Can 500 calories/day support an active, healthy adult?

I got to chatting with this gentleman in the steamroom at my gym the other day after he came in and I had asked him what he was doing (he was shifting sort of rapidly side-to-side with his arms straight down to his sides). After he told me he was ‘working on this’-pointing to his love-handle area-:dubious: he tells me that he has been dieting for the past few months.

He says he’s lost nearly 60 lbs and his doctor has him on a 500-calorie a day diet. I shook my head, looking down at my protein shaker; I had more than that right in there. :eek: I can’t comprehend how a doctor can recommend such a starvation diet? Surely, in addition to the metabolic disaster such a diet would inflict on the person, wouldn’t it be prone to exacerbate some medical conditions (none specifically jump to mind but I pose the question to more qualified minds)?

I mean, he did say he’s lost weight and he did seem to be happy with what he’d been doing but if he’s telling the truth (and he very well could be eating more than he even realizes) I can’t comprehend how someone could live in a healthy way for months on end on 500 calories a day, with no supplements. And he said the doctor didn’t even put specifications or restrictions on what type of calories made up that 500, he could eat any food he wanted; just not more than 500 calories of it in a day.

I know there are some doctors here, does any of this ring as true or sensible to you? Would a doctor put someone (albeit fairly obese) on a caloric-restrictive diet to the extent of just 500 a day? And consider this is with a regular schedule of working out with weights and cardio. *

*Not sure if this belongs here or in GQ. Mods feel free to move accordingly.

I wonder if he’s only eating 500 calories of actual food (anything he wants), but having more calories from supplemental sources like shakes that give him the nutrients a person needs to function day to day. The lowest my doctor told me I should ever go was 1200/day.

Nope. No supps, no shakes, no calories, period over 500.

Due to a serious medical problem back in early 2007 I did, in fact, subsist on around 500 calories a day for a few weeks because I simply physically couldn’t eat more than that or it wouldn’t stay down. I find it hard to imagine a normal human being could limit himself to just that quantity no matter what it was composed of, I almost think complete fasting would be easier. Personally, I found the week I went entirely without food (in a hospital, under medical supervision) psychologically easier than being ravenously hungry and limited to such small quantities.

No restrictions or recommendations on what that 500 calories is composed of? That’s… bizarre. If it’s all protein you’re looking at ketosis which could get quite ugly. If it’s all carbs then you can get the body self-cannibalizing muscle and (if it goes on long enough) even vital organs to scavenge needed protein.

Assuming the OP’s report of the guy’s statements are correct, that just doesn’t make sense. More likely, he’s misinterpreted what his doc has said or something, or he’s just distorting/lying about the whole business.

I’ve been on that diet, actually. 500 calories of nutrient-enhanced shakes. You COULD have more, but the baseline was the 500 calories and of course you’d probably lose the most weight that way.

It worked, yes. I couldn’t stand drinking shakes and eating, effectively, MREs.

Missed that bit. In that case, I have a hard time believing a doctor put him on a diet like that. When I was doing the 1200 calorie thing, I couldn’t do any exercise or I’d just feel faint all day. I didn’t stick with that very long even though it was doctor directed. I can’t imagine exercising to a net intake of zero calories or negative calories.

Yes - but not for long. I did it once for about two weeks, in combination with a cyclical ketogenic diet and strength training three times a week. It was definitely a crash diet, and unless there were some highly unusual circumstances for this guy, I doubt a doctor would have advised it.

This is what I am thinking as well. I think just watching his weird penguin-shuffle in the steam room was enough to convince me this guy didn’t know the difference between ice cream and ice water.

even if he is as represented - no it cant, hence the 60 lb loss.

Sounds like the hCG (human chorionic gonadotropin) diet garbage.

Can you lose weight on a crash diet? Yep. Is it healthy? Probably not. Will you gain back most of the weight when you go off the very low calorie restriction? Almost certainly. If you try to maintain a very low calorie intake for too long, it will have a definite long-term effect on your health.

Actually, Broomstick, if someone were silly enough to go on such a diet, I’d recommend most of their calories come from protein to offset as much muscle loss as possible.

Ketosis is not dangerous. It’s a normal metabolic pathway when carbohydrates are in short supply, even if that’s only temporary due either to exercise or intake. Ketoacidosis is what happens when you’re diabetic or alcoholic and the feedback mechanisms that keep ketone production in check don’t work properly. It bears roughly the same relationship to ketosis that a controlled campfire does to a wildfire.

Transient ketosis seems to be, in fact, neuroprotective. A long-term ketogenic diet has been used for the treatment of epilepsy, with very good success. There are promising findings for low-carb diets in the treatment of type 1 and especially type 2 diabetes too.

Maybe his doctor is more like Dr. Nick than Dr. Hibbert. My mom is fond of saying that there have to be doctors that graduated at the BOTTOM of the class.

I’ve been recording every morsel of food I eat for several weeks. My target range is between between 1600 and 1800. One day last week I’d gotten to about 4:00pm with only about 685 calories eaten. I didn’t have the opportunity to eat anything else at work, or right after because I had an appointment. By the time that ended I was jittery and uncomfortable and ready to go to the Burger King drive through and order one of each.

He was in the steam room following his workout, no? There has to be a detail not disclosed (by steam room guy, not the OP)…

^ That was my experience, too, but then, I was starting at a normal weight and plunging to underweight. Maybe someone seriously overweight would have more energy as they would have more bodyfat to burn, but I’m inclined to doubt this.

what do they call the student that graduates last in his class in Med School?


The calorie range isn’t unbelievable that a doctor would advise it, but I think most reputable doctors would not advise 500 calories of “any food you please.”

For extremely obese people, physicians have put people on “Very Low Calorie Diet Plans” which can range from 500-800 calories per day. However, these people eat nothing but specially formulated shake type products which insure you get a certain amount of potassium, sodium, protein, fat and all the key vitamins, trace minerals, EFA/EAAs essential to life.

I can’t imagine a doctor would just tell a patient to go on 500 calories of whatever they want, as I could imagine serious health consequences if an uninformed dieter just say, ate 500 calories in Reese Cup’s each day for a long period of time.

Now, physician supervised VLCD plans with those special formulated shakes–extremely obese people have been kept on those plans for months and months. However they are supposed to be getting monitored regularly by a physician for any signs of trouble, and again, these diets are not considered ideal unless you have an obese person whose obesity has got to the point where doing something that otherwise is a bit unhealthy (consume way too few calories) is seen as beneficial compared to the harm being caused by the obesity itself.

Here is a WebMD article on physician supervised low calorie diets.

I find 1200 calories really easy. I’ll often only eat that when not in a diet, though I have done it for a month or two at a time deliberately.

500, though - that would be very hard indeed.

When I was in the Army and overweight the Army Doctor put me on a 1000 calorie a day diet. Every two weeks he dropped it by 100 calories until I hit 700 and at that point I lost a pound, yep one. After another two weeks I woke up in the hospital, I had passed out at work and had been getting fluids for about a day and a half. Shit storm hit my CO and the Doctor for treating me this way. After a huge series of tests I was given a 56 pound waiver for muscle mass and sent on my way with documents to tell the CO to leave me alone.

500 calories? I would probably have died.

Real MREs have about 2500 calories.

I recently did two weeks of around 600-700 calories per day of a high protein, minimum carbs diet and it was OK for about a week but it went down hill pretty fast at the end of the second week. I could barely think enough to complete simple everyday tasks. I did no extra exercising at that time except regular walking. I have plenty of fat reserves.

I would say the gym guy is mistaken about his calories.

I can not see the benefit of any crash diet unless it’s a “you are going to die in two weeks if you don’t lose weight now” situation. There are no shortcuts to sustainable healthy living and weight loss.