptable, although these do contain some calories. Spices such as cinnamon may be added, but not sweeteners, sugar or artificial flavors. On hot days, iced coffee is a great choice. Coffee likely has many health benefits.

Bone broth

Homemade bone broth, made from beef, pork, chicken or fish bones, is a good choice for fasting days. Vegetable broth is a suitable alternative, although bone broth contains more nutrients. Adding a good pinch of sea salt to the broth will help you stay hydrated.

The other fluids — coffee, tea, and water — do not contain sodium, so during longer fasting periods, it is possible to become salt-depleted. Although many fear the added sodium, there is far greater danger in becoming salt depleted during fasting. For shorter fasts such as the 24- and 36-hour variety, extra sodium may not be required, but during longer fasts it can be important.

All vegetables, herbs or spices are great additions to broth, but ideally do not add bouillon cubes, which are full of artificial flavors and monosodium glutamate. Beware of canned broths: they are poor imitations of the homemade kinds.

Here’s a recipe for bone broth.

Break your fast gently

Be careful to break your fast gently. There is a natural tendency to eat large amounts of food as soon as the fast is over. Interestingly, most people don’t actually describe overwhelming hunger, but more of a psychological need to eat.

Overeating right after fasting may lead to stomach discomfort. While not serious, it can be quite uncomfortable. This problem tends to be self-correcting, i.e. most people will avoid it next time.

Try breaking your fast with a handful of nuts or a small salad to start. Then wait for 15-30 minutes. This will usually give time for any waves of hunger to pass, and allow you to gradually adjust. Short duration fasts (24 hours or less) generally require no special breaking of the fast, but certainly for longer fasts it is a good idea to plan ahead.

I get hungry when I fast. What can I do?

This is probably the number one concern. People assume they’ll be overwhelmed with hunger and unable to control themselves. The truth is that hunger does not persist, but instead comes in waves. If you’re experiencing hunger, it will pass.

Staying busy during a fast day is often helpful. Fasting during a busy day at work keeps your mind off eating.

As the body becomes accustomed to fasting, it starts to burn its stores of fat, and your hunger will be suppressed. Many people note that as they fast, appetite does not increase but rather starts to decrease. During longer fasts, many people notice that their hunger completely disappears by the second or third day.

There are also natural products that can help suppress hunger. Here are my top five natural appetite suppressants:

  1. Water: As mentioned before, start your day with a full glass of cold water. Staying hydrated helps prevent hunger. (Drinking a glass of water prior to a meal may also reduce hunger.) Sparkling mineral water may help for noisy stomachs and cramping.
  2. Green tea: Full of anti-oxidants and polyphenols, green tea is a great aid for dieters. The powerful anti-oxidants may help stimulate metabolism and weight loss.
  3. Cinnamon: Cinnamon has been shown to slow gastric emptying and may help suppress hunger. It may also help lower blood sugars and therefore useful in weight loss. Cinnamon may be added to all teas and coffees for a delicious change.
  4. Coffee: While many assume that caffeine suppresses hunger, studies show that this effect could be related to antioxidants. Both decaffeinated and regular coffee shows greater hunger suppression than caffeine in water. Given its likely health benefits, there is no reason to limit coffee intake. The caffeine in coffee may also raise your metabolism further, boosting fat burning.
  5. Chia Seeds: Chia seeds are high in soluble fiber and omega 3 fatty acids. These seeds absorb water and form a gel when soaked in liquid for thirty minutes, which may aid in appetite suppression. They can be eaten dry or made into a gel or pudding.


Can I exercise while fasting?

Absolutely. There is no reason to stop your exercise routine. All types of exercise, including resistance (weights) and cardio, are encouraged. There is a common misperception that eating is necessary to supply “energy” to the working body. That’s not true. The liver supplies energy via gluconeogenesis. During longer fasting periods, the muscles are also able to use fatty acids directly for energy.

As your adrenalin levels will be higher, fasting is an ideal time to exercise. The rise in growth hormone that comes with fasting may also promote muscle growth. These advantages have led many, especially those within the bodybuilding community, to take a greater interest in deliberately exercising in the fasted state. Diabetics on medication, however, must take special precautions because they may experience low blood sugars during exercise and fasting.


Do you want to know much more about intermittent fasting? Check out our full guide:

Intermittent fasting for beginners

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Earlier with Dr. Jason Fung

The Common Currency in Our Bodies Is Not Calories – Guess What It Is?

Why the First Law of Thermodynamics Is Utterly Irrelevant

How to Fix Your Broken Metabolism by Doing the Exact Opposite

More with Dr. Fung

Dr. Fung has his own blog at He is also active on Twitter.

His book The Obesity Code is available on Amazon.

The Obesity Code

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