# "It's unhealthy to lose weight too fast." Why? **URL:** \ **Category:** Factual Questions\ **Created:** [February 11, 2011, 6:07am UTC](https://boards.straightdope.com/t/its-unhealthy-to-lose-weight-too-fast-why/570995 "2011-02-11T06:07:28Z")\ **Posts on this page:** 20\ **Page:** 2
**Author:** ![Mangetout](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/mangetout/32/19_2.png) [@Mangetout](https://boards.straightdope.com/u/Mangetout)\ **Post date:** [February 12, 2011, 1:24am UTC](https://boards.straightdope.com/t/its-unhealthy-to-lose-weight-too-fast-why/570995/21 "2011-02-12T01:24:20Z")
> [@scamartistry](#): > > I think what you are missing is that we are evolved to be able to periods of starvation. Sure, and to live just long enough to procreate. Is that all you want? ---
**Author:** ![DSeid](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/dseid/32/20194_2.png) [@DSeid](https://boards.straightdope.com/u/DSeid)\ **Post date:** [February 12, 2011, 2:00am UTC](https://boards.straightdope.com/t/its-unhealthy-to-lose-weight-too-fast-why/570995/22 "2011-02-12T02:00:47Z")
> [@Fuzzy\_Dunlop](#): > > Rapid weight loss through very low calorie consumption while under a doctor’s care is a common treatment for obesity. [About very low calorie diets.](http://www.nature.com/oby/journal/v9/n11s/full/oby2001134a.html) They can be effective _if_ coupled with behavior therapy (BT) and long term support. Study results are, however, all over the place, and side effects are quite annoying. > [@](#): > > … dry mouth, constipation, headache, dizziness/orthostatic hypotension, fa-tigue, cold intolerance, dry skin, menstrual irregularities and hair loss. Most of these effects are directly related to the negative energy balance situation. In a study by Kirschner et al. (11), which analyzed 4026 dieters over more than 40,000 weeks with a 420-kcal VLCD, the most common problems were postural dizziness and tiredness. The most common complaint after prolonged use of VLCD was hair loss. More serious adverse events were exacerbation of gout (eight cases) and acute psychosis (four cases). In recent years reports were published about a potential larger than normal prevalence of cholelithiasis during VLCD use (12) … And while initial weight loss can be rapid, it typically slows: > [@](#): > > VLCDs have been shown to be very effective in the treatment of obesity. An average weekly weight loss of approximately 2.0 kg in the first 4 to 6 weeks slows to an average weekly weight loss of approximately 0.8 kg over a 6-month period. VLCDs and LCDs with an average intake between 400 and 800 kcal/d do not result in differences in body weight loss, as shown in some RCTs. Therefore, the pessimistic 1958 view of Stunkard and McLaren-Hume (1), that most patients will not lose weight, is no longer true. However, their statement that most patients regain their lost weight is still true. FWIW. ---
**Author:** ![rhubarbarin](https://avatars.discourse-cdn.com/v4/letter/r/eb9ed0/32.png) [@rhubarbarin](https://boards.straightdope.com/u/rhubarbarin)\ **Post date:** [February 12, 2011, 2:02am UTC](https://boards.straightdope.com/t/its-unhealthy-to-lose-weight-too-fast-why/570995/23 "2011-02-12T02:02:01Z")
> [@scamartistry](#): > > If you are reasonable healthy (which I am sure the Dr have checked in detail), you can go weeks without food. No problem. Now if you are fat as a pregnant whale, you could probably go months. Understand how much energy that flabbery fat represent. They could survive solely on water and vitamin pills. > > What would they die of according to you? > > I think what you are missing is that we are evolved to be able to periods of starvation. Plenty of people die from extended intensive exercise, including seasoned marathoners and other very fit and athletic people. This is what I’m worried about. Semi-starvation diets causes many other serious health effects, many of them psychological and potentially very long-lasting (google ‘starvation study’ sometime). But I don’t think not eating very much (and mostly crap, from what I have seen - the show is one big General Mills ad) for the duration of the show is going to kill them - it’s just not good for their bones, muscles, heart, organs, for the ability to maintain a menstrual cycle, or if they don’t want to lose their hair in handfuls. ---
**Author:** ![Roderick\_Femm](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/roderick_femm/32/14875_2.png) [@Roderick\_Femm](https://boards.straightdope.com/u/Roderick_Femm)\ **Post date:** [February 12, 2011, 6:18am UTC](https://boards.straightdope.com/t/its-unhealthy-to-lose-weight-too-fast-why/570995/24 "2011-02-12T06:18:35Z")
> [@medstar](#): > > Congratulations on your success, Roddy, and your ongoing commitment to stay slim. I’d like to ask a personal question if I might? Do you have any issues with hanging skin? Did it shrink at all or will you need some cosmetic surgery to get rid of it? I’m asking being because I’m obese and I’d like some hope that as I lose weight, maybe my skin will shrink (at least a little). I have residual subcutaneous fat, along with some visceral fat that has crept back in. I have man boobs, smaller than when I was fat, and a spare tire on both sides, that I have always had. But I also have a sort of pouch in the front where my stomach was biggest. It’s not just skin, there is also some fat, but if I draw it up with my hands, my stomach looks like it did when I was young and slim. I’m far from an expert, but I think whether you will have sagging skin after losing a lot of weight depends on these things: your age (skin elasticity almost certainly is reduced with age); how much exercise you get, especially things that strengthen your core; and possibly how fast you lose the weight. The better the first two things are, the faster you can probably lose weight with less risk of sagging skin. In the program I was in, they brought in a plastic surgeon to talk about removing excess skin after weight loss, and after seeing the before-and-after photos I was not interested. He specialized in whole body lifts, where he would make a big incision across your ribcage or above your chest, and just pull everything up, cut off the excess, and sew you up. You do look a lot better in clothes, but the scarring was really something, and the doctor said it never goes away, although it does fade in time. (His examples were all older people, by the way.) If the sagging skin is not too extreme there are smaller cosmetic procedures that can be done, if you want to spend the money. For example, at least one practice in my area advertises reduction of man boobs as a specialty. But please, if you have the opportunity and the will to lose weight, don’t let the potential of sagging skin hold you back. Maybe you won’t be more beautiful than you are now. But you will feel so much better, you will be healthier and happier every single day. Don’t do it for romance or sex, do it for all those minutes of every day when your weight is holding you back from doing things that you want to do - if that is the case. If you are not unhappy being overweight, then please ignore these comments, because you have to be pretty desperate to go through this and stick with it. If anyone wants to know the program I participated in, PM me and I will tell you, and they might be able to give you a reference in your area (I’m in San Francisco). There are programs like this all through the country. It’s not easy, but I think it’s a lot better than the last resort, which is bariatric surgery (I hope I spelled that right, the dictionary doesn’t like it). Good luck, Roddy ---
**Author:** ![Weedy](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/weedy/32/301_2.png) [@Weedy](https://boards.straightdope.com/u/Weedy)\ **Post date:** [February 12, 2011, 10:27am UTC](https://boards.straightdope.com/t/its-unhealthy-to-lose-weight-too-fast-why/570995/25 "2011-02-12T10:27:42Z")
> [@pepperlandgirl](#): > > Well, I’m not using a magazine, diet pill, or the health food business. I ate a lot of junk food on a regular basis. I cut out all the junk food, the mindless snacking, and I’m getting help with my issues that lead to binge eating. I’m also getting in the habit of starting my day with a good walk. Sometimes people lose weight very quickly when they change their lifestyle, like 5-10 lbs a week. Usually only for the first few weeks, then it slows down. ---
**Author:** ![DSeid](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/dseid/32/20194_2.png) [@DSeid](https://boards.straightdope.com/u/DSeid)\ **Post date:** [February 12, 2011, 5:46pm UTC](https://boards.straightdope.com/t/its-unhealthy-to-lose-weight-too-fast-why/570995/26 "2011-02-12T17:46:21Z")
[A more recent review of Very Low Calorie Diets](http://www.nature.com/oby/journal/v14/n8/full/oby2006146a.html). > [@](#): > > VLCDs are considered safe and effective when used by appropriately selected individuals under careful medical supervision (5). The diets are designed for patients with a BMI 30 kg/m2, a group at increased risk of cardiovascular morbidity and mortality and that also may derive the most benefit from substantial weight loss. In the United States, all candidates for a VLCD are expected to undergo a history and physical examination to determine medical and behavioral contraindications to treatment, as described in previous reviews (5, 7). As noted previously, a similar recommendation applies in Europe to individuals who have significant comorbidities (1). > Patients in medically supervised VLCD programs in the U.S. are monitored by a physician approximately every 2 weeks during the period of rapid weight loss (i.e., 1.5 to 2.5 kg/wk). During this time, they are at increased risk of gallstones, cold intolerance, hair loss, headache, fatigue, dizziness, volume depletion (with electrolyte abnormalities), muscle cramps, and constipation (5, 15, 16, 18). These side effects are usually mild and easily managed. … > > … Unsupervised use of VLCDs can result in serious complications, including death … > > … The NHLBI expert panel did not recommend the use of VLCDs over LCDs providing 1000 to 1500 kcal/d of conventional foods (6). The panel’s conclusion was based on data from randomized trials that showed no differences in long-term weight losses between VLCDs and LCDs, principally because of greater weight regain after VLCDs (6). … > > … This meta-analysis of six studies showed that VLCDs induced significantly greater short-term weight losses than LCDs but comparable long-term changes in weight. The equivalence of long-term losses was attributable to greater weight regain among the VLCD-treated patients. The present findings support the conclusion of the NHLBI expert panel that VLCDs not be recommended in lieu of LCDs comprised of conventional foods (6). … > > … Together, these findings suggest that efforts to maintain mean weight losses of 15% to 25% of initial weight are unlikely to be successful in a majority of patients, given current behavioral therapy and behavioral and pharmacologic therapies (i.e., sibutramine and orlistat). Factors responsible for weight regain after treatment with VLCD may include behavioral fatigue (60) in adhering to rigorous diet and exercise regimens in the presence of a toxic environment, as well as compensatory changes in peripheral and central hormones that regulate appetite and energy expenditure (61, 62, 63). At present, bariatric surgery appears to be the only reliable method of sustaining weight losses of 20% or more of initial weight (64). … **Roderick** , both your success and your rate of loss are admirable and exceptional. In particular, your ability to stick with the lifestyle changes to that degree after weight loss makes you really stand out from the pack. It is that unusual achievement of yours that most interests me. Some of it may be your personal strength of will, but I suspect that you did other things both to have the support you needed and to change your personal environment in ways that made it achievable, things that even those who aim to maintain more modest fat loss but lasting behavioral changes would do well to emulate. Could you share the specific things you have done and do to help you maintain your victory in that “constant struggle”? ---
**Author:** ![D-bear](https://avatars.discourse-cdn.com/v4/letter/d/aeb1de/32.png) [@D-bear](https://boards.straightdope.com/u/D-bear)\ **Post date:** [February 13, 2011, 11:34pm UTC](https://boards.straightdope.com/t/its-unhealthy-to-lose-weight-too-fast-why/570995/27 "2011-02-13T23:34:28Z")
> [@si\_blakely](#): > > And all credit to **Roderick Femm** - one hell of an achievement. But it was medically supervised to ensure that the rapid weight loss did not cause additional damage. If you are not being monitored carefully, a slower rate of weight loss is safer. > Si I have to second this. I started Optifast on August 23rd. I’ve lost 102.8 pounds. I had weekly medical consultations with periodic blood-work, EKG, Cholesterol, Blood Sugar monitoring, the whole works. Add to that weekly education and 1 year of after program support group sessions. Expensive? Yes. Worth it? Well, we’ll see how long this works. After August 23rd, 2011 if I have lost the remaining 50 pounds and manage to keep it off, I’ll say yes. The rapidness of the loss didn’t hurt my health. I can say so since I was so closely monitored. 900 calories a day for 21 weeks. I would NEVER recommend doing it unsupervised. Starting weight = 352.6 After 21 weeks = 256.1 (official end of program) Weight today = 249.8 YMMV ---
**Author:** ![DSeid](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/dseid/32/20194_2.png) [@DSeid](https://boards.straightdope.com/u/DSeid)\ **Post date:** [February 14, 2011, 11:33pm UTC](https://boards.straightdope.com/t/its-unhealthy-to-lose-weight-too-fast-why/570995/28 "2011-02-14T23:33:55Z")
Wow. What are _your_ plans to keep up the support to keep up the lifestyle changes long term? What have you done to change your environment systematically to not fall back into previous routines? Seriously. I know that people can lose weight, even dramatic amounts of weight, but how will you react if you start gaining again and what do you do to keep your medical risks reduced long term, after the constant reinforcement of seeing the scale number decrease is no more? A few people pull that, a much more difficult part, off. I’d love to know how they do it. In concrete terms. ---
**Author:** ![D-bear](https://avatars.discourse-cdn.com/v4/letter/d/aeb1de/32.png) [@D-bear](https://boards.straightdope.com/u/D-bear)\ **Post date:** [February 15, 2011, 4:08am UTC](https://boards.straightdope.com/t/its-unhealthy-to-lose-weight-too-fast-why/570995/29 "2011-02-15T04:08:53Z")
Well, my “family” consists of me and my Husband. We started this program together and removed ALL food from our house. He lost 60 pounds in this program. (We, both being male were able to lose weight easily to the chagrin of the ladies in our group.) One big motivator was the cost of the program. It was $3,100 for each of us. We’re both notoriously tight with a dollar. Every time I’m tempted by Del Taco or some other such junk, I think about the money invested in getting the weight off ant that keeps me on the straight and narrow. The Support group portion is paid for as part of the program. (We were paid in full as of 1/21) and runs for a year from the last official day on program (or through 1/21/12) and so far it’s been enough to keep me accountable. I also have a body bug to keep me honest as far as getting my daily allotment of daily activity. I’m committed. I’ve lost the same 100 pounds 3 times now and this seems to be working, but it’s one-day-at-a-time for now. I really want to be healthy. I think that is a good motivator too… The [Optifast](http://www.optifast.com/Pages/optifast_home.aspx) website has some interesting info on it. I made some really GOOD friends in my group too as an added bonus… ---
**Author:** ![Superhal](https://avatars.discourse-cdn.com/v4/letter/s/b4bc9f/32.png) [@Superhal](https://boards.straightdope.com/u/Superhal)\ **Post date:** [February 15, 2011, 9:46am UTC](https://boards.straightdope.com/t/its-unhealthy-to-lose-weight-too-fast-why/570995/30 "2011-02-15T09:46:32Z")
Another reason (learned from an episode of House): Some common environmental toxins are stored in fat. As you lose weight, the toxins in the fat are released back into the body. Normally, the amounts are so minuscule that you won’t be harmed, but excessive weight loss in a very short amount of time can cause an unhealthy amount of that toxin to be released. Not sure if it’s true but it made for an interesting episode. 😃 ---
**Author:** ![even\_sven](https://avatars.discourse-cdn.com/v4/letter/e/dfb087/32.png) [@even\_sven](https://boards.straightdope.com/u/even_sven)\ **Post date:** [February 15, 2011, 1:26pm UTC](https://boards.straightdope.com/t/its-unhealthy-to-lose-weight-too-fast-why/570995/31 "2011-02-15T13:26:49Z")
> [@rhubarbarin](#): > > Semi-starvation diets causes many other serious health effects, many of them psychological and potentially very long-lasting (google ‘starvation study’ sometime). But I don’t think not eating very much (and mostly crap, from what I have seen - the show is one big General Mills ad) for the duration of the show is going to kill them - it’s just not good for their bones, muscles, heart, organs, for the ability to maintain a menstrual cycle, or if they don’t want to lose their hair in handfuls. 1,500 calories is hardly “semi-starvation.” ---
**Author:** ![Great\_Antibob](https://avatars.discourse-cdn.com/v4/letter/g/e47c2d/32.png) [@Great\_Antibob](https://boards.straightdope.com/u/Great_Antibob)\ **Post date:** [February 15, 2011, 4:03pm UTC](https://boards.straightdope.com/t/its-unhealthy-to-lose-weight-too-fast-why/570995/32 "2011-02-15T16:03:38Z")
> [@even\_sven](#): > > 1,500 calories is hardly “semi-starvation.” Sure, for a 5’ tall woman weighing 90 lbs. For a morbidly obese 6’ tall man, it may be cutting it close. You don’t want these people entering starvation mode, after all. ---
**Author:** ![Philster](https://avatars.discourse-cdn.com/v4/letter/p/13edae/32.png) [@Philster](https://boards.straightdope.com/u/Philster)\ **Post date:** [February 15, 2011, 4:17pm UTC](https://boards.straightdope.com/t/its-unhealthy-to-lose-weight-too-fast-why/570995/33 "2011-02-15T16:17:33Z")
“Starvation Mode” is a short-lived condition. Ultimately, you’re body can’t hoard calories and has to burn fuel to survive. ---
**Author:** ![Fuzzy\_Dunlop](https://avatars.discourse-cdn.com/v4/letter/f/848f3c/32.png) [@Fuzzy\_Dunlop](https://boards.straightdope.com/u/Fuzzy_Dunlop)\ **Post date:** [February 15, 2011, 4:40pm UTC](https://boards.straightdope.com/t/its-unhealthy-to-lose-weight-too-fast-why/570995/34 "2011-02-15T16:40:25Z")
> [@DSeid](#): > > Wow. > > What are _your_ plans to keep up the support to keep up the lifestyle changes long term? What have you done to change your environment systematically to not fall back into previous routines? > > Seriously. I know that people can lose weight, even dramatic amounts of weight, but how will you react if you start gaining again and what do you do to keep your medical risks reduced long term, after the constant reinforcement of seeing the scale number decrease is no more? > > A few people pull that, a much more difficult part, off. I’d love to know how they do it. In concrete terms. For one thing you should continue to work with your doctor, albeit with longer and longer breaks between visits. I lost about 40 pounds over 6 weeks on a very low calorie diet and another 25 since then. I would like to lose another 15 pounds but am pretty content to lose it very slowly. Everyone says I look great - I’m not sure if that’s relative to how heavy I was or if people are just used to thinking someone 15 pounds overweight is a healthy weight. Probably both. But bottom line, while I plan to reach my goal I no longer have the aesthetic issue burning the desire to do it quickly. Medically, my cholesterol levels have all gone from high to optimal, except for HDL which is acceptable. I’ve been able to cut my BP meds in half. Most of my family is very slender and half of them still take BP medication, so I think unfortunately it’s just a problem for our family. Speaking only for myself, my diet had become generally pretty nutritious for years. My weight was stable for about 10 years, having put it all on beginning pre-puberty and continuing to add weight and fat in my teenage years while I had a really lousy diet. I tried to lose weight through college and in my early 20s but only maintained it at a steady level. For several years since college as my life got more stable it’s been really pretty healthy with lots of vegetables and very few processed food. Clearly I was eating too much while trying to lose weight, but I was eating too much healthy food and was not gaining more weight. I’ve never “yo-yo’d” ever. I tried to lose weight in the past and completely failed. I honestly don’t know why I failed for years but it’s been quite easy since I started working with this doctor. As far as long term maintenance, as I said, I haven’t changed my lifestyle drastically. I eat much less but there’s a lot less of me, so I’m not as hungry. I did make some substantial changes to my diet but it’s not like I went from fritos to broccoli. One thing I think is significant, for me, is that I now have a healthier attitude about food. As an example, I’ve always loved seafood, but I never bought it to cook at home because it’s pricier per pound than a lot of other protein. Spending extra money on food was hard to justify psychologically, since ultimately food just contributed to being obese which was my single biggest problem in life. But fish, cooked appropriately, is a really great protein and now that I’m close to a healthy weight I’m happy to buy and cook it. I would have been better off eating that way all along, but didn’t have the right mindset. ---
**Author:** ![Great\_Antibob](https://avatars.discourse-cdn.com/v4/letter/g/e47c2d/32.png) [@Great\_Antibob](https://boards.straightdope.com/u/Great_Antibob)\ **Post date:** [February 15, 2011, 5:06pm UTC](https://boards.straightdope.com/t/its-unhealthy-to-lose-weight-too-fast-why/570995/35 "2011-02-15T17:06:22Z")
> [@Philster](#): > > “Starvation Mode” is a short-lived condition. Ultimately, you’re body can’t hoard calories and has to burn fuel to survive. My actual point was only that starvation for one person is perfectly adequate sustenance for another. For me, 1500 calories a day would not be starvation level. For a 600 pound person, it’s potentially dangerous, unless medically supervised. I could be wrong, but the post I originally replied to seemed to blithely dismiss just how different the metabolism of a morbidly obese person is from a person of healthy weight. ---
**Author:** ![rhubarbarin](https://avatars.discourse-cdn.com/v4/letter/r/eb9ed0/32.png) [@rhubarbarin](https://boards.straightdope.com/u/rhubarbarin)\ **Post date:** [February 15, 2011, 9:00pm UTC](https://boards.straightdope.com/t/its-unhealthy-to-lose-weight-too-fast-why/570995/36 "2011-02-15T21:00:09Z")
> [@even\_sven](#): > > 1,500 calories is hardly “semi-starvation.” It has certainly been considered to be in scientific literature, at least for overweight people and men of normal size and activity level. See the [Minnesota Starvation Experiment.](http://en.wikipedia.org/wiki/Minnesota_Starvation_Experiment)Subjects (all fit, lean young men) had a normal calorie intake of around 3000 calories, to cut that in half is quite drastic. In this case the semi-starvation portion was modeled after the starvation rations of soldiers during the war. Results were extreme weight loss along with many other health problems, including developing eating disorders and going so batshit crazy they did things like cut off their fingers. For me, 1500 calories would cause fairly rapid weight loss, since I need at least 2500 cals per day to maintain my current weight, 105 lbs (a few pounds underweight by BMI). Of course I’m very far from your ‘average’ person. ---
**Author:** ![pulykamell](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/pulykamell/32/3166_2.png) [@pulykamell](https://boards.straightdope.com/u/pulykamell)\ **Post date:** [February 15, 2011, 9:16pm UTC](https://boards.straightdope.com/t/its-unhealthy-to-lose-weight-too-fast-why/570995/37 "2011-02-15T21:16:54Z")
> [@rhubarbarin](#): > > It has certainly been considered to be in scientific literature, at least for overweight people and men of normal size and activity level. See the [Minnesota Starvation Experiment.](http://en.wikipedia.org/wiki/Minnesota_Starvation_Experiment)Subjects (all fit, lean young men) had a normal calorie intake of around 3000 calories, to cut that in half is quite drastic. In this case the semi-starvation portion was modeled after the starvation rations of soldiers during the war. Results were extreme weight loss along with many other health problems, including developing eating disorders and going so batshit crazy they did things like cut off their fingers. > > For me, 1500 calories would cause fairly rapid weight loss, since I need at least 2500 cals per day to maintain my current weight, 105 lbs (a few pounds underweight by BMI). Of course I’m very far from your ‘average’ person. Interesting. I’m a 5’11", 165-170 lb male, and 2500 calories a day will cause my weight to maintain (if I’m reasonably active) or creep (if I’m mostly laying about, like right now in the winter.) You seem to have a pretty good metabolism and probably are quite active. ---
**Author:** ![Sleel](https://avatars.discourse-cdn.com/v4/letter/s/73ab20/32.png) [@Sleel](https://boards.straightdope.com/u/Sleel)\ **Post date:** [February 16, 2011, 5:52am UTC](https://boards.straightdope.com/t/its-unhealthy-to-lose-weight-too-fast-why/570995/38 "2011-02-16T05:52:08Z")
I generally agree that losing weight too quickly is unhealthy, but I disagree with a few points in an earlier post. A ketogenic diet is not unnatural, and not unhealthy. The essential dietary carbohydrate intake in a human diet is _zero_. [[http://www.ajcn.org/content/75/5/951.2.full](http://www.ajcn.org/content/75/5/951.2.full)] The necessary blood glucose can be generated through gluconeogenesis. The traditional Eskimo diet had virtually no carbohydrate component and they didn’t have cardiovascular disease, obesity, or diabetes until they adopted a more Western diet. In contrast with the modern diet where ketosis is associated with a caloric deficit, most hunter-gatherer diets feature periods of ketosis even when calories are sufficient due to the dearth of high-glycemic load foods in the wild. Actually, most traditional diets only fall back on starchy foods as a hedge against starvation when protein and fat sources—which are mostly from animals—are scarce. So the argument could be made that the carbohydrate intake in a modern diet is unnatural and having various periods of ketosis and glycolysis is the ancestral norm. There’s a detailed discussion of the Stefansson study (also mentioned in the Straight Dope report on the Eskimo diet and scurvy) in Taube’s Good Calories, Bad Calories, where he discusses how strict the study was; you wouldn’t be able to do a study that featured such a rigorous and controlled environment under current human subject research guidelines. Stefansson lived in the lab for over a month, eating nothing but what researchers provided, and he had to provide periodic blood and urine samples during the course of the year-plus long study to provide proof that he was still in ketosis, and to track his health indicators. A ketogenic diet has long been recognized as theraputic for the prevention of seizures. There are also indications that periodic ketosis provides neuronal protection and stimulates recovery from injury [[http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2824219/](http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2824219/)] may provide protection and have theraputic use in the treatment of alzheimers [[http://multivu.prnewswire.com/broadcast/36441/36441-Henderson2008Neurotherapeutics.pdf](http://multivu.prnewswire.com/broadcast/36441/36441-Henderson2008Neurotherapeutics.pdf)] and can stimulate chaperone-mediated autophagy (a cellular repair mechanism). The inhibition of CMA is associated with renal hypertrophy in studies with diabetic rats [[http://www.nature.com/ki/journal/v65/n6/abs/4494514a.html](http://www.nature.com/ki/journal/v65/n6/abs/4494514a.html)]. The degradation of CMA processes has also been recognized as an underlying cause in neurodegenerative disorders [[http://www.springerlink.com/content/p62n80522xrr17u3/](http://www.springerlink.com/content/p62n80522xrr17u3/)] On-topic, the main reason for not going on a crash diet is sustainability. If you want to lose fat and keep it off, need to be eating that way basically forever. If you can’t maintain the diet, you will regain the weight. Very low calorie diets are not sustainable in the long term. You need to adjust to a more realistic intake eventually. Where most people screw up is in going back to their old eating habits instead of eating adequate calories in the form of healthy food. ---
**Author:** ![Roderick\_Femm](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/roderick_femm/32/14875_2.png) [@Roderick\_Femm](https://boards.straightdope.com/u/Roderick_Femm)\ **Post date:** [February 16, 2011, 7:30pm UTC](https://boards.straightdope.com/t/its-unhealthy-to-lose-weight-too-fast-why/570995/39 "2011-02-16T19:30:06Z")
> [@DSeid](#): > > [A more recent review of Very Low Calorie Diets](http://www.nature.com/oby/journal/v14/n8/full/oby2006146a.html). > **Roderick** , both your success and your rate of loss are admirable and exceptional. In particular, your ability to stick with the lifestyle changes to that degree after weight loss makes you really stand out from the pack. > > It is that unusual achievement of yours that most interests me. Some of it may be your personal strength of will, but I suspect that you did other things both to have the support you needed and to change your personal environment in ways that made it achievable, things that even those who aim to maintain more modest fat loss but lasting behavioral changes would do well to emulate. > > Could you share the specific things you have done and do to help you maintain your victory in that “constant struggle”? Thanks, it is statistically unusual, but I do know a number of people in this program who have done as well or better. Here’s what I do, and the success of this approach has some research behind it: 1. I attend maintenance groups once a week (or as close to that as I can) in the same program where I lost the weight. I have tried being on my own, and it just doesn’t work for me. Maybe it’s the discipline of that voluntary weekly weight-in. 2. I keep track of all the food I eat. After 5 years I am pretty good at estimating volume and calories, but a food scale is also very handy. I also use an app on my Droid phone called myfitnesspal, which has access to an online database of foods, especially brand name or chain restaurant foods, which really helps. Let me emphasize: this step is critical. It keeps you honest. 3. Regular exercise, that I talked about before. There is a recommended minimum of exercise, I think around 2800 calories per week for men. I do about 75% more than that on average. If you do those three things your chances of maintaining weight loss are, I think, much better. There are also a ton of other smaller things, that we learn about in our weekly meetings, like weighing yourself regularly, and not sabotaging yourself psychologically, which is one of the most common problems. My own determination to keep my weight off is also colored by the fact that I went back on the (expensive) weight loss program twice already since the first time, and I really don’t want to do that again. Plus how much better I feel when I’m at a good weight versus adding even a few pounds. I have also managed to get past the notion that it’s not fair that I have to work this hard to keep the weight off, when people who were never fat don’t have to worry about it. It’s not fair, but that is the way it is. I’m responsible for every calorie that goes in my mouth, including all the ones that went in when I was getting fat. I give in to cravings from time to time and eat things I shouldn’t eat. I write everything down, and I don’t make excuses. I could go on for days. Sorry if this is too long. Roddy I forgot to add: my partner has been very supportive, although it never bothered him when I was fat. He does the cooking, and he cooks very healthy stuff for me now - it’s easy stuff, like grilled chicken and steamed vegetables, but I really appreciate his help. He also doesn’t seem to mind all the time that I spend at the gym. If he had not been supportive or if he had tried to sabotage me in some way (which happens to some people) it would have been much harder. ---
**Author:** ![DSeid](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/dseid/32/20194_2.png) [@DSeid](https://boards.straightdope.com/u/DSeid)\ **Post date:** [February 17, 2011, 2:22pm UTC](https://boards.straightdope.com/t/its-unhealthy-to-lose-weight-too-fast-why/570995/40 "2011-02-17T14:22:36Z")
Thank you. Too many keep losing the same 100 pounds over and over again. Having very specific ideas of how to keep running, forever as a matter of conscious lifestyle decision making, after you feel you’ve crossed the marathon’s finish line and long after everyone has stopped congratulating you, seems key. [Previous page](https://boards.straightdope.com/t/its-unhealthy-to-lose-weight-too-fast-why/570995.md?page=1) [Next page](https://boards.straightdope.com/t/its-unhealthy-to-lose-weight-too-fast-why/570995.md?page=3)