Science Investigates: Fasting vs. Calorie Restriction?

Cristina Goyanes
by Cristina Goyanes
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Science Investigates: Fasting vs. Calorie Restriction?

People are always on the lookout for quick and easy ways to lose weight, which is why there are approximately 5 billion new diet books written every year — that’s our unscientific, but probably not inaccurate, estimate. Speaking of unscientific, the problem with the plans in these books is their so-called “new” approaches to weight loss haven’t been tested, well, scientifically. And when they get scientists to pay attention, the plans often fail to produce the stellar results they claim.

One weight-loss method that’s gotten a lot of attention lately is fasting, where people go without eating for several hours (usually 16 or more) or even a full day. Search the internet and Reddit boards, and you’ll find passionate devotees talking about the advantages of fasting for weight loss, muscle gain and other benefits, like improved mental clarity. And while there is research to back up some of these claims, much of it is preliminary or was conducted on animals.

Lately, researchers have been looking into fasting more deeply and are starting to fill this knowledge void. A study published this May in the Journal of the American Medical Association: Internal Medicine sought to find out whether fasting was any better or worse at helping people lose weight than a more traditional diet. Here’s what they discovered:


The study looked at the effectiveness of two diets:

  1. One was alternate-day fasting, where subjects ate a very small number of calories (25% of their daily energy needs) on “fasting” days, and an excessive number of calories (125% of their daily need) on “feasting” days.
  2. The other program was more like what most of us imagine when we think of dieting: a calorie-restriction model where people aimed to eat slightly less than their energy need (75%) every day.


One hundred people total: 86 women and 14 men, aged 18–64 (the mean age was 44). They were obese, but did not have metabolic diseases (like Type 2 diabetes or metabolic syndrome). Their cholesterol counts and blood pressure all fell within the normal range. The subjects were divided into three groups — those who were put on an alternate-day fasting plan, those who were put on a calorie-restriction plan and those who received no intervention. Changes in their bodies were rigorously tracked with researchers using a digital scale (DEXA machine) and MRI scanner to record subjects’ weight and body fat throughout.



A full year. The first six months were a weight-loss phase, and the second six-months were a weight-maintenance phase.


Both the alternate-day fasting and caloric restriction groups lost about the same amount of weight — the fasters dropped and kept off 6% of their body weight on average, while the calorie-restrictors came in at a 5.3% loss. Those in the fasting group struggled with adherence, however. There were slightly more dropouts in the group (13 of 34 fasters quit, compared to 10 of 35 bowing out of the caloric-restriction group). The fasters often ate more than their target goal on fasting days, while consuming less than the allowed mark on feasting days.

The researchers also monitored the subjects’ cardiovascular health through markers, like their cholesterol counts. That’s where one curious result occurred, which researchers cannot explain: By the end of the second six-month interval, those in the fasting group had experienced an increase in their LDL cholesterol. (LDL is what we think of as the “bad” cholesterol.) The caloric restriction group did not.


  • If your goal is to lose weight, fasting is an option you can try. It appears to work about as well as daily caloric restriction. Alternate-day fasting, which this study examined, is one option. Other popular ones include a 12-hour daily fast, a 16-hour daily fast (often called the “Leangains” diet), a 20-hour daily fast (known by many as the “Warrior” diet), or a 24-hour fast once per week.
  • Keep in mind that, prior to this study, a lot of the most compelling research showing body composition benefits of fasting was performed on “hard gainer” young males (i.e. guys who have a hard time building muscle). The results may not translate so well to other populations.
  • One group of people who should be especially careful with fasting is women. The approach can cause a cascade of hormonal issues in women, including thyroid imbalances and menstrual cycle issues.
  • If you try a fasting diet, do so in consultation with your doctor, especially if you have any cardiovascular risk factors like high cholesterol or blood pressure. Monitor both of them closely. And, perhaps most important, pay attention to how you feel throughout. The body often sends signals when something is going right or wrong. It’s our job to tune in to them.
  • Remember that no diet approach is magical. What matters is what works for you.

About the Author

Cristina Goyanes
Cristina Goyanes

Cristina Goyanes is a NYC-based freelance editor and writer who covers topics including sports and fitness, health and lifestyle, and adventure travel for various national men’s and women’s magazines and websites. When she’s not feverishly typing stories at her desk, she’s exploring the world, from the Arctic to Antarctica and plenty of countries in between. Follow her adventures and more at


96 responses to “Science Investigates: Fasting vs. Calorie Restriction?”

  1. Avatar Susie Chapple says:

    Speaking for myself, I had a number of health issues, primarily high blood pressure. I ditched the breakfast and all the little snacks and only ate a lunch and dinner. Something incredible happened. I had energy that I hadn’t seen in years. Heartburn went away. I was sleeping better. I was much sharper at work. I was more pleasant to be around and as a bonus, I lost weight. My doctor was amazed at my progress that he had to ask what I was doing. I explained it and he’d not heard of it, which I found strange.

    This may not be the be-all, end-all in weight loss discovery, but the health benefits that I experienced are just too incredible to ignore.

    • Avatar Major Bummer says:

      It is interesting. I know a couple who do this, and have no trouble with their weight.

    • Avatar Kate Paullin says:

      Interesting. It definitely has to be person to person, because I lost weight and stayed full longer by eating 4–5 times per day, instead of the 2/day I was doing before.

    • Avatar henucu says:

      same with me.started doing 16-8 intermittent fasting since 2 month s and i have more focus and energy than before. i count calories and workout 5 times a week and still have energy to do more if i skip breakfast.

    • Avatar Tom Foogleflump says:

      I did that for many years, and maintained a light weight. Then I turned 55 and everything changed 🙁 No matter what/how I ate, everything stayed on me. I went up to 185 lbs., which on my small frame was quite a lot (I weighed 145-155 lbs. most of my adult life until age 55). Then on 1/1/2017, my wife and I decided we’d had enough and tried the Dolvett Quince 3-1-2-1 diet. What a change! By March 1st, I had dropped 25 lbs., and have stayed at 160 +/-2 lbs. since. Love the diet- it’s easy to follow, and you get 2 “cheat” days a week 🙂 I highly recommend it. I am moderately active, playing doubles tennis 3-5 times a week, and walking 2-3 times a week, so it’s not like I’m working my buns off in a gym.

    • One hundred people total: 86 women and 14 men, aged 18–64 (the mean age was 44). They were obese, but did not have metabolic diseases (like Type 2 diabetes or metabolic syndrome). Their cholesterol counts and blood pressure all fell within the normal range. The subjects were divided into three groups

  2. Avatar Steven Doyle says:

    I’ve been fasting for a few months with great results in weight loss and freedom from BP meds. The results of the study may have been drastically different if the fast was extended more than 24 hours.

  3. Avatar MelissaT says:

    I would love to see a study done comparing some longer fasts to calorie restriction. Alternate day fasting is cool and all but like mentioned in the article participants often did not keep their calories low enough on fasting days and also didn’t get them high enough on non-fasting days, which could have made a big impact on the results. I started with intermittent fasting, usually 18 hours. But after a few weeks I was able to start easily doing extended fasting and now like to do a 3-5 day water and black coffee fast every few weeks. It feels amazing and I love the results in weight lost and inches lost I’ve been seeing. I did however (on my doctors recomendation) start eating a ketogenic eating plan and became fat adapted for attempting fasting, fasting just came natural. Listening to the body is an amazing thing!

    • Avatar Karla says:

      I have to agree with you completely. I’ve been doing intermittent fasting for while now. I do usually 16 hours, but you really get so used to it that after a few weeks it’s so easy to go over the 16 hours. It’s amazing how I fee more active and how good I feel working out. You can mistakenly think the opposite but when fasting and eating right your energy level changes completely. I’ve never worked out so hard before. I do a low-carb/ high-fat diet with it. Which means a lot a veggies, good fat, and no sugar. I swear by it. For the first time ever I was able to actually stay on it, and it’s much easier to say no to junk food because I feel satisfied. I didn’t had to lose a lot, but I dropped a few lbs, but I lost 6 inches on my waist. That was just amazing! If your goal is to lose weight you should definitely try a intermittent fasting combined with a low-carb diet. It was life changing for me.

    • Avatar Ashley Wells says:

      i agree 100% about the keto diet, I tried fasting in the past on a typical grains diet and I went mental.
      Im now keto adapted and youre right, it feels perfectly natural.
      No more hormonal imbalances and mood swings like we get from a typical sugar filled grains diet.

      Ive lost 30 pounds in the last 11 weeks on this ketop adapted fasting diet
      (I do 18:6 OMAD)

      Ill never go back to that woe

  4. Avatar MrTomalu . says:

    I just started intermittent fasting 16/8 and I’ve lost 9lbs. in 2 wks.

    • Avatar Patricia Johnson says:

      What is a 16/8 fast?

      • Avatar somecallmemike says:

        You eat your normal caloric intake for the day in a 8 hour window of time (I do noon – 8pm) and then you eat nothing but water or maybe one zero cal drink for the remaining 16 hours (8pm to the next day at noon for me). This gives your body a chance to eat through the calories you ingested, and then for a period of that time it starts converting the visceral fat in your body into the energy molecules your cells need to run. So you lose weight by burning through your fat stores at the tail end of your fasting period. There are a number of fasting methods that you can research, just google intermittent fasting schedules and you will find one that fits your lifestyle.

  5. Avatar Jane says:

    I think the main point to weight loss and maintenance is in their last sentence. “Remember that no diet approach is magical. What matters is what works for you.” Our bodies are so different that there truly is no “one size fits all”, as I expect most of us know. Even for people who are very similar, there can be very many differences, some of them significant. I’m all for research and trying different things for myself to see what works for ME and even sharing it with others. I learn a lot listening and reading different approaches.

  6. Avatar Sweets says:

    I don’t know that a 12 hour fast is any different than a normal day. If you eat dinner at 6pm and don’t have breakfast until 6am, that’s 12 hours. where is the benefit?

    • Avatar Nicola Kerr says:

      If you fast it had to be for longer than 12 hours. I try to do 36 hours twice a week. Or you can do 24 hours. You are right, 12 hours is just a usual overnight fast while you sleep but this article is talking about a longer amount of time than that.

    • Avatar Frank L Young says:

      Most Americans snack right up until they go to bed (usually too late) meaning that they only get a 6-7 hour respite from energy in. I personally do four day five night water fasts every couple of months which are even better for other reasons but am a big proponent of 12 hour daily overnight fasts for everybody. Not only does it give your body ample time to do it’s housekeeping but also eliminates consumption of what is generally junky food between the evening meal and bedtime.

      • Avatar Lilarose Davis says:

        I am a diabetic, and there is NO WAY I can go overnight for 12 hours without my blood glucose going well below the lower numbers that are safe. You could fall asleep and never wake up. Half an hour before bed I have half a wheat bread with a little bit of peanut butter. My pharmacist does this himself.

        • Avatar Frank L Young says:

          Well, most Americans are not diabetic … yet. Having said that, there has been a lot of research in the past few years that suggests that various forms of fasting could cure or at least ameliorate your condition if it is T2. The real problem seems to be more of a conflict with insulin use and, perhaps other oral diabetes medication more than with the diabetes itself. In any event, all of the “experts” say that diabetics—especially those on medication—should not pursue any kind of serious fasting without medical supervision. Sounds like sound advice to me but I would strongly suggest that you consider fasting and/or a LCHF diet as a treatment for your condition with close medical supervision.

        • Avatar Relica says:

          You cannot safely fast without medical supervision while on most diabetic medications or you risk dangerous hypoglycemic episodes, which can be terrifying and deadly. That said, Google Dr. Sarah Hallberg and watch her video on Reversing Diabetes which is informative. Hope you do so!

        • Avatar Lauren says:

          Dr. Jason Fung actually treats type 2 diabetics using an intermittent fasting low carb high fat diet. It’s certainly possible to fast with diabeties just not recommended without a doctors supervision. Google him if interested he has a ton of podcasts out there.

          • Avatar Gail says:

            his books are certainly interesting… I have a friend who has switched to his way and lost a lot of weight feeling great…

          • Avatar Ashley Wells says:

            thats the guy in toronto right?? I mean meaning to read his book or even meet him irl as I live there too

        • Avatar Don Purvis says:

          I am a type 2 diabetic. It has worked wonders for me. But I am not on insulin. I control with pills and diet. Doing this has cut my pills almost in half in a month. I am now off Jardience and Glipizide is at half.

        • Avatar Ashley Wells says:

          you should not consider fasting on a typical grains diet, but I encourage you to research ketosis diets in conjunction with fasting,.
          (and talk to your doctor before doing anyyything)

          diabetes runs in my family I am literally on this diet to prevent getting diabetes and many many diabetics use this diet to ELIMINATE their diabetes.

          dont take my word for it, please esearch online

          ketosis diabetes and fasting and speak to your doctor as well.

          good luck

  7. Avatar Dan says:

    I have had success fasting for 14 weeks between Sunday evening meal and Tuesday lunch. It’s about 44 hours restricted to my morning coffee with whole milk creamer and a 300 cal snack Monday afternoon. Other days are essentially 16-18 fasts as I have left my multi-decade morning cereal habit behind and generally skip breakfast. The other 12 meals of the week, I eat what I want, except I’ll try to go low carb if an option. At 55, I’m pleased I’m back to my 20s weight in the upper 180s (down about 30), been back to the gym to tone, feeling great!

    • Avatar uma srilakshmi says:

      can you share the plan that u followed?

      • Avatar Dan says:

        I pretty much did. After reading several sources on fasting and the Keto diet, I made up the plan that best fits my lifestyle. Between Sunday evening and Tuesday lunch, I have about 400cal from two mornings (M&T) of whole milk creamer in my coffee and my Monday afternoon snack. My typical snack is about 60-65 pistachios (<250cal) because by the time I crack them one at a time and eat them, it gets the "fed" signal to my brain. Tues-Sat, I skip breakfast unless it's a pretty pure protein like scrambled eggs or a ham and cheese omelet. This gives me a 16-18hr fast for the other five days of the week. By combining these two fasting techniques, I believe I am better able to stay in a fat burning mode of ketosis.

        What I have learned in the process is that I broke the carb craving first. I used to be a person that had to have a little sweet after every meal, even if it was only 2-3 squares of chocolate. I don't have that habit anymore and I don't miss sweets. Secondly, I learned to break the meal craving. Sure, I'll get a couple of hunger pangs on Monday, but they go away in 10 min or so. The other days, I've realized that the 3-meals-per-day mantra may be a cultural habit, but not entirely necessary. Rhetorically, if I have just slept 8 hrs, why do I need fuel? Breakfast has been the easiest skip of all.

        I don't count calories, but I don't try to overdo it when I do eat. I'll find low carb substitutes when I can, like garlic mashed cauliflower (yum!) instead of potatoes. I don't deny myself sweets or alcohol, but I don't need a constant supply. Everything in moderation! Have REAL butter, REAL sugar: just eat REAL food in general.

        I don't know to whom to attribute it to, but I like a comment I read from a doctor or nutritionist recently that said something like, "one-third of what you eat keeps you alive, and the other two-thirds slowly kills you."

        Life is short! Don't deny yourself, just have everything you want in moderation. Love life, your neighbor, and love the Lord!

  8. Avatar robinbishop34 says:

    Intermittent fasting is simply a way to control calorie intake, there is no special fat burning benefit from the fast itself.

    In other words, a person disciplines themselves to restrict calories during part of the day when it is easier to do, so they can consume their allowable calories during a time of day when eating is more desirable. Its a method to make calorie restriction easier.

    • Avatar Mark Magda says:

      Not true. It alters Growth hormone and insulin to favor a fat burning environment.

      • Avatar robinbishop34 says:

        Ha…I knew this was coming. Even if growth hormone were increased a 1000% it wouldn’t allow one to lose weight in a surplus.

        • Avatar Mark Magda says:

          I think it would a little as well as help reduce losing muscle but more important is lowering insulin.

          • Avatar robinbishop34 says:

            Calorie restriction with proper macro breakdown. Thats all there is to it.

  9. Avatar Valarie Franklin says:

    Wow! It appears that the author went in on this article with the intent to debunk fasting as method of weight loss. Problem here is that yes fasting works as a weightloss method but most people that use this method correctly are aiming for preventative medicine means. Weightloss is merely a side-effect. Both plans focus on calories restriction, however fasting lengthens the time that your body is in a restorative state. With mere calorie restriction this process is interrupted many times throughout the day and never has a chance to really begin. I have many more thoughts on this article but I am going to leave it here.

  10. Avatar Krissalee85 says:

    Maybe the LDL levels were raised in the fasting group because they ate more indulgent, unhealthy foods on their non-fasting days. When you feel like you’re starving, junk food is even harder to resist.

    • Avatar jons says:

      That’s not how rising LDL levels work. It is more likely a liver function issue which leads me to believe that fasting is a bad thing. I’ve recently lost 40 pounds and have done so by eliminating alcohol, portion control and exercise. I am never hungry and feel fantastic.

  11. Avatar Danny22 says:

    I’d like to say that the fasting is a good idea, in some conditions. For a person that is on meds, be careful. I was.
    I did some fasting a few years ago, which helped me a little bit. I’ve got Epilepsy, so I had to be careful.
    The fasting I did wasn’t just meals. It also was keeping to myself, no video games, no movies, no long time watching tv with my son (who doesn’t have my disease). Through about the 16 hour time plan (I would guess that’s about how long I went without food, movies, & video games).
    I’m also a Christian. So I spent time meditating. Not crazily; on my knees putting my head down to the floor, making weird noises. WEIRD!!
    Anyway, I was building my relationship with the LORD. Back then, it got much stronger. I don’t have hard seizures; there’s only a range of 4-8 a month, & last a few minutes.
    A few have gone away & now I can feel an aura that one is gonna happen sometime soon. GOD opened up my mind to a few things I didn’t see before.

    My point on here is…I lost weight from the fasting, my awareness opened up & relationship with GOD got stronger.

  12. Avatar LSmith33 says:

    I don’t think I would do an every other day fasting. That really doesn’t seem too healthy. I followed a program (by Richard Simmons) where normal calorie intake to lose weight was 1,200 calories/day (just an example) and during the first week of the month it was reduced to 1,000 calories/day. He called it the “Blast Off Week.” I found that it helped jump start the month’s weight loss and added just enough variety to keep me from plateauing. I was consistently losing 1-2 pounds a week following that diet. I also walked 30 minutes a day (well, I followed Leslie Sansone’s walk away the pounds program). I lost 42 pounds in about six months.

  13. Avatar Michelle says:

    LET’S NOT FORGET WITH ADF YOU ONLY NEED MY FITNESS PAL LOGGING EVERY OTHER DAY! Follow the money. As an ADFer with great results, I see so many holes in this study. First being on ADF you usually “fast” or reduce to 500 calories for a 36 hour period, not 24. There are many more.

  14. Avatar Keren Solomon says:

    I would love to see a food log of the calorie-restricted group versus the fasting group. The LDL levels being elevated could be explained by the types of food – perhaps those that fasted on one day over-compensated the next with two Happy Meals – you can easily have asked to keep a food log to compare what TYPE of calories they consumed. 500 calories of veggies are not metabolized in the same way a 500 calorie cheeseburger is metabolized.

  15. Avatar Lilarose Davis says:

    I have had great success using the MyFitnessPal food diary and entering my daily calories on that program. My doctor says 1,000 cal a day while doing this diet but the diary won’t let me enter a number less than 1200. I lost an easy 18 lb in 2016 and plan to lose another ten. Twice in my life, once in the 1970’s, I have lost weight by counting calories The MyFitnessPal food diary makes it so easy.

  16. Avatar Oldspeare Silverback says:

    I am on my third week of 16/8 and I like it very much. I use Fitness Pal to count calories and have eliminated most bread and sugar. I haven’t lost much of the 40 I have to lose, but I am 58 now and weight comes off much slower than it used to. I have been briskly walking 3-5 miles a day and weight training at the gym 5 days a week and quickly gaining strength, so I may be trading fat for muscle at this point since I look and feel better.

    For some reason I am able to embrace the hunger better on this system. I always felt that breakfast fired up my hunger and after a healthy sack lunch I was so ravenous after work that I plowed through hundreds of snack calories and double helping meals. Now I easily deal with the hunger and eat a huge healthy lunch of 3 cups of greens, 200-300 gm of chicken breast or fish, nuts, veggies, and an apple. I eat an evening meal with my family, but my appetite is manageable because of the huge lunch. No more seconds and thirds.

    I appreciate the article, even if it seems to caution me against fasting. I might have been talked out of 16/8 by this article if the method hadn’t been working so well for me. And I appreciate the support I have read here from other fasters. For me, constantly underfeeding my body–as I had done on other diets–put me into yo-yo mode and failure. Fasting for 16, eating healthy and big during the eight hour window, and keeping sugar, bread and potatoes out of my diet has been allowing me to stay at 75% of my maintenance calories really easily. I will be stunned if my LDL hasn’t dropped 50 points six months from now. Maybe I am only losing a pound a week–blame that on being old and adding muscle from exercise. But a pound a week makes a difference after a year.

    • Avatar Angela J. Ballard-Landers says:

      I started 16/8 last night so today’s my first official day. I started with 2mile power walk around 6:30am and actually fasted 17hrs, not by choice. I had to run out to pick up lunch.Tomorrow’s weight day. I was able to manage the hunger pains by drinking iced black coffee, decaf Passion Fruit Tea and water. It really didn’t become too noticeable until around the 16th hr. So far so good!

      • Avatar Ashley Wells says:

        how are you doing with it now?
        You should try this in conjunction with a ketogenic mealplan,
        I have tried fasting in the past on a traditional grains diet and felt terrible.

        I never get hungry fasting on a keto diet and lost 30 pounds in the last 11 weeks

    • Avatar garland vincent says:

      16/8 is working good for me,too,been on for 3 weeks, down 9 pounds,more important my 34 pants are loose again,so i suspect lots of fat lost,,, my mind has cleared,, my work out has stayed the same and my hunger has been reduced , i lost a lot of weight on the six meal a day plan, but i gained some weight back and struggling with hunger and insulin resistance, 16/8 was just what the doctor ordered ,

  17. Avatar Sqandaraneh says:

    Here, let’s start a study where we defined Fasting as NOT Fasting and examine the results! What the heck! ? 25% fasting is NOT fasting but a stronger calorie restriction!

  18. Avatar Amy says:

    The macronutrient breakdown for those fasting is the most important apect. If you look at the ketogenic diet it is a very low carb/high fat diet that turns your body into running off ketones making you less hungry. Fat adapted people don’t need to eat as often as those that rely on glucose for energy. That study needs to dive deeper into macronutrient breakdowns- the results would change dramatically.

    • Avatar davedave12 says:

      follow your religion

    • Avatar robinbishop34 says:

      Calorie limits, with proper macro breakdown is the ONLY important aspect. If one needs to “fast” for a length of time to more easily manage this, then so be it… but fasting has nothing to do with losing fat any more effectively.

      • Avatar Ashley Wells says:

        youre incorrect, a person on a keto diet uses body fat for energy, i you dont supply the body with energy it takes it from the fat.. especially fasted HIIT has been proven to hasten the time one needs to lose body fat..

        dont spew ion about things you clearly havent researched.

        • Avatar robinbishop34 says:

          Fasted HIIT is probably the best way for the body to utilize amino acids that synthesize into muscle tissue… particularly if you’re carrying little excess weight.

          You shouldn’t even need to do any cardio whatsoever if you eat in a deficit. Cardio is just a way to burn a surplus. You’d be much better off and obtain a much better overall composition with heavy weight, push/pull, compound movements and proper macro breakdown.

          I know what I’m talking about.. take my word for it.

    • Avatar Gregory Robinson says:

      I resemble that remark! You are absolutely correct in a Sassoon kind of way. Yeah!

    • Avatar Ashley Wells says:

      soo true. I used to do OMAD on a ‘normal’ diet of grains and sugar and felt miserable,
      Now I am fully keto adapted and my OMAD is really all my body asks me for. I am high energy and good mood all day, like never before on the sugar roller coaster.

  19. Avatar Steven Wilson says:

    Some of these studies just feel insulting.

    I’m not sure what the scientists were trying to prove, or even, if a vendor sponsored the study, what the vendor was trying to prove. I don’t know these other diets. I automatically assume (and I understand the risk) that anyone using fasting is most likely using ketosis. Anyone using ketosis is likely educated enough to see this study proves nothing about anything they care about….but likely, this hits headlines as “Fasting does NOT work!”. Again, anyone doing ketosis doesn’t care. Anyone doing keto knows fasting is useless if you’re not keto adapted. …but maybe the scientists got confused? Did they not research why we would fast? We fast to get into keto faster. Eating carbs after fasting wastes the fast.

    Fasting may not have much research but intermittent fasting has LOTS of research when associated with ketosis. Intermittent fasting with keto has been used to control a number of disorders that resisted other treatments since the late 1800’s. The use of ketosis is well studied and well documented in those uses.

    Maybe there’s a whole bunch of people out there using fad diets derived from people who skimmed ketosis books. If that’s the case maybe this study will help them avoid the certain failure. But for those folks, maybe we could put in a reference to uses of fasting where it does work so these folks who are desperate to lose weight can find a solution that actually works?

  20. Avatar Relica says:

    It’s interesting that the study does not disclose what exactly participants ate, which seems key in determining outcomes. I suspect it was carb loaded since so many dropped out and couldn’t sustain fasting, a predictable outcome if you’re burning sugar for energy. Fat burners in ketosis can easily fast because they no longer crave sugar. Also, LDL increases during fasting is not uncommon because often it’s just the liver compensating with a sugar dump particularly if you’re a fat burner.

  21. Avatar Yes_General says:

    Calorie restrictions is definitely effective for those of us that are weekend warriors and do most of our heavy workouts on weekends. I lost most of my weight by eating practical nothing fulfilling on weekends and walking/jogging for 2hrs on Saturday/Sunday. However the real key that I noticed is now that I’m getting older watching my liquid intake plays a bigger role. Yes we’re supposed to injest a certain amount of water per day but what they don’t tell you is that liquids don’t just go away if you don’t burn it off. So I literally have to stop drinking liquids after 6PM other wise my body won’t be able to burn it off. Thus creating water weight. Meaning alcohol consumption also has to be cut out occasionally because obviously it makes you thirsty meaning more liquids.

    Severe calorie restrictions on weekends. Increased cardio to 2hrs per day. Watchful eye on consumed liquids and buying a scale helped me lose 30lbs. I have about another 20lbs to go.

    FYI: my diet took a back seat last week. I had a Philly cheesesteak, shrimp/chicken low mein, hamburger with Fries over a 3 day period and gained 3lbs. My will power is restored again and back to the routine haha

  22. Avatar tommy5677 says:

    Better option: intermittent fasting where you only eat between the hours of 12 noon to 8 pm daily.

  23. Avatar OleDad48 says:

    “Increased LDL” is not enough information. We need to know the size of the LDL — small and dense LDL or large and “fluffy” LDL. Dense LDL is dangerous. Fluffy LDL is harmless, and from what I have read, intermittent fasting (IF) produces the fluffy type of LDL. It also increases HDL (a good thing), which means it also increases Total Cholesterol (LDL+HDL). Most doctors look at increased cholesterol as “bad,” but this is slowly beginning to change. Dr. William Davis, a cardiologist and author of Wheat Belly and Undoctored, declares “total cholesterol” numbers are meaningless. So look at HDL (if it increases over time, this is good) and low density LDL (if it increases it doesn’t matter).

    There are other values gained from IF. Dr. Jason Fung (nephrologist and author of Obesity Code) declares that fasting (0 calorie intake) for 16- to 24-hours resets the weight set point lower (allowing the body to lose weight naturally), and decreases insulin resistance (the cause of many metabolic diseases). Calorie restriction does neither of these.

  24. Avatar Kyle Coates says:

    So absolutely no information on what they were eating?

  25. Avatar Amy says:

    I like the 16:8 Intermittent Fasting. I find it to be the easiest to adhere to. (for me anyway)

  26. Avatar Bob Jones says:

    EVERY SINGLE ONE OF YOUR ARTICLES IS “CLICK BAIT!” Total JUNK!! I stopped reading them a LONG time ago. This one did have me curious as to the “author’s” particular (incredible uniformed) take on a 600 word “read on the crapper” piece of… well, same thing that goes in the crapper! I HATE that Under Performer (and their CRAPPY- notice a theme here?) line of products bought MyFitnessPal. App is so-so, corresponding blog is… you guessed it, SHAT!!! THIS IS THE LAST TIME YOU SUCKER ME!!!

  27. Avatar Lynn Baum says:

    I think I might of bee part of this study. I did what was called the one day diet. It was the Alternate-day fasting. Here is my take on the whole thing. T I was chatting on the board “sparkpeople” and found someone doing it at the same time I was. We both did it for 4 months. On one day you ate these food tabs and the next day you were to eat what ever you wanted. I will refer to sparks friend as person 2. Person 2 worked out 3 times a week with a trainer. I think I was doing jazzersice. The biggest thing I noticed is that there were many people that dropped out and started calling things a scam and anything else they could think of. So I ate the waffes during the day and might of had something like a pc. of fruit or some carrots. For dinner I would have a salad with pickles for dressing on the diet days. On what they called food days I did watch what I ate but what I noticed is that I really craved nutrition. I am talking lean meats, veggies, fruits. Things like bread or ice cream didn’t have enough nutrition to last me over the diet day. Over the 4 months I lost 20 pounds. Same for person 2. The biggest thing that kept us going was the support of each other. Because we both started on the same day and we both had about the same to lose we had many of the same effects from the diet. So my take away is that the support of fellow healthy eaters is more important than the diet it’s self,

  28. Avatar Valarie Franklin says:

    Okay I do have more I must say….

    First of all, you say “Lately, researchers have been looking into fasting”…really? Fasting goes back to Jesus, Hippocrates, and even Albert Einstein who all understood the importance and benefits of fasting.

    Second of all, you mention the Leangains and Warrior method of fasting (which are by far the most popular means of intermittent fasting) but you failed to use these methods in you control group comparison. Why? Even OMAD (One Meal a Day) would have been a better choice over “Fast one day and eat whatever your heart desires the next day” regime that you used in the study.

    Third of all, your bio-metric screening results are wack! You failed to mention WHAT the groups were eating. Do you not think that is relevant???? They were probably eating a bunch of junk on their non-fasting days to make up for what they missed the day before. Now to be fair, speaking as a vegan Warrior/mostly OMAD faster, it is true that we sometimes have LDL issues and that is because we typically strive to eliminate oils from our diet opting for natural oils found in fruits, vegetables, and nuts. Elimination of oils in a diet is not necessarily a good thing because our arteries need to be kept running like smooth oiled pipes. However, it is possible to get enough “good” oils from a whole foods way of eating if you eat with intent and recognize your bodies needs.
    My bio-metric screening results from just today prove that:
    Total cholesterol: 142
    HDL cholesterol: 63
    LDL cholesterol: 79

    Lastly, most doctors will not recommend fasting. They typically lack nutritional training, have limited time to consult you because of time limits imposed by insurance companies, and are more apt to prescribe medicine than recommend something that is preventative. There are some good doctors out there that have gone above and beyond their initial training who will recommend measures to prevent illnesses. Find them.

    • Avatar Susie Chapple says:

      Your post, Valarie, is exactly on point. I couldn’t have said it better myself.

    • Avatar Anna Scott says:

      Also…the article doesn’t mention or differentiate between LDL particle sizes. As well as small dense LDL particles, seen to be more harmful, there may also be light and fluffy LDL particles, which are not perceived as harmful. Instead the article groups them all together, giving the misleading impression that there as been a total rise in ‘bad’ cholesterol.

    • Avatar Ashley Wells says:

      girl you reallly know youre science. I would love to chat with you im not creeping im a girl, im doing OMAD currently my diet is keto though so super high fat a lot of meat etc.
      as a former vegan and someone worried about gout etc Im not sure i will continue this woe for ever would love to discuss more with you about your woe if youre willing/able

  29. Avatar GarriottSK says:

    I started dieting in 1968 when I was 14 years old. I have counted calories on various diets. I’ve counted carbs on the Marine’s Diet when I was 18, then later on the Atkin’s diet and recently on the New Atkins diet. I have counted points on the Weight Watcher’s Diet a couple of times. Plus there have been many fad diets I have tried. I have always lost some weight only to gain it all back and then some. I discovered intermittent fasting last summer and started doing it every day on August 1st, 2016. I fast 19 -22 hours every day and have a 2 to 5 hour daily eating window. I’ve lost 41 lbs so far and 7 inches in my waist. There are no words to express how happy and thankful I am now. I no longer count anything. I’m 62 yrs. old but feel like I’m 30. I take no medication, sleep like a baby and have so much energy that sometimes I don’t know what to do with myself. I will live this lifestyle always!

    • Avatar Gail says:

      That is so encouraging – I’ve been messing around with WW point counting and intermittent fasting and haven’t committed really to either……You have done amazing!!! I want to do the fasting but am terrible still with bread and sugar craving…can’t seem to do either system long enough to get past that.

  30. Avatar Laura says:

    The take away point is that this one study with a very small sample size. Another take away point is that one should rarely use the results from one behavioral study to inform their behaviors.

  31. Avatar Chewbacca2000 says:

    Is there any way to get that unit measure in, let’s say bushels? Also, how many hands tall are you? Cubits would suffice too if you don’t know hands. Btw, you’re 80 and doing that? All kidding aside, I am nothing short of blown away and have to tip my hat to you Sir. Honestly, it’s darn inspiring. Thank you for sharing that.

    • Avatar Tricia says:

      A stone is precisely 14 pounds.

    • Avatar Gabrielle says:

      Americans seem to measure in pounds, which British don’t understand when applied to weight. Most British people over 50 measure in Stones and pounds, under that age in Kilos, like the rest of Europe. You mock because of a lack of knowledge.

    • Avatar Chewbacca2000 says:

      Yes, was being a smart alec. Apparently not a very funny smart alec. I do tip my hat to you for your progress through and appreciate your sharing the information of your success and find it impressive.

  32. Avatar Sandra Parsons says:

    Interested in reading your post I am a lady in my very early 70’s and have just started the 5:2 diet, it ‘s principles really suit me, my fasting days ( I do eat) are Mondays and Thursdays. I intend to increase my exercise as I go along. Your story is very inspiring. Thanks for sharing.

    • Avatar Ashley Wells says:

      best of luck sandra.
      Have you considered quitting sugar as well? This was so hard for me for 2 weeks, Im a lifelong carb and sugar addict but i did it. I found alternatives and my tastebuds changed.

      ive lost 30lbs in 11 weeks since i quit sugar and my risk of diabetes has gone from high to nil

      • Avatar Sandra Parsons says:

        Hi Ashley. Luckily I am not a sweet tooth. I do not have sugar in tea or coffee and have chosen sugar free yoghurt. a diet soft drink now and again. Cut out my nightly white wine and reduced my carbs. First week have lost 1.6kg on 5;2 which has almost been 16/8 on my fast days as I don’t feel like breakfast now which is good as I had toast every day!.

  33. Avatar Craig McWhirter says:

    I like a lot of the comments (well informed) and I think that they show that we are all different and try different things depending on short medium and long terms goals, what our fitness is like and where we are in any cycle.
    I have tried the Brad Pilon, ‘Eat Stop Eat’ and it really works well for me.Basically it recommends a fasting period of 16-24 hours, once or twice a week but you do eat every day and do not (necessarily) count calories. What works for me is stopping at lunch time one day and starting eating at lunch the next.

  34. Avatar Mary says:

    I’ve just read the biginning and stopped! Fasting is not restriction of the number of calories, in fact I eat more calories than before since I began fasting, on 2 big meals per day and on a good nutritive collation. The fact of “not to eat during a lap of 16 hours” permits to my body to eliminate toxines, and feel so better !!!! And that’s a way of life, not diet for weight loss, even if it gives me a top body 🙂

    • Avatar Mickey M. says:

      You may or may not feel better with fasting, but that has nothing to do with “toxin removal”. Your liver and kidneys do a pretty good job at that regardless of what you do. Not like if you eat every 3 hours the toxins remain in your body and if you fast, they don’t… If that were the case, you’d be dead long time ago… go read a book, not just article titles on Facebook…

      • Avatar Megan Watts says:

        I agree with the sentiment of what you’re saying, and I often feel this way about people who source their information from Facebook, but it’s not necessary to be rude or insulting.

        • Avatar Mickey M. says:

          I was neither rude nor insulting. Spreading misinformation on the Internet because someone read a Facebook post backed by research done at Bullshit University about how fasting removes toxins is much worse than me recommending them to go read a book.

          And if you thought that’s rude, what would you think if I were to tell you to get your head out of your ass and stop derailing the subject with your political correctness preaching as it has nothing to do with fasting or nutrition? Mind you, I would never tell you that…

  35. Avatar James says:

    I think this is slightly unfair. Most fasting diets actually recommend not overeating on non fasting days and having tried them you tend not to want to overeat to”catch up” as you might expect you will. Most popular 5 and 2 diet you eat about 25 per cent of your calories twice a week and just 100 per cent other days. If this was tested i think you wpuld see an even bigger difference although here you can clearly see that fasting still works.

  36. Avatar kayfab says:

    Fasting is the best thing for me, after 3 days you don’t feel the sugar urge, and i lost tones of weight, i train 6 times per week but fasting really help kick things in i am also 45. Lost close to 35 pounds in 6 months.

  37. Avatar jamie oliver says:

    Fasting isn’t a diet. What nonsense.

  38. Avatar Ashley Wells says:

    good job david, and thank you for sharing what works for you!

  39. Avatar Dredre416 says:

    I was about to say what an utter and complete waste of 4 minutes of my life, then I thought how can I complain when a group of primitive researchers and 100 applicants wasted a year of theirs. Here’s the truth, I’ve been on the warriors diet for quiet some time. My first 3 weeks I lost 4 percent body fat. My cognitive function along with my core strength has drastically improved. This diet not only benefits your body BUT also displines you. It changed my life for the better. This alternate day garbage is BS then probably why the stats were at par. You want to fast that’s a 24/7/313. That’s if you want to mess around one day of the week. I don’t and won’t until I reach my desired goal.

  40. Avatar Steve Silva says: My name is Steve Silva, I have been in the industry for over 37 years. I started as a patient weighing over 430 pounds. Over the past 37 years I have seen that people who cut fat, increase Complex carbs, watch simple starches especially the ones that call their name. In other words Don’t buy and stock the house with foods that call their name that they can not afford calorically to maintain their goal weights find it easier not only to lose weight but maintain the weight they loose. They also maintain or begin a weight training program to regenerate muscle and maintain same. They are more likely to loose the weight and maintain that loss. The one addition is Coaching. If people have tried to loose weight and fail at loosing or keeping it off. They need a coach to help them set realistic goals and be accountable to.

  41. Avatar Codger says:

    As expected, the Fasting Zealots won’t stand any article that doesn’t show their chosen diet is some kind of magical miracle for fat loss.

    Study after study shows that all diets are pretty much equal when it comes to fat-loss….once you’ve accounted for calories in vs calories burned. All the hyperbole about post-absorption phase, insulin cycles etc are generally red-herrings. IF has not been shown to confer meaningful advantages in losing fat over and above it’s implied calorie restriction.

    Come at me IF Zealots! Show me the evidence it causes more fatloss than mere calories restriction…

  42. Avatar Codger says:

    Well you might want to argue that with Michael Mosley who is a big proponent of the low calorie “fasting”.

    But that aside, many trials, even the ones quoted by IF advocate Dr Jason Fung, constantly show that IF is NOT superior to simple calorie restriction in terms of fat loss. The study Fung quotes concludes:

    “This study is the first randomized trial comparing ADF with moderate
    daily CR. Results suggest zero‐calorie ADF is safe and tolerable, and is
    equivalent to moderate CR in producing short‐term weight loss and
    improving body composition and metabolic parameters. While relative (%)
    weight loss was greater in the ADF group at the end of the 8‐week
    intervention, this difference was only marginally significant (P = 0.056) and may be driven by the differences in baseline body weight between groups.

    What it did show however was a significant difference is where the fat was lost – more off the abdomen with IF, which is an interesting finding.

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