In my own experience, vlcd's have contributed far more to weight gain than to weight loss. When I gave them up for good, my weight gain stopped. If I had never gone on a vlcd, I do wonder whether my highest weight would have been anything close to 394 lbs.
There is a quite substantial amount of research that has established that vlcd's are associated with substantial health risks including organ damage and cardiac arrest. Also gallbladder and immune system damage.
Vlcd's are also psychologically (and perhaps even physiologically) "addictive."
Weight loss surgery patients are actually a great example of what vlcd's do to your immune system. If vlcd's did not adversely affect metabolism, then bypass patients would not have to change their eating habits or calorie intake. Bypass surgery bypasses parts of the digestive system where calories are absorbed. As a result, a bypass surgery patient should be able to lose at least some weight without changeing their diet at all.
In fact, for a bypass patient to regain all of the weight lost by surgery, they would hae to eat far more than they did before the surgery - but this isn't what happens.
Except for the most drastic of surgeries, success rates for weight loss surgeries vary from 40% to 60%. That means that about half or more of wls patients return to their original weight or higher - so they must be eating much more than they were before the surgery, right? That would be the only plausible reason if wls did not decrease metabolic rate - but that's not what happens.
Wls does slow metabolism, it just doesn't slow it enough to prevent weight loss. The most effective aspect of wls is assisting a person in reducing calorie absorption faster than the vlcd can lower metabolism.
There are risks associated with vlcd's (and wls, for that matter, but that's a different issue).
Unfortunately, my memory for specific studies isn't what it used to be, and I no longer keep a file of relevant research, but I have just started reading a book you might find helpful:
The Smarter Science of Slim: What the Actual Experts Have Proven About Weight Loss, Dieting, & Exercise, Plus, The Harvard Medical School Endorsed Program To Burn Fat Permanently - Jonathan Bailor (Author)
What I love about this book is the amount of research cited. I don't think I've ever read a book or research article or even graduate degree thesis with so much cited research. This doesn't necessarily prove the author's arguments, but the citations allow the reader to go to the original research and decide whether the research supports the author's arguments.
I was always under the impression that the "1200 floor" was just the average amount, but that some individuals may take in more or less without any ill effects. It would depend on things like height, genetics, activity level, etc anyway, wouldn't it?
Exactly correct.
Obviously the nutrtional needs of a 18 year old 6'9" active male are going to be quite different than a 63 year old 4'11" sedentary female.
I agree with most of the replies here. I believe (and I'm no MD or nutritionist) that the number is a general idea about how many calories the body needs to survive. That number varies by person.
I'm not going to argue whether below 1200 is physically dangerous because I don't have the background to.
However, I will argue that weight loss can suffer on a low calorie diet because it's difficult to be sustainable over a long period of time. Some people can eat 1200 or less just fine for months at a time, where some cannot and end up giving up.
My personal goal is to eat around 1200. Sometimes that is higher and sometimes that is less, but it varies.
So, 4star, does that mean if I'm eating 60 g of protein a day (I see that often as the minimum amount) and doing lots of strength training and taking a multivitamin, I should be good, even if I'm only consuming 800 - 1000 calories per day? I get minimum levels of fat, but I don't avoid carbs at all, since I get most of them in "natural" form, like fruits and veggies.
Most of the "reasonable" Very Low Calorie Diets are Doctor supervised to make sure that the diet isn't over-taxing the body. With too low carbs and too high protein, your liver can start to see taxing. With too low carbs, serotonin levels can drop and depression can set in. With too low fat, your brain can't function as well. It's all important to keep balanced. I like to think of it this way, I can eat apples all day, be full and lose weight but it's not a balanced diet and soon it will take it's toll and cause imbalance.
IMHO, I think it's better to eat a slightly higher amount of calories and build the muscle so that if you have an injury or go on vacation where it's harder to calculate calories, you will still have your momentum from your metabolism being charged so your body can meet the demand of more food to process.
Doctor's pick the number 1200 b/c that is approximately the amount of calories needed for an adult's body to maintain it's metabolic functions, if you were to do nothing all day. ANYONE can lose weight on 1200 calories.( I can lose 4.6 pounds a week with no exercise but only until exhaustion set in by the end of a month b/c it's just too low for what I need to do everyday.) If you go to your doctor and tell them you think you have a metabolic disorder, they may ask you to try a 1200 cal a day diet. In my experience it can verify for you that you CAN lose weight by calorie restriction but it's more of a "test" number b/c lower than that would indicate metabolic damage. It's ridiculously low for an average person.
What I think needs to be considered is longevity. Will you be content to eat a very low calorie allotment indefinitely or is it better to eat a few more hundred a day to go slower and train your body to meet the higher metabolic demand?
There are no exact number for anyone as far as proteins, fats and carbs go. It's one of those things you have to feel out. Personally, I can eat 1750 calories of protein dense foods and have much more weight loss than 1750 calories of carb dense foods but that's my body, carb-sensitive. Others might tell you that they need a higher amount of carbs to feel happy. It's all true. What I think works well is to see where you are on calories and how you spend them and then reduce and/or rearrange your calories to meet you weight loss goals. I would recommend noting your daily moods and energy levels as well as food so you can pinpoint your sweet spot.
Just thought I'd add maybe another way to look at things, this information is from the New Rules of Lifting for women book that I've read (currently doing the program). It says:
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A combination of "eat less" and "exercise more" is the physiological equivalent of "I voted for it before I voted against it". It takes 2,800 calories to build a pound of muscle. If you're slicing 3,500 calories a week from your diet while at the same time engaging in a workout program designed to increase strength and build new muscle tissue, from where will you get those 2,800 calories?
Let's look at it another way. You need 454 grams of protein to create a pound of muscle tissue. If you're eating 2,000 calories a day and 30 percent of those calories come from protein that's 4,200 calories a week from protein, or 1,050 grams. But if you cut down to 1,500 calories a day, and keep protein intake constant at 30 percent of total calories, you're now getting 3,150 calories a week from protein, or 787 grams.
That looks like enough to build muscle, until you consider that your body is already shedding and adding protein to your muscles every minute of every day. The technical phrase is "protein turnover". It happens even if you don't exercise - and if you do, the process accelerates. That's why 787 grams of protein isn't nearly enough to support exercise-induced protein turnover while giving you a net gain in muscle size.
The point is simple, if the sample women is eating 1,500 calories a day, the best she can hope for is that she breaks even - her body uses as much protein as she eats and no more. But that's unrealistic. First, it's unlikely that her body would need just 70 grams of protein a day on a weight-loss diet. When you cut calories, suddenly your body is looking for energy wherever it can find it, and that probably means she'll use some of that dietary protein for energy. Second, it's entirely possible that she'll use some of the protein already stored in her muscles to make up for the energy deficit.
Everyone who's ever cut calories on a diet fantasizes that her body will use stored body fat to replace the missing energy, but the reality is that muscle is lost along with fat. The only way to preserve muscle tissue when drastically cutting calories is to eat a lot of protein. There's no way to know for sure, but I'd guess that even the highest estimate of protein needs that I've shown here - 140 grams a day - would be cutting it close.
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I know that's a lot of information, but it might be helpful to some of you. If you just want to lose weight right now, and your body feels good on low calories, then why not. Listen to your body. But if one day your goal is going to be to gain strength etc., you're going to have to eat more. I think it's pretty safe to say that it's just science in terms of how your body works. The book has a ton of information, and what i've quoted is just a tiny part.
All I can tell you is that I've been on Medifast for over a year. My daily average is around 1100 calories. I have my doctor's blessing, I feel great, and I'm still motivated to continue.
I also think it matters what you eat. I'm hypoglycemic, and could never manage on a low calorie/low fat/more carb diet. The Medifast works for me because it has more protein and less carbs.
While "no lower than 1200 calories" may be the rule, I think there are lots of exceptions to the rule.
This is actually incredibly helpful information. Thanks for the book recommendation, Kaplods. (I always find your posts incredibly insightful anyway.) Thank you for the extremely helpful and thoughtful response, 4star. And Smad, your response breaks it down so comprehensively, I feel like I'm at last getting a good grasp on things. And I've read A LOT of nutrition information. Bargoo and Stephanie - that's actually what I ask myself virtually every day. Will I be comfortable staying at this rate the rest of my life? I have three sisters who have all gone the surgical route, and I am considering it right now, so I just tell myself that self-imposed calorie restriction is a lot better than drastic surgery -- if I can maintain the regimen without the surgery. I have never had ANY success with moderation, though, so I'm nervous about shaking it up. (I lost almost 100 pounds this way a few years ago, though obviously I didn't maintain it. But after numerous attempts at "moderation," I concluded that I'd rather risk possible future regain than continue at the rate I was going.)
Seagirl - I don't want to be "thin." I want to be strong and healthy. I have consciously decided not to weigh every day, because I don't want to discourage myself from sticking with strength training, which often results in short term gains. Thanks to smad's analysis, I have a better idea of how to actually accomplish that.
Riddy - I actually have sort of built my plan after what I understood of Medifast. Yet another reason why it seemed not that big of a deal to have such a low calorie intake. =)
So, I guess I am going to talk to my doctor. My inclination is just to drastically increase my protein, but I have had kidney stones in the past, so maybe that's not really the best long-term solution. Blech. I don't think he's ever been overweight, and the best he's given me when I've asked for advice in the past is, "Don't drink soda or juice." Yep - because that's every overweight person's problem, and the answer to this complex obesity problem. But perhaps he can at least give me a referral to someone who might actually have some knowledge instead of irritating platitudes.
Y'all are really the best.
Last edited by LaurieDawn; 06-27-2012 at 11:24 PM.
Very helpful responses; thank you all. I've a feeling this post ought to be stickied. On the whole I'm feeling less worried about my calorie intake now, but I too will give the doctor a ring and see if I can go in for a chat and make sure everything's all good.
Bargoo raised an interesting point - what happens when we reach target and have to maintain? I've been wondering about this recently, and can see two options. First, calorie intake and weight eventually reach equilibrium (though I suspect this would involve weight loss getting slower and slower until it eventually stops). Second, one hits target and begins upping one's calories until one finds where equilibrium lies. On very limited calories we're looking at option two rather than option one, but surely that's true of a great many people? Thoughts, anyone?
Hi Brid. If you read in the maintainers' forum, Option 2 seems to be what pretty much all of them do. I think Option 1 is possible only if you opt to eat at your maintenance weight from day one and are willing to be incredibly patient at the end of the journey to lose the last few pounds, and that does not seem likely. I think when Option 1 happens, that's often when people reach a plateau and have to make some adjustments to start losing again. But the theory goes that your metabolism gets used to very low calorie, so you you will have to continue to eat very low calorie to maintain when you eventually get to goal weight. I don't know if that theory's accurate, but it's certainly prevalent.
I'm not sure I agree with his conclusion of NEAT being heavily reduced because I don't know how you account for which came first (slow down in NEAT or weight gain because said person has lower NEAT to begin with) but it is clear that the metabolic slow down factor is not significant.
Opinions aside, you run a very real risk of under-nourishing your body and that's what people are concerned about and why they always warn people of VLCDs. We can site many studies and all give our opinions of the outcomes of those studies but you have to decide if this risk is worth the reward of rapid loss. Keep in mind if this isn't a medically supervised plan, you're flying without the safety net of the diagnostic test a doc can provide to check organ function and likely won't know if it's causing you problems until you KNOW you're having problems.
You will have to make the choice but please consider the risk. There is no point in weight loss if your health suffers.
