Fasting is the new fad, and if you check numerous
forums where people talk about their fasting experience you’ll find it has helped a lot
of people lose weight. You’ll see people talking about how they
tried all kinds of diets: low-carb, the keto diet, low fat, reduced sugar, all kinds- but
for some folks, none of those worked for them. Then they fasted, and the weight came off. On top of that, they talk about mental clarity,
feeling light on their feet, more agile. You can watch David Sinclair, a Professor
in the Department of Genetics at Harvard Medical School, telling people they should skip meals,
something in the past that was seen as an unhealthy way to live. So what actually happens when you fast, either
doing the short intermittent fasts or the grueling 5-day fasts? Let’s find out. Harvard University is where we decided to
go to find out about intermittent fasting, only because we believe we can trust the school’s
research over some other more dubious health guru websites. Scientists at Harvard, including David Sinclair
who we just mentioned, have done all kinds of tests on rats to see what makes them healthier
or unhealthier. When it comes to fasting, the rats came out
looking pretty good. The results were often the same with any of
the rats on a fast, it would lose weight, and its blood pressure, cholesterol, and blood
sugars would often improve. The U.S. National Institutes of Health agreed
that when rats fasted there were health benefits, including a more efficient energy metabolism. That’s rats, though, not humans. So, what scientists then had to find out is
would humans get the same benefits? Should we give up three square meals a day,
or lots of small meals, and just deprive ourselves of food now and again? Let’s have a look at what happens to the
body when we fast. The experts tell us that when we don’t feed
ourselves for somewhere between 12 and 16 hours our glycogen stores in our liver become
depleted. The body then switches from using sugar as
a source of energy to using fat. If you did a lot of exercise this can also
happen. This metabolic state that happens during this
time we call ketosis, and this brings about changes in the body. Most of us don’t actually reach this state
because we have grown up being told to eat when hungry, don’t go to school on an empty
stomach, or we just put sugar in that morning coffee at the office. Fasting means trying to avoid calorie intake,
although there are some that say a few calories might still keep your body in the fasting
state. That’s debatable, as some say only have
water or tea. As we said, some leading researchers around
the world did lots of tests on rats, allowing some to eat what they wanted and others were
only given food now and again. This is the conclusion we found in one paper
that was published by the National Institutes of Aging. “Emerging evidence suggests that intermittent
dietary energy restriction might improve overall health and reduce risk factors for diabetes
and cardiovascular disease in humans. Our new findings in laboratory animals provide
evidence that similar intermittent eating patterns can enhance the beneficial effects
of aerobic exercise on endurance performance.” You can read a lot of books on why our obesity
crisis happened and the long and short of it all is many people are too sedentary, or
just eat way too much and way too much sugary, processed food. It won’t surprise you that the book “The
Obesity Code” tells people they shouldn’t constantly be snacking and they should try
and eat healthy foods, more veggies, fruits, healthy proteins, and less refined grains,
processed foods and sugar. It’s no surprise that some of the fattest
countries in the world have a snacking culture and a fast-food culture. Still, some people do eat quite well and still
can’t seem to lose weight. It’s as if the body has a certain calibration
and wants to stay at a particular weight. That’s where fasting has helped people. It’s worked where diets have failed. You see, there is some evidence that even
when we restrict our bodies of calories the body thinks oh God, I am starving, and so
slows down and takes what it can from the few calories you put in. Even if you are a big person, if you reduce
calories you might not lose weight because your body goes into survival mode. It slows down its metabolism. If you watch enough Joe Rogan you’ll know
this is an ongoing argument, but what most people do agree on is that fasting seems to
work for most people. But if you look at human studies which had
some people on a plant-based healthy diet and some other doing one day fasts, the results
weren’t much different. Some people lost weight, others weren’t
affected much at all. Then again, there is lots of evidence out
there from people who actually tried fasting and the results for most people were positive. But we’ll get around to that later. Researchers from the University of Alabama
were interested to see if fasting might help people with prediabetes, meaning they were
on their way to getting full blown diabetes. It’s well known that if you eat a ton of
food before you sleep it can increase your chances of getting diabetes. We don’t need to tell you that if you are
very obese because your fingers are hardly ever doing anything other than putting chips,
cookies, all kinds of processed junk into your mouth, you are at risk of getting diabetes. The proof is in the pudding, and America has
a big pie of evidence. In 2018 the U.S. Centers for Disease Control
and Prevention told us that one in seven Americans has diabetes, and while lifestyle is not to
blame for around 5 percent of cases, the vast majority of the remaining 95 percent have
diabetes because of a poor diet and resulting obesity. So, can fasting help? Well, in one study the researchers put prediabetics
on a plan called “early time-restricted feeding.” This meant some participants could only eat
from 7 am until 3 pm and nothing else after or before. The other group could eat between 7 am and
7 pm, a kind of normal timeframe for most people. Both groups actually didn’t gain weight
or lose weight, but those in the 7-3 timeframe showed a drop in insulin levels. They also showed a lower blood pressure, and
another important factor was they just got used to it and showed a decrease in appetite. There is no doubt that this kind of intermittent
fasting has worked for a lot of people, but most researchers do say if you do it also
try and have a healthy diet and healthy lifestyle. Dieting may also help, but the fact is some
people find it easier to just skip meals. Sometimes it’s hard to find healthy food
and sometimes it takes too much time to cook, so fasting is a good option if you want to
try and lose weight without much planning or effort. What about fasting not just for a certain
part of the day, but missing an entire day’s food? The American Journal of Clinical Nutrition
published a study from independent researchers who took a bunch of participants and put them
on this one day a week fast for five weeks. It’s conclusion was that indeed people lost
weight, but they were also hungry during that fasting day. It said perhaps adding one healthy meal in
a fasting day would be better. That’s why you’ll hear a lot about 16
hour fasts, 18 hours fasts, 20 hours fasts. Maybe start with the 16 hour fast and build
up to 24 hours. All over the web there is scientific and anecdotal
evidence that fasting can help reduce a person’s weight and also help people with type 2 diabetes. Some evidence also points to fasting increasing
something called the BDNF protein in the brain, which is why some people claim they have enhanced
mental clarity when fasting. Others say that giving the body a break from
food can help reduce pain and inflammation and also help repair cells. Some studies have concluded that chronic pain
can be eased if fasting is done in tandem with a vegetarian diet, while there is some
quite strong evidence that tells us fasting might help with other chronic degenerative
and inflammatory diseases. We found one paper in which scientists wrote
that fasting might help regenerate stem cells and so could have a positive effect on cancer
patients. Studies on animals show that fasting might
even reduce the chances of getting Alzheimer’s disease or heart problems, but so far these
studies have been done on animals so right now we should say it’s only a possibility
it could do the same for humans. We should say, however, that doctors don’t
recommend pregnant women fast, nor malnourished people, nor people with a history of eating
disorders, children, or women who are breastfeeding. Basically, it’s best to do it when you are
an adult and you feel you need to lose some weight or lower your blood sugar. During your fasts, drink lots of liquids,
mainly water, or tea or coffee with no sugar or milk. You can also work out, and don’t worry,
it’s not dangerous to do that according to the health experts. Some people online said they felt great exercising
on their fast, but others have said they felt weak or got a headache. If you do it, take it easy and see how you
feel. As for longer fasting, say 72 hours, most
health experts say such water fasts are best done when medically supervised. We found studies online which did say such
long fasts have helped people who suffer from hypotension. These fasts can help stabilize blood pressure. We must point out, though, that there have
been cases of people dying when doing very long fasts. In 2010 a woman from Florida died on her 21st
day of fasting, so we really advise you to talk to health professionals before embarking
on a long fast. You will find lots of people claiming that
long fasts, often week-long water fasts, can help your cells regenerate and you become
healthier, but a lot more scientific research needs to be done. Some studies have shown that long fasts have
helped people suffering from cancers, heart disease and diabetes, while also promoting
cell re-growth, but as we said, we really think you should check first with a doctor
and ask them what they think about you doing a fast longer than 24 hours. Intermittent fasting, though, from what we
can see, is safe for most healthy people. Just head to any forum and see what people
are saying about intermittent fasting and indeed you will find scores of people saying
that they lost weight, felt more mentally alert, while after fasting they just didn’t
need as much food as before. As one doctor said online, too, his clients
found fasting a lot easier to do than following a strict diet plan. Looking at forums you will find lots of people
saying things like this: “Yes intermittent fasting is very helpful. I have lost 30 pounds, went from 20+% body
fat to 8% so far from just this March. I have been doing it every day since.” There seems little doubt that many people
lose weight when doing these fasts, even just 16 hour fasts. Most people will eat their evening meal early
around 5, and then get through most of the morning without food. While a lot more research needs to be done
concerning all the health benefits, just reading what people say about their fasts online let’s
you know that fasting does work for most people if they want to lose weight, while many people
enjoy how they feel doing the fasts. Have you tried fasting? How was it for you? Tell us in the comments. Also, be sure to check out our other video
I Did 30 Push-Ups For 30 Days And This Is What Happened. Thanks for watching, and as always, don’t
forget to like, share and subscribe. See you next time.

100 thoughts on “What Happens To Your Body When You Don’t Eat (Fast)”

  1. I think just eating only the necessary amount when you feel the need is the most important thing if you want to maintain your weight. I had no problem maintaining weight when I lived alone but as soon as I lived with my family I gained weight a lot because I had to eat at certain hours and eat more just to clean up leftovers.

  2. Our cloture is so freaking unhealthy that doctors cannot recommenced anything else but to stop eating… indeed sad

    And people are so weak they cannot control calories in vs calories out they have to not eat at all

  3. So you guys regurgitated a lot of results and/or anecdotal evidence but didnt actually explain why fasting helps at all and what is actually going on inside your body.

  4. my opinion is , you should trick your brain . when you're hungry your brain produce hormon called ghrelin if you re satiated your brain produce hormon called leptin .

    so if you're hungry when you re on the way of losing weight, just consume less food but contain a lot of leptin (vegetable , oats , chicken breast etc) . for me i just drink hot water + high protein/ cal milk + oat + cinnamon powder (i know this from my personal trainer a long ago). i can survive days just drinking this when i am hungry. (yes your body asking for eat but your brain said you're not hungry ,so it's safe)

    and it's vice versa if you re on the way of gaining weight. consume more caloric food that easier for body to absorbs (liquid foods etc). just make sure you gain muscle not fat (caloric dense food)

    i know it's not easy but it's do able. if it's easy everyone already on their best shape .

  5. I’m doing intermittent fasting for 2 1/2 years now and I love it it’s practical easy and it fits to my lifestyle. I just skip breakfast and eat 2 big meals and a snack wich isn’t a meal but not as small as a „normal“ snack.

  6. Dr. Rudi has full fledge guaranteed way to lose weight, it always work.

    "Eat less"

    Of course eating less won't work unless you actually

    "Eat less"

  7. Tea or coffee is not allowed during ''fasting period". Anything but water. 😉 Watch Dr. Panda or Dr. Rhonda Patric to find out more about this.

  8. If yous wanna know about fasting in depth the health benefits the fact our ancestors use to do it and what ketosis actually does in comparison to glucose then check out a channel called what I've learnt who had many great videos on this subject

  9. I am trying it out now for the first week, i start eating from 10.00 right after i go to the gym (weightlifting 1 to 1,5 hour), then eat again and last meal around 18.00 and last a caseine proteïne shake at 20.00 so a 14 hour fasting. (Total calories are aprox 80% maintainance)
    Hopefully i get fat% under the 10% now😁

  10. I'm convinced that fasting brings us physicly and mentally closer to the agile and sharp "hunter-gatherer" uber-primate that we are meant to be! So don't eat to much. Just eat healthy and move a lot. You'll see how things change for you!

  11. Gaining fat is so much harder after I fasted. Stomach was small so only little food was enough. The routine becomes your religion overtime, so practice and consistency is the key.

  12. Here's some pro tips:

    Don't force yourself by not eating anything at all, have some light breakfast and then try not to do too much activities for the rest of the day. Do the fasting at your day off so you can spend the day sleeping.

  13. You're talking about so much study's and university things but there aren't any studies in your discribtion… explanaition?

  14. Im on a mandatory 3 day fast right now. Only public water from my apt tap, and the only movies i watch are ones i rent out from the library for free. Cmon pay check i need ya!

  15. Muslim people fast for a whole month from dusk to dawn. It is called Ramadan. It is around 12-16 hours per day depend on the time of the year, and the country, but in a few countries the period between dusk to dawn is huge, it can lasts to 23 hours per day. The difference between fasting, and Ramadan is that you can't even drink any kind of water, or even smoke cigarettes, or any kind of smokes.

  16. Who cares I’m not fasting , if you have to go without food you may as well binge on some Pablo and enjoy yourself. Two weeks will fly by with little effort

  17. first i did keto for 3 weeks then started fasting, quit sugar and processed food. this fixed my gut microbiome and liver so i dont feel painful hunger pangs, started with 8/16 then 4/20 then now 1/23 or 2/22, sometimes 48 hr fast

  18. Once a year, for a month, every day, I eat at 5 am, Then don't eat OR DRINK for the rest of the day until 5:30 pm. No water no food.

    This is called Ramadan Fasting.

  19. The state is definitely not called “Ketosis”. Ketosis is when your body doesn’t have any carbs for days and your liver produces ketones for energy. False information video.

  20. i lost 73 pounds in 6 months because i was fasting, i ate every 24 hours, i been obesse all of my life, and now i'm feeling so happy 🙂

    It's worth it guys, try it 🙂

  21. we muslims fast for 1 month(in ramaddan) without eating or drinking from sunrise to sunset .
    so watch "the meaning of life muslim spoken". Thank you

  22. why you talking about America America and America. Go check out ISLAM. (Bigbang, fasting , mentalhealth everything ISLAM showed 1400 years ago in Koran)

  23. I did this for some time and it felt great. I even played a football match in a 16hs fasting and felt and played really well. I definitely lost a few pounds too but Im not fat at all so that was not like the only thing i wanted to do

  24. It also depends on how often you fast and for how long. Ever heard of Ramadan? I know it's not for health, but if you strictly look at the eating schedules, and disregard the purpose, then you see the results.

  25. I agree, it definitely helps from my opinion. I prefer the 8/16hours ratio and on a few separate days out of the month I will do the 20-18 hour fast with a light soup or smoothie afterwards.

  26. Do a video on the pros and cons of crossfit. Also I've always done a 16:8 since i was like 20… 46 now. Didn't know the benefits it was just based on my activities. Love the videos!

  27. Ayurveda and Yogic science has been insisting “fasting” since time immemorial! Indians have been following fasting as a religious obligation. Nothing new in the video except for some scientific details and reasoning 😏

  28. In religious practise once a year for a whole month of Ramadan we Muslims fast for health benefits and to experience the starvation on the poor for support plus receiving God's forgiveness.

  29. Hmmm… I wonder if it makes sense because it’s only in modern days that we have food available every day. Evolutionarily speaking, our bodies are probably wired to deal with short periods of not having found any food.

  30. I am a westerner who has lived in Asia for over a decade. It's funny how (us, westerners) seem to be so behind when it comes to health. That said, it is funny how westerner-influence has increased health issues in Asia… The world is truly round.

  31. I've fasted at most for 22 days, drinking only water and salt. I eat a meat-only ketogenic diet. Down 200lbs since Feb 2017. It works.

  32. Has anyone doin water fasting for 30 days while doing testosterone injection to retain the anabolic for the body?

  33. i think maybe i could resist the temptation of eating, but can you make a new video on how to keep your stomach quiet during a lecture please?

  34. I tried intermittent fasting when I was 90kg. It was difficult the first week but then i got used to it. I was also trying to gain muscles and loose fat so I ate 3000 kcal daily and fast for 16hours only for 3months. By then I was 70kg with more muscles than before according to my test…. After that i stopped fasting and regret breaking that life style.

  35. There doesn't seem to be a lot of information on this online, so I just wanted to tell people, it's very helpful to take electrolytes if you work out in a fasted state, since you won't be able to replenish it from food. If you lose too much electrolytes, you can feel cold and lack energy after your workout. That's what happened to me. Although one cup has 32 calories, if you work out, coconut water is the best since it's one of the best sources of potassium. Don't consume when fasting without working out

  36. I've tried intermittent fasting in the past, and although it works for some people, I found that eating 4-5 small, whole food meals worked best for me, only eating about 400-500 calories per meal. I do however include vigorous exercise into my routine. It's all about trying everything and see what works best for that specific person, because we are all unique.

  37. Last time I did a fast I lost so much hair, most of it grew back when I stopped but some remains and I just gained the wight back

  38. i remember when back in the 80s carbs were glorified as the miracle… now we have a generation of diabetics….

  39. Research has proven that RMR does not go down when using IF…makes sense if you were a caveman and still needed energy after not eating for days…otherwise they’d stay in the cave and wait for ‘skip the dishes’

  40. i do omad… one meal aday… i did keto for a year the first 5 months,, lost 46 lbs… now day 3 of carnivore…. 4 lbs in 3 days,,, now im back to losing weight…

  41. Is it the fasting ( lack of food nutrients for a period of time) or fasting as in the lack of putting all those chemicals, preservatives, dyes, powders, anti caking agents in your body which is trying to filter them and giving your body a much needed break that in turn gives you mental clarity, extra energy, weight loss, less inflammation, lower blood pressure, etc.?
    Treat yourself and fast. The human body was never designed to handle the amount of sugar we eat in a year. The whole reason 10,000 generations of your family tree has survived to get you here was not due to any man made sugar. Everything was provided for them to survive and thrive with natural sugars in berries, apples, fruits, honey, etc. Give yourself a break from all those trace herbicides and pesticides in the food you have been eating. ( a recent study showed cereals and oatmeal ( 17 out of 20) to have the highest concentration of pesticides in them. Just change 1 meal you eat that you never really liked, to a healthy version that you love and technically you have started your diet. Now go to meal number 2 and so on. One at a time.

  42. I've been doing intermittent fasting since end of August, and have lost 41lbs so far. This is the first time I've worked on losing weight that I haven't hit a plateau (yet anyway). Also, the weight is coming off my stomach and face, which are literally the last places my body will ever take weight from. I feel like my body would rather I lay down and die than give up weight on those parts of my body, normally. I don't know why.

    Additionally, and I wasn't expecting this at all, other than the added mental clarity that was mentioned, my immune system has improved incredibly significantly. At work I come in contact with lots of people all the time, and usually when someone is sick I would get their cold. Now, everyone around me has been sick, people at work, people at stores coughing, family, etc. and not even a sniffle from me.

    It's been easy, and it's given me extra time and one less worry. I eat as soon as I get up, and then whenever I am able to eat lunch, and then I'm done for the day. It is so freeing. The hunger for dinner went away after just one week.

  43. Don’t waste your time on this video …. same BS that turned us into a fat nation mixed with bits of truth … shame!

  44. I started OMAD about 2 years ago (bacon, eggs, cheese and an avocado for dinner), black coffee in the morning and then water. I lost a total of 30 lbs within three months and then another 10 over the next three. I have fluctuated 5 to 10 pounds here and there, but I cheat sometimes, I like puff pastry wrapped foods and beer. LOL But when I go strict again, the pounds drop like water off the back of a duck.

  45. Simple truth across all species: reduce food intake by 30% and increase average lifespan by same. Works for all forms of life. Hmmm.

  46. Fasting is known concept in india.most of the People do 24hrs fasting for every 14days (11th day from full moon day and 11thday from no moon day.

  47. I just finished a 4 day water fast for the first time. The first day I had a terrible headache but I really wasn't hungry. Each day the headache lessened. On day 2, I woke up completely pain free! I wasn't stomach growling hungry until the end of the third day. I didn't have much energy but my clothes are looser. Day 4 I felt a little weak but noticed that the chronic pain in the muscles of my back almost completely healed. I will definitely be doing a water fast a few times a year. Normally, I intermittent fast anywhere from 18 – 22 hours each day.

  48. I tried this intuitively and found it works great. I simply just stopped eating late in the day to give my digestion system a break, especially while im sleeping. Last meal for me is around 3pm-4pm. I lost 42 lbs so far ( from 234 to 192) and feel better than ive felt in my life. My advice, Keep it simple and make it a life style change.

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