Lose weight using intermittent fasting

Do you want to lose weight? I’m currently updating my page with the most important tips on How to lose weight. The page is structured so that you can start at the top with tip #1 and then keep going as long as you like – perhaps you only need one or two of them.

Today it’s time for a new piece of advice at number 14. First a quick recap of all the earlier tips:

Choose a low-carb diet, eat when hungryeat real foodeat only when hungrymeasure your progress wiselybe patientwomen: avoid fruitmen: avoid beer, avoid artificial sweetenersreview any medicationsstress less and sleep moreeat less of dairy products and nuts… and supplement vitamins and minerals.

So there are many things to consider before moving on to this thing, but don’t let that fool you. This is one of the most effective weapons available to lose weight. It’s perfect if you are stuck at a weight-loss plateau despite “doing everything right” – or to speed up your weight loss.

Use intermittent fasting

This super weapon is called intermittent fasting. It means exactly what it sounds like… not eating, during a specified time interval. Here’s how to do it:

Recommended first option – 16:8

Probably the most popular option is fasting for 16 hours (including sleep), which is usually easy to do on an LCHF diet. It only requires trading breakfast for a cup of coffee (or some other non-caloric fluid) and having lunch as the first meal of the day. Fasting from 8 pm to 12 noon – for example – equals 16 hours of fasting.

Of course there are many other variants of intermittent fasting, but this 16:8 method (16 hours of not eating, 8 hours of eating during a day) is the one I recommend as a first option. It’s effective, easy to do and does not require counting calories.

You can do a 16:8 fast as often as you like. For example twice a week, or on weekdays only… or every single day. The more often you do it, the more effective it is.

In fact on an LCHF diet some people spontaneously fall into this habit, as their appetite is reduced (see weight loss tip #4, eat only when hungry).

Other kinds of intermittent fasting

There are many other options. Basically the longer periods are harder to do but more effective. Here are two more common options:

  • Fasting for 24 hours (often dinner – dinner) once or twice a week. Effective and can be surprisingly easy to do, especially on an LCHF diet.
  • The 5:2 diet. Eat as much as you need to feel satisfied 5 days of the week and then eat calorie-restricted on two days (500 calories per day for women, 600 calories for men). I don’t recommend this as it requires calorie counting and extra planning, but some people still find they enjoy it.

What about eating when hungry?

Doesn’t advice on intermittent fasting contradict the advice to eat when hungry? Yes it does, somewhat.

I recommend eating when hungry as a first option, and I recommend always eating until you feel satisfied at meals. But if this is not effective enough then intermittent fasting is a very effective addition. Remember – and this is crucial – that between fasting periods you’re still supposed to eat until satisfied.

Intermittent fasting is not the same thing as obsessively counting calories and starving yourself 24-7, i.e. “caloric restriction as primary” (CRaP) diets. Starving yourself is a recipe for misery and failure.

Intermittent fasting is about eating all that your body needs… while still allowing it to sometimes briefly rest from constant feeding.

What’s acceptable to drink during fasts?

During a fast you can’t eat, but you should definitely drink. Water is the drink of choice, but coffee and tea are also great options. During longer fasts it can be wise to add a little salt too, or drink bouillon.

Anything you drink should ideally be zero calories. But it may be acceptable to cheat by adding a small amount of milk in your coffee or tea – if you absolutely need it to enjoy your drink.

What to eat between fasts

So what should you eat when you are not fasting? Well, if your goal is to lose weight I suggest following all the tips above, including eating an LCHF diet. Combining this with intermittent fasting is a great combination.

On a LCHF diet your hunger is reduced and it’s much easier to do a period of fasting. Also, your fat burning is already very good – so when fasting you’ll easily burn lots of fat.

So, while on an LCHF diet the fasting periods become both easier to do and more effective. 1 + 1 equals 3.

Who should not do intermittent fasting?

Intermittent fasting can be a great idea, but not everyone should do it:

  • If you are addicted to food or sugar then intermittent fasting will increase food cravings and increases the risk of a relapse… so be very careful. I recommend always eating when hungry.
  • If you are totally stressed out or sleep deprived then take care of that problem first (see weight loss tip #11) or fasting may be too stressful for your body.
  • If you are on any medication – especially insulin – the doses may need to be adjusted when fasting. Discuss it with your doctor first.
  • Growing children, pregnant women and breastfeeding women should not do longer fasting periods, as they have an increased need of nutrients. I recommend eating when hungry and using the 14 tips above if you need to lose weight.


For more on fasting check out our material with our top fasting expert, Dr. Jason Fung:

What is Fasting? – Dr. Jason Fung
How to Maximize Fat Burning – Dr. Jason Fung
How to Fast – The Different Options – Dr. Jason Fung
The 7 Benefits of Fasting – Dr. Jason Fung
The Top 5 Myths of Fasting – Dr. Jason Fung
Breakfast! Is It Really That Important? – Dr. Jason Fung
The Perfect Treatment for Weight Loss and Diabetes – Dr. Jason Fung
Ask Dr. Jason Fung

All 18 tips about weight loss on the page How to Lose Weight.
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  1. 2 comments removed
  2. A. C.
    I’ve been on for 4 days now. I’ve been binging between the 8 because I didn’t read and understand the fast better, but however my Sleep and energy is pretty constant. Now I’m focusing on the low calories.
  3. 9 comments removed
  4. Aj dimal
    I have a question for 16:8 pattern in 12 noon to 8pm you can eat lunch and dinner in that period of time right? Or in that 8 whole hours you can just eat one meal?
    Reply: #164
  5. Will
    Typically people eat lunch and dinner in the 12 noon to 8pm window... to start with you might also have a mid afternoon snack too as your appetite adjusts.
    I fast from about 5.30pm until about 9.30am.... but thats just what works for me. I did loose about 20lbs though which I'm pleased with and feel overall better, sleep better etc.
    Replies: #175, #189, #198
  6. 1 comment removed
  7. Nita
    I am going to try this out soon..wish me luck:)
  8. Mark
    Good Luck Nita! I have been on it for a week now with great results. Always good to check with your doctor. I do not have to take any medications and in good health. Already excited about getting sculpted. Definitely do the 12pm to 8pm to eat, eat healthy and if you are working out, make sure you put enough good food(fuel) in your body.
  9. L.A
    hi! if i do the 16:8 intermittent fasting and my 1st meal is at 2pm and last meal is at 10pm, can i drink water after waking up at around 11am?thank you
  10. Anne
    HI L.A. You can drink lots of water on IF -- it is recommended.
  11. Charlie
    I’ve been practicing 16:8 for 2 months and after a week my cravings disappeared and I’ve lost 13 lbs. Not to mention, I feel great! Best diet I’ve ever tried and I eat whatever I want. Except I have celiac disease and natural eat low carb, but still enjoy rice and gf noodles or potatoes.
  12. Karen
    I've been doing the 16:8 for about 9 days now, in conjunction with the Keto Diet. It actually works well I think. The only time I get hungry is the last 2 hours (I do 11am to 7pm) between 9 and 11. I figure it doesn't hurt me to be hungry for 2 hours. I bring my lunch to work so there is no danger of me binging on something I shouldn't. I also work out in the morning on an empty stomach (well I do drink 2 cups of coffee first). I feel great and the heartburn I had at night is starting to go away. Pants are feeling looser also.
    Reply: #196
  13. MissPriss
    Is it productive to fast M-T only?
  14. 1 comment removed
  15. Elssy
    I’m trying this on Monday hope it work it for me
  16. CJ
    What was the length of time that you lost the weight?
  17. Pinkkky
    I wanna do this but im a little confused! !!! So you not suppose to eat for 16 hours?? I just need more explaining .... Like 8-noon THE NEXT DAY I DONT EAT,right? Then after that i eat something then dont eat again for 16hrs? RIGHT??? Somebody plz answer
    Reply: #177
  18. Anna
    Hi! So typically you want to sklip breakfast and eat from noon to 8 pm :)
  19. 1 comment removed
  20. Pam
    Hi can you please advise if you csn have fruit between meals
  21. 1 comment removed
  22. Ana
    Would it be ok for you to drink a zero carb protein if you do the 16:8 diet after your workout? or would it have to technically count as your "last meal" and than start counting from that time forward for the 16hrs?
    Reply: #182
  23. Pinkkky
    when I wake up I skip breakfast and EAT AT NOON - 8PM...... thats the part im confused with...... So do I eat every hour starting from noon to 8pm then STOP for 16hours? Then do it all over again?Right lol
    Reply: #183
  24. Peter Biörck Team Diet Doctor
    Hi Pinky!

    noon- 8 PM : Eat 2-3 times (not every hour) after your choice.
    8PM - Noon: You eat nothing.

    Replies: #184, #191
  25. Pinkkky

    Thank you.... Ok i understand now but I thought it was you dont eat for 16 hours! !! 8Pm - noon is only 4 hours! So now im a lol confused lol can u explain that part. Thanks

    Reply: #208
  26. 2 comments removed
  27. Pinkkky
    Thank you.... Ohhhh ok I understand....
  28. Gwen
    What's the minimum amount of calories a woman should consume during the eating hours. I have a habit of not eating enough calories so need to track to ensure I don't slow my metabolism.
  29. George Giles
    I am confused, what was loose ?
  30. Satin
    I was doing this diet for 4 days and I put on 1.5 kg
  31. Seah
    Hi Peter !

    Your Reply
    noon- 8 PM : Eat 2-3 times (not every hour) after your choice.
    8PM - Noon: You eat nothing.

    My question : (8PM - Noon: You eat nothing)
    The Next Morning , Can I drink a cup of 100% Cacao Powder + Water + some Chia Seed ?


    Reply: #192
  32. Peter Biörck Team Diet Doctor
    Hi Seah!

    Normally the idea with 16:8 fasting is that you consume 0 calories during 16 hours and all calories you need during the 8 hour eating "window".

    So you should drink only water in the morning. ;-)

    But why not try your idea and see if you get the results you would like to have anyhow.

    Hi Peter !
    Your Reply
    noon- 8 PM : Eat 2-3 times (not every hour) after your choice.
    8PM - Noon: You eat nothing.
    My question : (8PM - Noon: You eat nothing)
    The Next Morning , Can I drink a cup of 100% Cacao Powder + Water + some Chia Seed ?

  33. Marianne
    Hi! I’m doing the 16/8 method since 2 days. My question: right after am done with my first meal (at 12) I have a heavy feeling in my stomach (as if my stomach wasn’t appreciating the food arrival) and pressure feeling in my thyroid area (am taking thyroid supplements since years). I eat the same (whole, balanced diet) I was eating before starting this program. I also have head ache right after having that meal ... any idea what happens and what I can change? Thanks!
  34. Ryan
    Can i still take supplements vitamin tablets creatine, pre work out etc at any time or do i have to take them within the 8hour window
    Reply: #195
  35. Peter Biörck Team Diet Doctor
    Hi Ryan!

    Normally you can take stuff that contains 0 calories (or almost zero :)

    Can i still take supplements vitamin tablets creatine, pre work out etc at any time or do i have to take them within the 8hour window

  36. FattyMatty
    Hi Karen. Me & my misses just started KETO...my question is did you start the 16/8 fast right away?
  37. Dianne
    Can I do this form of dieting 4 days per week and then just have a balanced diet on the alternate days? Dianne
  38. Sophie

    Did you eat restricted calories or healthy diet during "feasting" period of eating? is that why you lost 20lbs? I'd love to lose 20lbs, and I can do 16:8 easy I think, but I'm under the impression that you can eat lunch and dinner of your choice (high carbs?) in that duration, correct? or incorrect?

  39. TearDrop
    doing the 16/8 fasting as of 8/23/2018 work great for me ! last meal at 7:00pm to 11:00am mon- Fri already lost 1 pound ! If I get hungry before 11 I drink water and I also drink morning coffee.
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