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Feeling Faint - Very Low Calorie Diet

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Hi All,

I have been put on a VLCD by my Dr, 800 calories a day.  I have been on it for a week, and I have just started to feel really faint and weak.  I was just wondering if anyone else has had this? My starting BMI was 41.  Before I started the diet I was having around 1500 calories a day.

I just checked my BSL (GMR, sugar level etc) and it was 6.8mml, which is fine, so that is not the cause.  I am trying to make an appointment to go back and see my Dr at the moment.

I really want to continue on this diet, it has been the first one that I have actually been able to stick to.  I am hoping that this is a just a faze that happens when starting a VLCD. I hate having to stop and hold the wall for 30 seconds every time I stand up.

Any advice, personal experience, etc, would be greatly appreciated.

Thank you


Edited Jun 23 2013 18:55 by coach_k
Reason: locked to prevent unnecessary zombie bumps
24 Replies (last)

Does it get any better? or is it something that will continue on as long as I am on the diet?

Your doctor's an ass. Why on Earth would he put you on such a diet? It seems stupid.

I don't get the dizzy spells from my diet, but I do get them quite often from my heart condition. I have chronically low blood pressure, so every time I stand up I feel light headed. What I've learned to do is to stand up while bending over so my torso is parallel to the floor, then while holding onto something slowly bringing my upper body upright. That helps a lot; it gives the blood time to come back up to the head.

Good luck!

People usually get dizzy spells when they are on such a low calorie diet. Talk to your doctor about it to see if it's not a serious medical condition. But otherwise, this is a pretty normal ordeal.

Why would anyone need to be on this kind of diet anyway? It seems like torture.

Its not torture, its actually a really easy diet to follow, and I have never been hungry since starting it, nor have I had any cravings for 'bad' foods. 

Back when I first started to lose the weight I was doing a VLCD on my own.  About 800-900 cals a day, and I nearly killed myself in the process.  Besides the dizzy spells I also had bouts of very low BP.  Be very careful here because your body really needs at least 1200 cals a day. 

If by doctor's orders you must remain on such low calories, make all of your food intake high protein, such as chicken breast. It may help some of the dizziness. Ditch all of the empty calorie foods.



Original Post by duke3522:

Back when I first started to lose the weight I was doing a VLCD on my own.  About 800-900 cals a day, and I nearly killed myself in the process.  Besides the dizzy spells I also had bouts of very low BP.  Be very careful here because your body really needs at least 1200 cals a day. 

 I agree. I tried to put myself on a vlcd years ago, and fainted in the middle of a store. I had such a difficult time regaining full consciousness I was taken out by ambulance.  My bp was low and potassium level dangerously low. I will never try that again!

Original Post by spankyraven:

Its not torture, its actually a really easy diet to follow, and I have never been hungry since starting it, nor have I had any cravings for 'bad' foods.

Well you're a stronger person than I am. Good luck!

I have just dropped from about 2000 cals per day to 1200 cals per day. I, too, have had a few (but minor) dizzy spells. I am not on a VLCD, but maybe my body thinks it is?!?! =)

If your insurance allows, please seek a second opinion. I have had my share of doctors who may not have been quacks, but were not really that great either. My pop's dr had him on a diuretic, and refused to administer a potassium test when he showed symptoms of low potassium! Just be careful. He/she may be a doctor, but you are the one who has to live with his/her mistakes.

Frankly, it sounds like your doctor is an idiot! If he's put you on a diet that low, you shouldn't be walking around at all - you should be in a hospital bed under constant medical supervision. The human body is NOT meant to function under a thousand calories a day (really 1200...) Less than a thousand calories is absolutely going to make you feel weak, sick, shaky, and dizzy because it's far too low to maintain your bloodsugar levels.

I'm not a Doctor and not qualified to critique this expert.

However I do KNOW that Doctors always instruct patients to contact them immediately if they suffer adverse effects from any course of treatment the Doctor has put them on.

Immediately call the Doctor and report your dizzy spells.  Then you will find out whether to proceed as is or whether you need to be re-evaluated.


Please check this link, as my mum seemingly was in a similar situation. It may help you in your quest. 4.html

me too the first time i was on my vlcd i kinda under ate .

a banana in the morning and a salad at night ....

I once fell asleep in the middle of talking while sitting in a comfy chair

this time in sticking to 1200

thats the lowest cals a female should have

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Hi spankyraven.  Are you limiting yourself to 800 calories a day or are you on a liquid fast?  It is almost impossible to get the necessary nutrients if you are using "real" food for the 800 calories. 

If your doctor just told you to do VLCD at 800 calories on your own with real food, then I think you need to change doctors.  Seriously.  If your doctor has you on something like Optifast 800, then you are mostly gettng what you need.  However, that is supposed to be a medically supervised plan - all VLCD should be medically supervised.  That means at a minimum you should have had full blood work before starting, and at intervals after starting. 

Are you monitoring your blood pressure at home?  One reason for feeling faint could be orthostatic BP changes - most likely from dehydration.  Your BP is really going to drop on a VLCD fast because you get almost no sodium and you are supposed to drink at least 3 quarts of water/day.  The water goes right through, taking your electrolytes with it.

One electrolyte that will affect your heart and can be symptomatic as in fainting is potassium.  That's one very important reason for the blood work before an during VLCD.  Low potassium can kill you.  I'm not being dramatic, and I'm not saying it to disparage VLCD.  Some diuretics also deplete potassium and doctors worry about that too for good reason.  Dehydrating someone with congestive heart failure is necessary, and their potassium level is always monitored and often supplemented.

I understand the benefits of a medically monitored VLCD.  I did it 20 years ago, and I started it again May 21.  20 years ago I did well for many years.  Over the past 2 years I've had some physical restriction, coupled with my emotional binge eating, and I've gained about 45 pounds.  Some of physical abilities are back - though now they are limited by my weight!  Anyway...

Another risk of VLCD to take seriously is gallstones.   VLCD medically monitored or not , and yoyo dieting, increase the risk of gallstones.  That is now very well documented in the medical literature.   Young, low weight ppl - the kind I think of as wanting to lose 10-15 lbs for the summer (I vaguely remember being one of those) develop gallstones from yoyo and VLCD.  It's not a matter of starting weight but of physiology and metabolism being affected.  That said, the risks of obesity may - not necessarily though - outweigh the risks of a medically monitored VLCD.

Finally, you will lose some muscle mass.  You will lose about 3 times as much fat in the beginning, but it is not possible to stay in sustained ketogenesis without losing some muscle mass.  If you are doing VLCD correctly, you will be in ketogenesis.  VLCD cannot be a longterm answer.

I developed a medical condition which necessitates - medically - rather quickly losing at least 20-25 pounds (real pounds, not water weight) and then more weight after that.  That is why I started Optifast 800 this time - "all or nothing", no choices, not really awful tasting.  I can do it.

However, from reading here and doing independent research on metabolism, VLCD, etc, I have decided that I am going to use the Optifast as a supplement rather than as a fast.  I have lost 4 pounds with the Optifast, and I lost another 1.5 with Optifast and some foods that I selected using the tools here.  I will not be going into ketogenesis, which is one of the magic tricks of fasting VLCD.  However, if everything I've read is correct, I will be losing about 2 pounds/week, which is about the Optifast rate after the first 3 weeks anyway.  To lose the 45 pounds I need time, and I don't want to be delayed by having to readjust my BMR from fasting. 

If you are actually being cared for by your doctor and are VLCD with full nutrients, then  I don't think you should be discouraged from continuing for a while.  It is a tremendous psychological boost to lose that first 30-40 pounds in a shorter rather than longer period.  As long as you prepare yourself for the real world of food, regaining some of the lost miracle weight, and understanding that to keep losing and avoid regaining what  VLCD made you lose, then it could be worth it.

But drink more water NOW and get to your doctor to have your potassium checked.  (You can be given potassium pills  if your labs are down.  If you ate food - a banana a day for a day or two would do it.)



May 29 2008 02:44
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I saw that you are a recent new member. Today is my first day.  I have the same BMI as you. 

Usually a banana with pb helps me get over the shakes from not eating though pb is too high fat and calorie laden.  Can you eat at least a banana?  You do need to get some protein. 

I think 800 cals is a bit low too.  I agree you need around 1200 well spaced out meals/snacks to keep your blood sugar on even keel. 

Thank you everyone for your help and advice.  I feel much better today, it may have been from something else, but I am seeing my Dr tomorrow anyway. 

Fromage, I am on the Optifast 800, and I did have all the blood work etc done before hand, and will see my GP every 2 weeks.  I have also been monitoring my BP, its a bid difficult because I have a manual sphygmamonoeter rather than an electric one, and my husband cannot hear the first and last korotkoff sound (listened to too much loud rock music, lol).  I also do regular BSL's as well, and they have all been well within the normal range. 

In no way are you being dramatic about low potassium, it is fatal! I had 2 episodes of low potassium due to Crohns, and both times went into very nasty arrhythmia's.  I am aware of the signs of it getting to low for me, fast heart rate, and muscle cramps.  It feels really awful, once my K got back to normal levels, I every muscle hurt like I had run a marathon, or been beaten all over.

As for the gallstones, that is why I am on this diet in the first place.  I will be having a lap chole to have it removed in 2 months, and want to get my weight down before having another anesthetic.

I will see what the Dr says tomorrow, and if everything is OK, I will probably continue on this for another 2 weeks.  Even a small amount of weight loss will be better for me during surgery and help with recovery.

Hi sbat, seeing as I am so new to CC I wont welcome you here, but its nice to hear of someone else with the same BMI.  What sort of diet are you following?

I cannot believe a Dr. would do that, for what reason. I don't believe anyone should eat less than 1200 a day.

800 Calories a day is ridiculous, adult women aren't supposed to have less than 1200 a day to maintain bodily functions. Watch out this may stress your heart and I'm pretty sure the fainting spells are from not having enough energy in your diet. Contact your doctor right away or get a new one. He doesn't sound like he knows what he's talking about. Please up it to 1000 just to be safe. You don't want your body to be starving itself and use up muscle mass that could also be why your fainting. Please be careful.

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