Why Alternate Day Dieting is Disastrous

By Nicole German (RD, LD)

Try eating over 2000 calories one day, and then depriving yourself to 1000 calories the next day. This is another form of yo-yo dieting.

Some are saying that alternate day dieting will help to keep you satisfied, but ultimately result in a calorie deficit and weight loss.

After all, Dr. Oz uses this technique for himself, so it must be effective, right?

Don’t Mess with Metabolism

  1. The big problem here is that you are playing with the metabolism. You would put your body in starvation mode one day, and then at a more normal calorie diet the next day. This could set you up for overeating and defeat the purpose of the diet plan.

    Plus, studies have shown that long term yo-yo dieting over the years can slow the metabolism.

  2. The creators of this diet thought that by never staying consistently low with the calories, one would be able to avoid the “starvation mode” metabolic slow-down. You would be able to eat low calorie one day, and then the next day, rev the metabolism.

    This is a great idea, but the metabolism is not that sensitive. It takes years of following a specific calorie level to change the metabolism.

Instead, Find Your Perfect Calorie Level

If your goal is weight loss, finding the perfect calorie level is the key.

It is tricky, but if you create a calorie deficit that is not too low, you can trick the brain into thinking you are not dieting. You will not get as hungry, will still stay satisfied, and keep the metabolism revved.

This type of calorie level usually results in .5 to 2 pounds of weight loss per week.

The One Positive

Following the alternate day diet can actually keep you satisfied with your food intake. Knowing that you can have a normal calorie level some days and only have to deprive yourself a few days is a relief for many.

However, the positive does not outweigh the negatives.

Have you ever tried this high calorie, low calorie diet?


  1. Tom Davis

    Alternate day fasting was a disaster for me. I lost 34 pounds, my pre-diabetes went away, and my blood presssure dropped by 15 points. On top of that bad news, my triglycerides fell by 50% and my HDL almost doubled. My cardiologist, who is absolutely gorgeous, told me that my health has improved so much that I only have to see her once a year now instead of every 90 days. Life sucks.

  2. Justina

    You’ve inspired me. I was under the impression that to be a columnist, one would need to possess a valid, well researched opinion. I’ve also been given the illusion that well cited facts were important. How silly of me since your article actually lacks general fact. Had you actually put your college training to good use you would have been aware that your body will not go into “starvation mode” in a 24/48 hour period. A monkey could produce a greater article.

    • Richard

      Justina, I appreciate your opinion varies to that of the person writing the article about metabolism. However, is there really any need for you to reply in such a sarcastic and obnoxious manner. I happen to agree with what you are saying. I just wish people didn’t feel the need to be so insulting and rude. Your reply would have far more credibility and positive response if you didn’t sound like a teenager having a tantrum just because somebody has a different opinion to you. That kind of attitude is never going to achieve a positive outcome.

  3. seb

    I am a personal trainer and work out with my clients about 2-3 times a day.
    I also do my own yoga practise and lead an active life.
    I have done the alternate day fasting for over 2 years and have had really great results.
    Your body will adapt and it does adapt to different ways of living. The amount of food most people eat is ridiculous. Most people will consume enough calories for their entire day in just one meal.
    Not saying it is right for everyone, but with proper knowledge and sensibility it can heal the body.
    If you are wondering how I got to the ‘most’ people overeating idea, more than 50% of people in UK and USA are apparently overweight, and that weight doesn’t come from fresh air and water alone.

    • seb

      I meant to add. yo-yo dieting is normally classed as someone who cannot stick to one diet but tries many to achieve results. A lot of people make this mistake when the same diet calls for different methods of eating. Otherwise, if one day you eat a different meal to the the next you would also class this as yo-yo dieting as you are not sticking to the same meals each day.

  4. Mickos

    May I recommend the author of this post read Eat, Stop, Eat.
    A very informative book regarding how our human bodies work with regards to being in a ‘Fed’ state or a ‘Fasted’ state. This book does not try to sell you anything and just explains (with references) how our bodies react to feeding and fasting. After all, we are designed to forage and feast when food is available and store fat so we can fuel ourselves for our next meal. We spend on average 20 hours a day in a ‘Fed’ state. When did you lasy willingley give your digestive system a rest.?
    Intermittent fasting will not put your body into starvation mode. This statement is unfounded and a ridiculous thing to tell people.
    This is straight from the food industy’s mouth. They want you to east 7 days a week, 6 meals a day (and the rest)
    Give your tummies a break. You’ll fell so much better. It’s not just for weight loss

  5. Dr. Richard Harrison

    I must take issue with some of the statements you have made which are just plain wrong. You say “It takes years of following a specific calorie level to change the metabolism” which is profoundly mistaken. See http://www.ncbi.nlm.nih.gov/books/NBK22414/ (Biochemistry. 5th edition.
    Berg JM, Tymoczko JL, Stryer L. New York: W H Freeman; 2002) which explains clearly how food intake, and specifically food intake followed by starvation, alters the metabolism very quickly indeed, and it is a straightforward matter to change one’s overall MR in fairly short shrift.
    In short, the metabolism is extremely sensitive (ask any diabetic) in direct contradiction to your statement.
    Your overall observations on alternate day fasting fly in the face of current research. A large body of evidence for the physiologic benefits and life-extending properties of calorie restritcion now exists. Restricting daily energy intake by 15–40% has been shown in both animals and humans to improve glucose tolerance and insulin action, which indicates an enhancement in insulin sensitivity; to reduce blood pressure and the heart rate, which is consistent with benefits for cardiovascular health; and to reduce oxidative damage to lipids, protein, and DNA, which implies a protective effect against oxidative stress. Many other effects of CR have been documented, including increased average and maximal life span, reduced incidence of spontaneous and induced cancers, resistance of neurons to degeneration, lower rates of kidney disease, and prolongation of reproductive function. See http://www.ajcn.org/content/86/1/7.full for a very good summary of current research.
    You may call that ‘disastrous’ if you like, but you do not state you reasons or the basis for such a comment.
    This is not a ‘fad’ like Atkins or Ducan style ‘diets’, but something that is being taken very seriously indeed on both sides of the Atlantic.
    As another correspondent has noted, you really should check your facts before writing such articles, especially as you are acting in an advisory capacity, albeit informally.

  6. Steve

    Your comments are entirely misleading and your headline ‘disastrous’ is shameful. Firstly, changes to the metabolism are exactly what are required, and ‘don’t mess the the metabolism’ in red is just plain wrong. Any diet leads to changes in the metabolism, otherwise there is no point whatsoever.
    Secondly, alternate day fasting and so called ‘yo yo’ dieting are two entirely different things and it is disingenuous to relate the two as you have done.
    Lastly – you refer to ‘the creators’ of this diet. It has no creators – the principles arose from many different sources of observation, notably irrefutable results such as the effect on longevity from the depression in the USA and the weight & fitness levels of Brits during and following the war years of rationing. ADF isn’t just about weight, but about growth hormone production & liver function, LDL levels, glucose levels and a great deal more. As more becomes known, it is becoming apparent that this could be extremely important for our health, so please do your research and revise this drivel.

  7. AG

    Horizon (BBC documentary series) recently did a programme on fasting, showing results from a clinical trial where people ‘fasted’ (500-600 cals) one day and ‘feasted’ (110% normal cal level) the next – the scientific results were very positive. The presenter of the documentary did a trial fast for 5 weeks of the 5:2 kind, 5 days normal, 2 days ‘fast’ and the results from his trial seemed also very good. This is scientifically backed research, do you have anything similar to back the claims up that ADF is as bad as you are claiming? Also what are your views on the 5:2 approach?

  8. Jesica

    Just Google “intermittent fasting” and you’ll find out it has many health benefits, aparts from weight loss.

    • ted

      This isn’t the same as intermittent fasting. Intermittent fasting involves eating NO calories on certain days.

  9. healthy diets

    Sounds interesting!
    I have never heard about the term and the concept of alternative dieting 🙂 But I enjoyed reading the article displaying such useful information for healthy diets. I think the dieting level from person to person differs. Weight and calories stand together. The metabolism activity of a person offcourse depends upon the diet he / she takes. So, I think dieting with particular amount of calory intake, which can be sometimes considered as extreme.

  10. Rachel, intern @ Eating Disorder Hope

    In many maladaptive eating patterns, diets, and eating disorders, there is a central theme that is sadly overlooked: nutrition. The idea of nutrition is often ignored or distorted in individual’s with eating disorders and for many pursuing recovery. This is why nutrition therapy is essential in the successful treatment of disordered eating. As you learn more about nutrition and eating disorders.

  11. Ben

    I think by managing a regular diet plans, and eating small meals throughout the day, 5-6 meals at 3-4 hour interval is a better way to lose weight than having a yo-yo diet. I believe the yo-yo diet is only encouraged if you are experiencing a plateau, and you need to break it through to bring the body to the next level.

  12. Linda

    Interesting article. Can ‘ t say I had heard of alternating dieting before. I’m with Dan on this one. Eating the same amount of calories daily, and regular exercise is what helped me lose 41lbs. Maintaining that loss is figuring out how many calories you can have daily without gaining. I weigh myself every morning to keep tabs on my weight and watch the calories that I’m eating. I think you have a better chance at not regaining the weight if you eat the same calories every day.

  13. Sue Knorr

    As a long time successful follower of the Zone diet I perfer moderation. Everything in moderation. Lowering inflammation and acheiving hormonal control are the basis of the Zone. The lower you body’s inflammation levels the easier it is for you body to lose its excess stored fat. The Zone works, and it’s easy. In fact it’s the only eating plan that has been sustainable for me. My whole family is thriving on the Zone diet and lifestyle. Artificial manipulation of the metabolism might stimulate weight loss (I have no idea if it does or not), but I doubt that would keep me healthy in the long run. Regarding the sentiment about tricking the brain into thinking it’s not dieting, sorry, but no thanks.

  14. Dan

    I basically vary my daily caloric consumption very very little. On most days, I consume about 3400 calories, which is considerably higher than what the calculator (which is linked here) calculated that I can consume, even given my high activity level. I figured this calorie level by slowly increasing my caloric consumption after reaching goal weight and figuring out what level of calories maintained my weight. When I was losing weight, I didn’t vary my caloric consumption that much. I have maintained a 95 pound weight now going on two years and I would partly credit not varying my caloric consumption that much on different days for being able to keep my weight
    almost completely steady. Never in my life of 51 years had I been able to do this- but then I never correctly counted calories after I had lost weight either. I am more precise in my count, because at home, I weigh and measure most foods that I eat. I also credit daily exercise for my weight loss and maintenance. I don’t vary the amount of exercise that I do each day very much, either. Not varying this does keep the calorie needs a bit more steady and predictable. When I do go over my calories when I go out to eat, I do more exercise and get back to the right number of calories all the days after and only go over when I go out to eat again.

  15. Spectra

    I don’t do anything that extreme, but I do find that alternating days of 1800 calories/day with days of 1400-1500 calories/day seems to help my body maintain its equilibrium. I don’t think alternating 1000 cals/day with 2000 cals/day would do any permanent harm, but it could be hard to stick to for a long period of time. I have a feeling many people would choose to eat 2000 calories more days than they should on a plan like that.

  16. Richard Perry

    I agree with finding your perfect calorie level & sticking to that until you reach your ideal weight. When I hear talk about speeding up or slowing down your metabolism my bs detector goes off.

    • Jim

      Personally I think you have to do whatever works. If this means a steady calorie level, or zig-zagging, or manipulating carb intake… whatever works.

  17. Jan

    Metabolism slows down after 2 days of continous fast so it will not hurt the metabolism

  18. Amy

    You contradicted yourself.

    “You would put your body in starvation mode one day…”

    “…the metabolism is not that sensitive. It takes years of following a specific calorie level to change the metabolism.”

    Your body does not go into “starvation mode” after one day.

    I’m not advocating this diet, just pointing out an inconsistency.

    • Nicole

      Yes, you are right. I suppose the point was to say that if you are trying to speed up or slow down the metabolism on this diet, you will not see an effect until after a few years.