7 Day Water Fast: Health and Weight Loss?

by 447 · October 15, 2013 at 4:11 AM

I am doing a seven day water fast because I want to clean out my system! I wouldn't have a problem with losing a few extra pounds to be honest haha. My question is.. around how much fat would I lose in seven days? Also, will I gain it all back with a low carb paleo diet?


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29 Replies

4171 · June 13, 2011 at 3:11 AM

I don't know about fat loss but I'd be concerned with losing lean muscle doing that.

11049 · June 13, 2011 at 5:26 AM

I do 3-5 day fasts every few months and have for years, for spiritual reasons. I have never noticed any obvious loss of muscle mass/strength, infact just the opposite I come away feeling stronger esp spiritually and emotionally. If one's body is healthy and you have been eating properly for a long time long fast are a non-issue.

3317 · June 13, 2011 at 3:25 AM

I've done 14 days on water. I was 19 years old (16 years ago) and I was doing it as a sort of spiritual cleanse, rather than a weight loss diet. I'm sure I lost weight, but whatever weight I lost was most likely water and later, muscle. I personally believe deeply in fasting -- both for spiritual and health reasons -- It puts you in touch with your body in new and unexpected ways. But I don't think it's a good weight loss strategy by any means.

Eating nourishing food during the day and then fasting in the evening and through the morning can give you the best of both worlds.

But if you want to learn a hellofalot about your body, how it functions, what it's limits are. If you want to experience the euphoric chemicals that your body is capable of producing all on it's own and have an interesting trip that's outside of normal human experience? Go for it. Just don't expect it to be a solution to weight problems. ;)

15964 · June 13, 2011 at 4:14 AM

I'm not into fasting as a way of cleansing. The liver needs protein for proper detoxification as well as some cruciferous veggies. If I wanted to do a detox I'd add in some light proteins -maybe a poached egg or two, steamed broccoli and milk thistle tea.

This is a well respected clinician who has this to say on the subject: Fasting for more than a day or two without protein in your diet can shut down primary Phase 1 and Phase 2 liver detoxification function which can stay impaired for months.

I highly doubt anyone would be able to tell you how much fat you will lose. Good luck. Keep us posted.

1153 · May 14, 2012 at 4:52 PM

It takes more than a week to lose muscle,the body fights very hard to retain it.

30 · March 14, 2012 at 12:19 PM

It's funny reading comments from how bad fasting is for you, before I did my first fast I spoke to a dietician friend of mine, she said it's really bad for you, don't do it, luckily I didn't listen to her. Our bodies are designed to go without food for 40 days if needed, how could a 7 day water fast do any real damage to a healthy person. Our ancestors frequently went without food for days and weeks, that's why we store fat in the first place, the body will eat fat first, it's only when you are out of fat on a fast that you are in trouble. If you fast beyond the point of your fat reserves the body will start consuming your muscles and organs, and tumours, that's why fasting can sometimes cure cancer (emphasis on sometimes).

In any case everyone in the west should try fasting 5+ days, at least once in their life. It's a interesting experience. And it doesn't kill you.

30 · June 13, 2011 at 4:09 AM

Assuming you did no sort of exercise during that time a generic calculation would be 7 x your BMR (Basal Metabolic Rate) / 3500. For me 7x1800/3500 is 3.6 pounds. No way to really know for sure but that is about as generic as you can get. I suspect you will actually lose substantially more as your body starts eating itself.

A better way to do this is to simply cut out all carbs or limit yourself to < 20g of carbs a day. After two days or so your body will begin using fat for fuel and you will lose weight. It's Atkins induction. Search Ketosis for more info on that.

Fasting for 7 days is pretty extreme in my book. I generally fast 1 day a week. On that day I drink green tea to eliminate my hunger. It works. I wouldn't attempt 7 days without some professional advice myself. I too would be extremely fearful of muscle loss and I work too hard to gain it to let my body eat it.

Try a day here and there to see what it's like. I am afraid 7 days may be quite a shock to your system but hey! I'm not you.

Good luck!

260 · June 16, 2012 at 7:25 PM

During my first 7 day water fast (about 2 years ago) I lost about 20 lbs (I had about 60 lbs to lose total). On breaking the fast everyone recommended juice and fruit because it isn't too hard on your system . . . I did the opposite. Moderate amounts of protein and fat for a few days and then increased the amounts back to my normal calorie intake. I gained back about 4 lbs. (which I assume was mostly water) and then continued to lose weight, because I stayed low carb Paleo. I now fast once or twice a month for a day or 2 (especially if I have a high carb day or two when traveling) - and it works well to push me quickly back into ketosis.

The other thing I did that really helped was to go low carb for several days before starting the fast. I basically did Atkins Paleo for 3 days (until I was solidly in ketosis) - I then started the water fast - and basically didn't feel hungry at all during the whole 7 day fast (just the mild "I could eat something" feelings that you will feel the whole time you fast).

Sidenote: The weight you lose in the first week is really going to depend on how much weight you have to lose. If you are 100 lbs over weight, you can expect to lose 25 lbs in week 1 - on the other hand if you are only 25 lbs over weight, you will probably lose more like 7. It just depends on your body. If you are near your goal weight and trying to take off the last few lbs then just be careful you don't go to far . . . when you run out of body fat and the major hunger returns you MUST begin eating again! Good luck!!

4612 · May 14, 2012 at 1:26 PM

After water loss, some protein loss, once you hit ketosis, it will mostly be fat loss, but some continued protein los. I have done several 5 day water fasts and I lose the same amount of weight like clockwork whether I start at 126 or 136 - 12.6 lbs. I am 5'4.5", female, age 30, pear shaped. And it does stay off, just be sure to break it gently with bone broths and soft cooked vegetables if you are trying to avoid fruit sugars, or some diluted juices and watery fruits if you're not avoiding sugars. If you go and have a steak right away you will be rushing to the bathroom within 30 minutes! As soon as you have any solids you will, so just plan to break your fast at home and take it slowly!!

Water fasting can be super trippy - time slows down, you feel weak but inspired in weird ways. If I am in a rough patch in life it actually really helps me find my footing, mentally. I guess that is why many do it for spiritual practices. Good luck.

1383 · March 14, 2012 at 4:42 PM

If you haven't yet, you should probably read this critique of the "cleansing" idea: http://www.marksdailyapple.com/are-detoxes-and-cleanses-safe-and-effective/#axzz1p6cbWse1

10 · June 18, 2012 at 8:04 PM

Today was my first day to fast,i had never fasted before,I hope to do a 7 day fasting for personal reasons.The problem that i had today was that i was thinking about food the whole time but i managed to get by until now im going to sleep i had 3 litres of water only.I hope to stick to it because i really need to do this........wish me luck!

55 · May 14, 2012 at 1:07 PM

You will burn mostly fat. Your body will metabolize SOME protein to convert to glycogen. Your brain needs a few grams of glycogen a day to run, it can get most of it's energy from ketones. Metabolizing protein does not necessarily mean muscle. From what I've read, your body will convert any damaged cells to glycogen first. Also, Amino acids can be stored in fat cells, so your body may be able to convert any stored amino acids into glycogen.

5351 · December 10, 2011 at 3:32 PM

Depending on what you were eating a week before and a week after, you'll likely lose around 10 pounds, and regain half of that if you're sensible. Keep an eye on your measurements as well and you'll likely find it's pretty much all going from your belly. There's a possiblity of some minor catabolism of the muscles, although if you've not fasted before you probably have plenty of junk to feed off, and it's much easier to regain muscle weight once you've already built the cells once. Plus all the protein in your digestive enzymes which are no longer needed etc. - obviously this necessitates a certain caution on reintroducing foods, bone broth and other probiotics are best. Personally I don't notice any drop in strength - it is advisable to get one strength session in during the week if that's a concern. Hunters certainly didn't lie in bed wasting away if they were short on food.

All in all, the net fat loss isn't likely to be massively spectacular, and could likely be achieved easier in the same time frame, but the control and self-awareness it gives you makes regular IF a, erm, piece of cake.

26 · September 26, 2011 at 8:43 AM

Actually water fasting can be very beneficial for long periods of time. A person can go around 30 days without eating, and a person can only go three days without water. 7 days is not a long time for a water fast, and is not extreme. So I do not know why some of these people are freaking out so much. After day 2 or 3 your hunger pains will be gone, and the fast will make your eyes clearer, and eliminate a lot of built up toxins in your system. The last time I did a 7 day waterfast I lost 11 pounds, even though it was mostly water weight.

0 · October 14, 2013 at 9:16 AM

see you are not going to lose weight, it is only a water weight which will be regained as you start eating.

0 · October 13, 2013 at 10:29 PM

for more info about Water Fasting Weight Loss :


0 · October 13, 2013 at 10:28 PM

for more info about Water Fasting Weight Loss :


0 · August 30, 2013 at 6:40 AM

Fasting is wonderful!!! I hope you enjoyed your results. I did a 14 day fast and lost 32 pounds. It was quite amazing. I never felt healthier, clearer or better in my life than during the fast. Another thing I realized is that EVERYONE HAS AN OPINION... and the only people who will support your fast are those who are advocates for natural healing, and yourself. Do not look to your friends, family or co workers for support... first off... you won't get it. Secondly, they will all tell you how starving yourself is not the way to lose weight... no matter how many times you tell them its for your health and how great fasting is... and how people have cured their fibroid tumors, become fertile again, reversed disease and repaired their bodies by allowing it to do what God designed it to do... heal itself. Another thing I learned while fasting is that people are horribly addicted to food... they literally cannot stop eating. We are always planning our next meal. We are educated and tricked into believeing we need a lot more food then we do our entire lives. I let my kids become pickier eaters and i also stopped making them finish their plates. When you're body says no, listen to it!!! During my fast, I did not even desire food. I just started Nother fast and I am excited :-) and super happy to be doing this again... I think 30 days is good this time if my body is agreeable. Anyone considering a fast, I highly reccomend it if your health permits... but if you need doctor supervision, I recommend not a general medical doctor but a local naturopath who is familiar with fasting. A medical doctor will not recommend such a radical thing... whatevers wrong... they got a pill for that .

0 · August 26, 2013 at 4:44 AM

Hi guys! I'm a nutritionist and completely recommend 3 day water fasts for beginners and 7+ days for anyone wanting to try it again. The body does NOT eat away muscle until fat stores are extremely low. The body stores fat for the reason of periods of time without food. Think back to your ancestors who either had to hunt or gather food.. Generally the body builds up its fat supplies for winter when food is scarce. I'd also recommend a raw vegan diet to break your fast, mainly anything that will be gentle on the digestive system like juices or fruit. Putting animal products or processed foods into your body will completely reverse the point of a fast.. Most toxins stored in our body's are the result of over consumption of meat and dairy products and foods that contain preservitatives. I have completed a 40 day fast before and will say the feeling you experience during it and quite amazing really. You have more energy, your skin clears up, your mind is clear and your digestive system works a lot better after the fast. Sometimes our body's need a break to gain back homeostatis. Hope this helps :)

0 · June 08, 2013 at 6:37 PM

During the first day or two your body will use muscle for energy. After about 2-3 days of water fast your body will go into ketosis. During ketosis your body will burn fat for energy. Usually the most weight is lost in the first few days.. Most of that weight will be water weight. Normally after that you will lose about 1-2 lbs of fat a day but it may vary from person to person. Note that your stomach will shrink and your metabolism will slow down. How you break your fast is most important to maintaining weight loss. Break your fast with low carb cooked veggies(this will stimulate a much needed bowel movement). I don't recommend juicing if you are trying to keep the weight off because juicing removes all fiber (smoothies are okay). Don't over eat. Slowly move back to eating meats. HTH!

72 · June 06, 2013 at 8:32 AM

Hey It require more than week to lose weight. Be conscious. There are other detox diet available such as juice cleanse detox diet. You can get your weight back by eating paleo diet.

0 · April 09, 2013 at 4:51 PM

Done over 30 days worked hard the whole time construction and exercise, did not loose any muscle at all in fact got more muscle strength, and tone that has stayed with me for over 20 years. Fasted for shorter periods and prayed , tuned into and developed an ear to hear what God is saying. he's always speaking if we learn to listen.

0 · March 22, 2013 at 1:13 PM

I am day 3 into a water fast and it is the first water fast I have ever undertaken. I honestly have to say the first 2 days weren't very difficult at all, and only now am I feeling the detoxing side effects which can only be the toxins being released from the burning of fat. I have done several detox diets and liver cleanses, however none of them have given me the sense of calm that I seem to be feeling that just water seems to have.

Listen to your body and not all the differing opinions, and especially not to anyone that hasnt actually undertaken a fast. Being truthfully honest, it doesnt matter what someone has studied or is telling you; if they arent speaking from experience then its a bag of shit. Speak to people who have done it, they will give you a closer answer to what you'll experience than anyone else.

I once met a guy who would dry fast (nil by mouth) for 48hr every month. He said it was the fastest way to purge the toxins that built up in his body and gave him peace of mind that his body was clean. He had been doing it for 15 years, and hadnt gotten sick for that period of time - I was mind blown. GIve it a go, then you have your own experience.

0 · January 05, 2013 at 3:33 AM

People are coming on here asking about how much weight you can loose. we all understand there are risks but that's not what there asking. its their body and they will do as they plz. its not a big deal to fast a couple of days. instead of the negative responses can you just answer the question? are any of you doctors ??

16 · December 10, 2011 at 2:03 PM

Actually, contrary to all the negative responses on here, a lot of credible doctors and nutritionists say doing a 40 day fast once a year is extremely good for your body. I'm 19, and I'm about to start a 7 day water and juice fast, for spiritual reasons, but also I am looking forward to the physical cleans that takes place. After 3 days in a fast, your digestive system essentially shuts down, you stop feeling hungry. That's the point when your body starts eating itself for energy. How much weight you lose really depends on how much energy you require in a day, and how much fat you have to lose (those two go hand in hand, but I still wanted to mention this). If you have a lot of fat and a lot of muscle, your muscle will increase the amount of energy your body needs to burn in a day, and the first place your body goes to when there is no food in your stomach is to fat storage. Your body doesn't consume much, if any, of the muscle on it until it runs low on fat. So, if you have more than 20 pounds to lose, I wouldn't expect to lose any muscle during this relatively short (compared to a lot of people) fast.

8 · November 17, 2011 at 6:28 AM

People who never go a couple without eating would say your crazy for even doing a 3 day water fast. Everyone is used to eating and eating and eating. People think if you don't eat anything in one day your stomach is going to explode from eating itself. That's why china is a hell of a lot smarter than us. We don't know shit. People don't even know that there's chemicals in flour and bread and etc that makes you fat. Yeah, people would read this and say that's not true. They're the dumb ones lol. That's why america has a little more than 2/3's of our population are overweight and I'm just talking about the adults. I did just a two day fast and I didn't feel different after it then I did before it. It's your body. Don't get advise from people that can't tell a donkeys ass from a hippo. Go through the experience yourself and see what happens. Let everyone else be fat and die of heart attacks.

-2 · December 24, 2012 at 5:16 PM

im 12 years old i fasted for 5 weeks( i finished it last week) it was amazing i was obease before, i was 13 stone, in 3 weeks of water only i lossed 7 stone so now i weigh 6 stone which is a bit under weight but i am so confident and i have kept it off!!! i recommend it to anyone how od young big or small.... YOU WILL FEEL MUCH MORE CONFIDENT....!!!!

-2 · November 09, 2012 at 5:37 AM

Water fasting can be super trippy - time slows down, you feel weak but inspired in weird ways. If I am in a rough patch in life it actually really helps me find my footing, mentally. I guess that is why many do it for spiritual practices. Good luck.Des Moines Mixed Martial Arts

935 · June 13, 2011 at 3:18 AM

this is about the dumbest thing i have ever seen. unless you want your heart, a muscle, torn apart along with the rest of your lean mass as your body will take the aminos it needs. eating good food is the only healthy way to lose weight and my suggestion is following a strict paleo diet of vegetables, some meats and good fat. you simply cannot starve yourself and i dont understand why anyone would fast for more than 24 hours.

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