Practical Fasting Tips – Part 12

posted in: Fasting, Health and Nutrition | 90

We’ve dealt extensively with the science of fasting, 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.

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 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 Tea

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 of milk is also acceptable. Sugar, artificial sweeteners or flavors are not allowed. Green tea is an especially good choice here. The catechins in green tea 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 has many health benefits, as previously detailed.

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. For shorter fasts such as the twenty-four- and thirty-six-hour variety, it probably makes little difference. All vegetables, herbs or spices are great additions to broth, but 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. (See below for a bone-broth recipe.)bone broth

Broth Recipe


Chicken, pork or beef bones

1 tbsp of vinegar

Sea salt, to taste

Pepper, to taste

Ginger, to taste

  1. Water to cover
  2. Simmer for two to three hours until ready
  3. Strain and de-fat

How do I break my fast?

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.

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:coffee

  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.(1) 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 is likely related to anti-oxidants. Both decaffeinated and regular coffee shows greater hunger suppression than caffeine in water.(2) Given its health benefits (see chapter 21 [REF.]), 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 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. (See “What if I have diabetes?” for recommendations, in next post.)

Start with Fasting part 1

For more tips continue here for Fasting part 13

90 Responses

  1. Is a fasting day a good way to recover from eating something like a piece of cake during a celebration. I am a Type 2 diabetic ,following LCHF and eating potatoes and birthday cake last evening has dramatically increased my blood glucose number-both 2 hr pc and fasting the next morning.

    • I am inclined to say it is…

    • absolutly do not do a fast if you are diabetic. You can easily do more harm than good. Talk to your doctor before venturing into a fast, you will be hard pressed to find a physician who will not worry that you may end up in emerg.

      • huh?

      • Linda – diabetics can fast. The recommendation is to work with the Doctor as medications may need to be lowered.

      • Bad advice! T2D absolutely can fast. Dr. Fung addresses this in this article! Only precaution is if they’re medicated fasting could cause hypoglycemia if not monitored closely. Stay on top of your glucometer readings and consult with doctor. Many T2D control BS with LCHF and fasting and don’t need to be medicated. There is zero risk of hypoglycemia if unmedicated.

      • You are so wrong.. Terrible advice!!
        Fasting, when done through Dr. Fung’s advice, can dramatically reduce insulin, and eventually reverse diabetes. A personal physician and pharmacist are the last people I would seek advice from. For the most part, there advice is what gets diabetics in trouble in the first place!!!

      • This is an uncorroborated post……fasting as a diabetic is a WONDERFUL way to cure the condition…. Just work with a health professional who KNOWS what they are talking about…. The only issue with fasting as a diabetic is if you are on medication which needs to be monitored when fasting….hence, work with a health care professional who is knowledgeable in this area…

      • Read all of Dr. Fungs blogs before you say fasts are wrong for diabetics. Many have reversed diabetis thru a fasting regime. Find a doctor who really understands diabetis. Most don’t, in my experience.
        Bottom line: fasting is a way to reduce blood glucose levels… just get educated on the do’s and don’ts – and get a real doctor.

    • Carmen Smith

      I am a T2 Diabetic and I do full long fasts, between 3 to 10 days at any given time. I wouldn’t give advise if I wasn’t sure of what I am saying. I do not take any metformin and I am under Dr. Fung’s care and my diabetes is almost reversed. LCHF is a wonderful woe. Education is the key.

  2. Dr. Fung, I have of late taken a keen interest in fasting as part of my extensive study on dieting and diet. I have a health evidence based website. I have come up with a simple fast, and would like to get your opinion on it. It is not specifically aimed at type-2 diabetes or obesity. And I recommend that if sufficient progress is not made on the JK short fast, to switch to a full alternate day fast as you recommend.
    JK short fast: go on a 16 hour fast (7 PM until 11:00 AM) or longer, thus extending the beneficial nighttime fat burning production of ATP (the energy molecule) to midday. At night because of not eating there is low glucose and thus insulin is not secreted by the pancreas. The body then metabolizes fat for energy (ATP). If hunger becomes an issue than eat a small handful of nuts, green vegetables, or low-carb power bar to kill pangs; the effect of a small portion on insulin production is minimal.
    For obesity I recommend the JK short fast along with the New Atkins diet.
    Related question there are a number of lower calorie fast including one by Dr. Mosley of the BBC (500 calories on fast days). I have my doubts about their worth for long-term weight loss or health benefits, since most don’t restrict refined carbohydrates. What is your opinion?

    • Deb Griffith

      The 5:2 plan DOES work…I started it in mid April and lost 12 lbs rather quickly, then upgraded to ADF, 16:8 and LCHF/high protein. Down 25 lbs. You can read the success stories at

  3. Thank you Dr.F. I will share this on my fasting group, Fung Shweigh…My group is inspired by your teachings.. . This info plus all the rest and all your webinars comes in very handy for us to follow. I have a few folks following your fasting protocol. Thank you for all you do .. if we didnt have you to follow many would still have have high insulin, blood sugars and weight to lose as our own doctors really do not help with what they have learned. I prefer your way best…

    • Sandy, would you please check your facebook inbox messages? I’ve just messaged you …

  4. Does it really only take people 2 to 4 days to use up all glucose in the body? I heard it can take some people a week to start burning fat. Is that true?

  5. I forgot to say that it can take me about 5 days of very low carb to make my hunger subside, but not completely. Is it not a very good idea to restrict or fast when you obsess over food?

  6. Hello Dr.Fung,

    Thanks for writing this series on Fasting, it’s interesting.

    I have a question about the statement:

    “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 able to use fatty acids directly for energy.”

    Say someone does a 5-day fast. They do resistance training on day 3. What happens according to you, scenario 1, 2 or another one entirely?

    Scenario 1: the hypertrophy stimulus will be ‘wasted’ because the raw materials (protein & calories) don’t follow, but muscle mass is still retained.
    Scenario 2: the hypertrophy stimulus is not ‘wasted’ since it will ‘carry over’ to when the fast is broken, not only resulting in muscle mass retention but the normal degree of hypertrophy as well.


    Dr. Jason Fung: Hey Raphi! I am not an expert on exercise physiology, so you may need to check with Dr. Steve Phinney or Tim Noakes. My own thought is that the stimulus is not wasted, but your body does certainly need some amino acids for cellular repair and muscle building. So, most people exercise at the end of their fasting period so that they will then take a high BCAA meal.

  7. Thanks Dr Fung. Looking forward to what you have to say in your next post ” what if I have diabetes” and my exercise when fasting.

  8. Onlooker

    On bone broth: 2-3 hours is woefully inadequate to extract all the good nutrients out of the bones. It’s just getting started at that point! Better to let them simmer for 24-48 hours (lesser for chicken, more for beef) to really let the bones, cartilage and other tissues fully break down, thus making for a truly superior nutrient profile.

    Just search for “bone broth” and there’s lots of good guidance out there from the Weston A. Price Foundation and others.

    • I agree. I simmer mine for a day or more in slow cooker.

      • The slow cooker works great for this.

        • Agreed. We cook ruminant bones for 72 hours and poultry for 12 hours. A crockpot with a locking lid makes it easy to do this out in the shed or garage without smelling up the house.

    • Don’t make the same mistake I did. If you cook on stove top let your broth simmer so only an occasional bubble gurgles to the top. A rolling boil breaks down the collagen.

  9. What about taking a well formulated Multiple Mineral Vitamin during a 30 to 60 day fast?

  10. Julia Billen

    Dr. Fung – exercising raises my blood sugar – after a run I can get up to 170 (T2D). Should I wait until I have become more insulin sensitive before I exercise rigorously? I’ve taken to walking only lately so that I keep by blood sugars down but have read that exercising will increase insulin sensitivity….Thank you for your posts. Your work is changing my life. – Julia

    Dr. Jason Fung: Increased blood sugar is not a reason to reduce exercise. I would continue.

  11. ron stone

    Been practicing the IF lifestyle since 2012 , will add that if real hungry then sugar free gum or bubble gum has been a lifesaver as well as pickles.

    • stephanie

      How can chia seeds been consumed during the fasting state as they do have calories?

  12. Martina Elena Romero

    Greetings! if you on fasting, do you need to take metformin, my doctor gave me metformin twice a day. Thanks

    Dr. Jason Fung: Only your own doctor can advise you on your medications. However, be aware that metformin can cause GI upset on an empty stomach. Also, if your blood sugars are too low during fasting, you should seek advice on holding metformin or any other you other diabetic meds.

  13. Carol L.

    Thanks so much for this article Dr. Fung!

    A quick question, would a bone broth be inappropriate for someone with gout?

    Dr. Jason Fung: I see no problem.

  14. “All calorie-containing foods and beverages are withheld during fasting. ”

    So this would exclude my bullet proof coffees that are loaded with melted butter and heavy cream? I was also adding coconut oil to my bone broth. Yes, you are very clear in this article, but I am still somewhat in denial… This could be why I have not lost any weight in 2 months of 42-60 hour fasts… I am in your diet program working with Megan, and she recommended I go on a week long fast, which I started today.

    Dr. Jason Fung: Some people do fine with some fat during a fast – coconut oil or bulletproof coffee. Others do not.

    • What I meant to say is that my bullet proof coffees WOULD BE excluded…

    • Cassandra

      Hey Dana! I’m on day 2 of a 7-day fast today. If you check in on the Forum we can support each other. P.S. I don’t lose if I take too much fat during a fast so I’m keeping the hwc to two tbs this time around.

      • [email protected]

        Thanks Cassandra! See you over in the forum…

        • Dana, I am having the same problem you are and am now restricting the bulletproof coffee. It would be nice to compare notes. How does one get onto the forum?

      • Elaine in Big D

        Hi Cassandra, did you continue with 7 day fasts? Any specific tips or cautions to share? Thanks a million!

      • Dr. Fung, what do you mean by “Some people do fine with some fat during a fast – coconut oil or bulletproof coffee. Others do not.”

  15. Diana Choi

    Dr. Fung,

    How long should my husband fast for if he has type 2 diabetes? Please advise. Thanks.

    Best regards

  16. Hi Dr. Fung. Great website with a lot of good information. I’m doing LCHF to lose weight and want to incorporate fasting to obtain the additional health benefits. Based on your clinical experience would you please tell me which fasting protocol provides the most benefits the soonest?

    Thanks in advance.

    • Jennifer

      Hi Cub,

      Dr Fung has mentioned before that the longer the fasting period the better and more intense the benefits will be. However if you struggle with longer fasts (36+ hours at a time) it is of course better to do a few shorter fasts (16-36h) than nothing at all. Shorter fasts can be done more frequently as well (up to 23h a day every day ie eat once a day or every other day) whilst 2-3 day fasting should only be done once a week. It all comes down to you trying out what works best for you in the long run. Good luck!

      • Hi Jennifer, thank you for your kind response. Based on your response I’ve thought about this:Would it be ok to do a 23 h short fast five days a week plus two 24h fasts per week? or is this too much?

        • ccavanaugh66

          What the Dr. Says is that you don’t want to do anything too regularly– it’s good to vary the pattern.

        • Jennifer

          hi cub, unless you start feeling bad/dizzy/low energy or feel cold it is not too much to fast that much (unless you are of course underweight). Just make sure when you eat that you get lots of nutrient-densed foods such as meat, veggies (broocli, cabbage, caluiflower, asparagus, avocado etc), eggs, nuts, seeds, fat (butter, coconut oil, cheese, heavy cream, olive oil etc) as you will want to get as many nutrients as possible in your one meal a day. And dont restrict calories during that meal (only restric sugar, gluten and fast carbs). Good luck!

  17. Mineral water is terrific for many of the issues people have while fasting. I keep some (Gerolsteiner, Pelegrino, Perrier) on hand, and find I rarely get leg cramps unless exercising more strenuously. Broth at night is relaxing, but can stimulate some hunger if I have it earlier. Green tea is gold! I used to over brew it and it got bitter; so timing is key. I like having such a wide variety of green, black, herb teas to add interest to fasting.

  18. Dr fung. Thank you for life saving information. Am I right in deducing that 1 x 48 hour fast has better outcomes (lower insulin, more fat burning) than 2 x 24 hours fasts (that is 1 x 24 hour fast; feast day; 1 x 24 hour fast)?

    • Jennifer

      Hi Cate, I have asked a similar question before and yes, the longer the fasting period the more intense benefits, however some people find it more manageable to do 2x24h as you then get to eat once a day, and maintenance is key for longterm benefits. Also, everyone is different and some people (not me) see great benefits with 16:8, which is a very simple fast. I need to do 24-36h at least to see weight results (the longer the better) however I find that for me personally after 40-46h I start to get irritated and only think about food so I have that as my personal cutoff point.

  19. Hector D

    Can diet beverages such coke zero be consumed during the fasting period?

    • Jennifer

      Hector D, studies have shown that sweeteners also increases insulin so it is not recommended, but if you need one to manage the fast I would guess it is better than not fasting at all, just less effective benefits…

      • Thank you Jennifer!!! you guys are truly heaven sent. I have been fasting now for several months and I feel fantastic. My BP went from 136/94 to 120/72!!!! my body weight was 225 and now I am 198 and feel and look younger.!!!

  20. What about alcohol on fast days? I mean something like vodka. I have just realised a day I’ve set for fasting is a day that I drink. I’d say 6 units, or less. Roughly, but it’s not fixed, just depends.

    • Julia Billen

      I can’t speak for Dr. F but have read in his writings that it is best to stick to zero calories drinks. Alcohol may interfere with your bodies ability to breakdown fat which is ultimately the goal if you have metabolic disease. I do not drink during my fasting periods currently – only my festing days.

      • I do the same: I drink only on my non-fasting days. I think I would get hammered if I had a single drink while fasting. Even when I drink, I drink at most 2 drinks. If I want to have a drink, I will ensure I cease to fast before I drink.

    • Jennifer

      I dont think it is healthy to consume alcohol on an empty stomach. I’m no expert but would guess that when you havent eaten in a long time the first thing that you consume to break the fast will get very quickly absorbed into the body as it is really keen on getting new energy. That way the alcohol may go to the wrong organs such as the brain (maybe) and cause damage. I may be wrong but I would not dare to try…

    • I have experimented with IF and drinking a non-carb drink such as whiskey. Here’s the problem I’ve experienced. Say I eat 1,000 calories and drink 3 oz of whiskey. When alcohol is consumed, all other digestive processes come to a stop until the alcohol is metabolized. It takes from 1-2 hour per oz to metabolize, so 3 oz could take up to 6 hours. 6 hours after you’ve started your fast does your body start to digest the 1000 calorie meal you ate and that takes another 8-12 hours to rid yourself of the glucose from that meal. So as a maximum, you’ve got 18 hours to rid yourself of the glucose. If you’re doing a 16:8 or even a 20:4 IF, your fat burning is almost non-existent.

  21. I too am curious about alcohol.

  22. I am trying to fast every other day, which is one of the suggested ways. I am finding that losing weight is very slow. But I’m not entirely sure if I’m the days that I’m eating I’m actually eating correctly because I’m trying to do this simply by watching the videos, and the videos you have to piece together what you should and shouldn’t eat. So for instance in one place he said you can eat all the fruit you want. But in another place it lists only a few pieces of fruit with skin like apples. So I’m not sure if it’s the fasting protocol that’s hindering my weight loss, or if its on the days that I eat that I’m not restrictive enough even though I’ve cut out all grains, all corn products, all sugars, and all refined foods altogether. I’m eating lots of vegetables, fruit 3 or 4 times a day, being very careful about meat and dairy products having cut back significantly, no snacking, no cheating, etcetera. Any thoughts on why I might not be losing weight? I’m barely eating 13 to 1400 calories a day even though I’m eating till I’m completely full at each meal.

    • Fruits hinder weight loss greatly, especially for me. Try eating more meat, fish, veggies, eggs, good fats like butter, coconut oil instead of the fruits.

    • I know this is a late response but it’s for the benefit of others.
      Eating fruit 3-4 times a day is a great way to keep them insulin levels up all day. Eating 1300-1400 calories a day is a great way to tell your body that you’re on a starvation diet and that it better lower your BMR. I’ve had tremendous success doing 24 hr fasts eating a damn good meals. Same for 48 hr fasts.
      Psychology has a lot to do with success. I’ve been successful (so far) because I simply don’t eat when I don’t eat, but when I do eat I don’t starve myself in the process and make sure I get the good stuff in before I dabble a little with the bad stuff.
      This way…I can continue with this FOREVER.

  23. @drjasonfung Hi ive recently been getting all the symptoms of type 2 diabetes (urinating alot and fatigue etc) i have started fasting im about 30hrs in to my fast no food just water. and all my fatigue has gone and urinating not as much still have a little dryness in my throat. i wanted to know if i should keep fasting for a week etc or not i also am going to change my diet no more bad refined carbs and little amounts of good carbs any advice you could give me would help. because i dont want to go on insulin medication etc i want to try fix or atleast help it many thanks Harry.

  24. Becky, I recommend that you go to for information on how to follow an LCHF- diet on your eating days. There is a lot of useful information there:-)

  25. I have spent the better part of a week now, reading through all blogposts and watching all the videos. It’s been a very interesting week:-), the weather here in Sweden is more reminiscens of October than July.
    I found your page, Dr Fung through Andreas Eenfeldts Swedish blog and I’ve been so inspired. I’ve done a few 20-24 hour fasts these past couple of weeks and now I am aiming for at least 36 hours for the first time.

  26. Dr. Fung, I’m concerned about electrolyte depletion during exercise while fasting. Do I need to replenish my electrolytes, or will the body’s internal stores be sufficient?

    • Michael, I use pickle juice (source of sodium) and magnesium (magnesium taurate, pill form) on the days I fast. If I don’t take these, sometimes I can get leg cramps at night. This includes days I fast and exercise at the same time, although even days I do not exercise, I may have to supplement. However, I’m also taking an ACE inhibitor, which supposedly causes a sodium/potassium imbalance. You can try going without and see what happens. I’ve done a three day fast, taking only a few magnesium pills and a little sodium, and working out twice (aerobics, lifting weights).

  27. Hi Jason. Just a quick question about fasting. I usually do the 16/8 style of fasting but I seem to always get a cold after doing this for a few weeks.
    Is this due to me being deficient in certain nutrients ? Not eating enough during the feeding window?
    I’m 6 1 195lbs so have a higher maintainence requirement.

    Let me know as I would like the besnifits of fasting. Thanks.

  28. DClemons

    Good Morning. I am attempting to tackle my diabetes/pre-diabetes through LCHF and eating in a 6-8 hour window. I’m curious if anyone else has any BS issues like mine (I’m sure there are). I believe that I have Dawn Phenomenon, as when a get up, my BS has been reading in the 120-125 range recently after 10-12 hours of fasting. I am an early riser and usually test between 5 and 6 am. Yesterday I waited until 11:45 am and still got a reading of 121 after a 30 minute cardio hike and jog at 7:30 am. I decided to eat and had 3 eggs with spinach, olive oil, sour cream, a banana and an orange. I don’t normally eat the fruit, but was experimenting. Re-tested my BS after 2 hours and it read 102. This is where my confusion lies, lower BS after eating? This morning I tested at 5:45 am and got 125. Took another 30 minute cardio hike and retested at 8:45 am with the result of 122. At 11 am I ate 1 avocado, 3 eggs with 2 T. butter, spinach, 1/4 c. parmesan cheese, 1/4 cup blueberries and 1/3 cup heavy cream. I will re-test in a few hours, but assume it will be below or around 100.
    History: My doctor has been telling me that I am pre-diabetic for years, slowly creeping up with an A1C of 6.4 in April 2014. He kept telling me to exercise and loose weight and I kept putting off the return visit until I had lost the weight. (never happened) In mid-February 2015 the big toe on my left foot tore open and would not heal. This put me in a state of mild depression. After about a month, I went to my doctor and my left foot had very poor circulation and my toes were cold and bluish. (Winter in VT was my thought) 6′-1″, 219#
    Scheduled a visit with a Podiatrist in mid-April, prescribed 10Mg Norvast for BP and circulation and got me set up with a glucose test kit. My morning numbers were 116-139. I knew I had a problem. Started my research online and immediately found Dr. Fung and started a few 24 hr fasts without really changing my diet. Then stumbled across Tim Noakes and started “Banting” around April 1 and got very excited with the ease of the diet. We vacationed for 2 weeks in April without my meter, kept on the LCHF and returned to BS readings between 102 and 115, weight down to 205. A1C test on April 27 of 6.2, cholesterol test the best in 25 years. Thing were working! Scheduled another A1C and cholesterol for July 22. Laid off the daily testing of BS (twice a week, maybe). Weight down to 195, A1c down to 6.0, cholesterol numbers not as good as April. Morning BS creeping back up!
    My real question is: should I fast for longer periods until my BS gets below 100 or eat to keep my BS down? Any advice would be great! Or, am I OK doing what I’m doing? Trying to get below 180#s and think this is achievable. Just started exercising this week.
    Dave C.

  29. At day five of my first fast. I discovered this website last weekend and thought I would try a fast for a day or two. It has been easy and seems to be working. Keto stix (not the best indicator I know) show dark purple, weight has been dropping, 5 pounds in five days. and BG has hovered around 100 the last few days, down from hovering around 120. Fasting has been easy enough so far that I am going to go a few more days. BP has improved slightly and I am hoping for better drops. I see fasting as really the last resort for me. I hope I won’t have to eat these words but I believe I could go ten days or more of fasting easily. It would be nice to not be medicated although metformin seems to agree with me. If that is the worst of the meds I need to take I would be happy. Its funny that a number of the meds I have had to take on doctors orders have worsened the problems. Diazide raises BG, Metroprolol causes weight gain. I took them both. So far for me the longer fast seem to be easy enough that I will continue with some of the long ones. It is encouraging to see weight loses every day on the scale.

  30. Hello, really great information on the site. I’m finally realizing why I am unable to lose weight even while on a low carb diet! I started with a 76hr fast and have switched to eating one HF/LC/MP meal every 36hrs. I feel so much more energized and my appetite is under control.

    Question about coffee. Doesn’t coffee release insulin? Wouldn’t drinking coffee defeat the purpose of the fasting? So far I’m only drinking iced water through my fast and nothing else.

    Thank You!

  31. Dave C
    It sounds to me that you have had diabetes for a long time.
    You asked for advice re fasting and eating. My advice would be to fast and eat according to Dr. Fung’s advice. Eating low carb and high fat diet. Take your blood sugar readings more not less frequently.
    Dr. Fung has a distance program – see his website at “intensive dietary management.. I am on this program and find it invaluable in answering questions and understanding my own situation. It is very inexpensive at $200 Canadian per year.
    You have been doing very well with losing weight, as this continues your blood sugars should return to norma.

  32. stephanie

    I read in the article that Chia seeds are premitted. I’m curious to why as they do have calories.

    • Chia seeds are virtually all fiber, so they shouldn’t raise insulin levels if you eat 1-2 Tbsp per day.

  33. Walter Bushell

    RE: Salt

    I find that even on low carb, I frequently wake up with bad leg cramps that can be
    cured by eating salt or potassium chloride or a mixture of both.

  34. Abner Williams

    Can commercial bone gelatin be used during fasting instead of home made bone broth?

  35. […] A continuation of practical fasting tips. See Practical Fasting Tips. […]

  36. What about natural stevia ( as a plant ) on fast days.May I use it in my tea ?

  37. Dr Fung, could you please definitively describe how to break a long water fast, 21 days and longer. So much of the information available seems to come from the vegan community, and therefore recommend eating only raw fruit or veg, or juices to break a fast.. There’s a lot of pseudo science about what is happening with your digestive system, and quite a few scare statements too along the lines of you’ll die if you eat meat. I personally want to avoid breaking fast with a spike in insulin from fruit. And staying in ketosis would be good too. What are your thoughts on consuming high quality fats to break fast, eggs, …. And when is it ok to introduce a nice juicy steak?

    • TeeGee, I’m breaking my 7 days (water, salt and green-tea only) fast with bone broth and then a little portion of herring fried shortly (15 sec on each side) in butter – it preserves DHA. Herring is very much overlooked source of highest DHA levels in food that is at the same time the most bio-available. Good nutrition for your cellular membranes after the prolonged fast 😉

  38. I enjoy drinking Kombucha – and it also helps with keeping gut bacteria healthy. A typical bottle has 60 calories and 14 grams of carbs. I assume that even one bottle would NOT be suitable on fasting days – but am hoping you say different! 😉

    Thank you for your excellent blog and research. Absolutely brilliant!

  39. Tiffany

    Dr. Fung, I have been practicing various forms of IF, including most recently one meal a day, and have lost 50 lbs. Before losing weight I was diagnosed as insulin resistant and pre-diabetic.

    Recently, I decided that I wanted to eat lower carb to reduce blood sugar and corresponding insulin response, so I bought a blood glucose meter. This morning my FBG was 84. I am fasting today and went for a long brisk walk and was surprised to find my glucose reading was 92. Doesn’t that mean that it creates an insulin response as well to get the glucose pulled from the liver into the muscles? Last night I went for a walk several hours after dinner and my 4 hour PPG was 92, after the walk it was 79. Should I only exercise after eating then when insulin will be released anyway? Am I unwittingly negating the purpose of the fast (to avoid insulin response) by exercising while fasting? Or perhaps I am confused how this works. Please explain! Thank you!

    • Tiffany

      I have a meter that measures both my blood glucose and ketones and I fast and exercise. In my experience, blood sugars can increase, but so long as they are below 100 my ketones have always kept me in ketosis. When fasting, glucose in produced in the liver. Exercise increases your need for additional energy which is supplied by increased ketones. There may be a corresponding increase need of red blood cells (must have glucose) to carry the additional oxygen required by the muscles as well, so our bodies being pretty smart, produce the extra necessary glucose to compensate.

      Even when my blood sugars are slightly elevated, my ketones also seem to elevate.

  40. Hi there! I’m doing 6 days of fasting in 14 days, essentially, every other day I am eating. I am drinking bone broth, tea, and water on non fasting days. I feel foggy brained and tired, and getting “hunger headaches” which is my biggest complaint because I am a college student and am having trouble focusing; therefore, I just feel like sleeping right now. Any tips?

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