Diets

[amicky]

Assuming you're properly hydrated before a dive...
Does being on a diet make you more succeptible to DCI?

I understood that in most diets you lose liquids first, then fats. On that basis...

Also, would any particular diet be better/worse than any other?

[Nigel Coote]

Assuming you're properly hydrated before a dive...
Does being on a diet make you more succeptible to DCI?

I understood that in most diets you lose liquids first, then fats. On that basis...

Also, would any particular diet be better/worse than any other?

I lost 4 stone with Slimming World with no problems with DCI.
I must admit ive put some of it back on, but its a diet I found I could eat eat and eat more on.
Good Luck.

[Steve Walker]

I understood that in most diets you lose liquids first, then fats. On that basis...

I think this is talking about the relative long term affects rather than your hydration levels on a given day

Also, would any particular diet be better/worse than any other?

I don't believe there would be any solid scientific data to back up any claims made on behalf of any particular diet as there simply isn't the body of empirical research being carried out on DCI to support/refute claims or hypotheses. Also, diets and related "health" topics are prone to outrageous and unsubstantiated claims as to their purported benefits, most of which don't stand up to proper scientific examination (the USA are cracking down on this issue, don't know about here in the UK though)

THe link I've given will take tyou to a site which deals with understanding nutrition-related findings/claims but in plain everyday language.

If you are (i) excercising regularly & (ii) following a sensible (ie not a fad) diet, then your body should be adapting to burn fat. Hypothetically speaking, this might actually be beneficial as fat metabolism should liberate water as a consequence but I don't know if that would be a factor in DCI prevention. But as you're aware of correct pre-dive hydration I'm sure you'll be fine
HTH
Steve

[amicky]

Oops - sorry wasn't a query regarding relative merits of diets / which one I should go on...

Was a "medical" query regarding "do diets (in general) make you more succeptible to DCI?"

[Nigel Hewitt]

Oops - sorry wasn't a query regarding relative merits of diets / which one I should go on...

Was a "medical" query regarding "do diets (in general) make you more succeptible to DCI?"

OK. Blind guess from a physicist whose only medical training was typing his wife's Podiatric Surgury Final Project. (I know things about feet that you don't ever want to hear.)

Being on a diet will lessen the amount of clutter in the blood stream and enhance the blood transport of gases. This means reduced time constants on a Buhlmann model for physical tissues but since we model for a whole range of half-times and choose the worst case that is really no change. However what is a problem is time non-linearity ie: where gases come out of a tissue slower than they go in and the usual cause of that is termerature. If you're blood sugar is down your body will accept colder peripheries (foot problem!) rather than normal as it will hold onto the fuel. Hence the gas that passed into nice warm fingers/toes/skin comes out slower from the cold f/t/s and may hit the critical tension level sooner.

So I would guess there is a slight increase in risk but it could well be below the day by day variation of an individual and the result so the diet in a terms of overall body health will probably more than pay you back in terms of total risk over the year.

But don't listen to me. I do ballistics for a living not blood chemistry.

nigelh

[Steve Walker]

Oops - sorry wasn't a query regarding relative merits of diets / which one I should go on...

Was a "medical" query regarding "do diets (in general) make you more succeptible to DCI?"

Sorry, didn't realise my post read like unsolicited dietary advice. In brief, there's little enough hard scientific data on DCI generally and none as far as I am aware which deals specifically with diets and DCI, so in response to your question: "do diets (in general) make you more succeptible to DCI?" The answer would be "Does not compute, insufficient data available"

[steve swift]

of :=:=Was a "medical" query regarding "do diets (in general) make you more succeptible to DCI?"

Caveat: I am a physical educationalist, not a Dr or biochemist:

I read the question as based on the thinking that in any low calorie situation (ie a diet,)the body will utilise glycogen as a source of energy before it will begin to metabolise fats. Glycogen binds with water when it is stored, and as the body utilises the glycogen stores, the water is liberated. This loss of water is said to constitute most of the rapid weight loss in the initial stages of low calorie diets.

If dehydration can increase the chances of DCI, could this loss of water do the same?

Back to the Drs and biochemists....

Steve

[Nigel Hewitt]

I read the question as based on the thinking that in any low calorie situation (ie a diet,)the body will utilise glycogen as a source of energy before it will begin to metabolise fats. Glycogen binds with water when it is stored, and as the body utilises the glycogen stores, the water is liberated. This loss of water is said to constitute most of the rapid weight loss in the initial stages of low calorie diets.

If dehydration can increase the chances of DCI, could this loss of water do the same?

I would say that water bound into Glygogen cannot be involved in inert gas transport so it is no change. I think the problem with dehydration is that at first it comes straight out the blood volume. This means that below some critical level inert gas transport drops and what went in on a short time constant comes out on a slow one so the assumptions in the tables that the body is at least roughly consistant fall down.

nigelH

[Steve Walker]

:=I read the question as based on the thinking that in any low calorie situation (ie a diet,)the body will utilise glycogen as a source of energy before it will begin to metabolise fats. Glycogen binds with water when it is stored, and as the body utilises the glycogen stores, the water is liberated. This loss of water is said to constitute most of the rapid weight loss in the initial stages of low calorie diets.
:=
:=If dehydration can increase the chances of DCI, could this loss of water do the same?

I would say that water bound into Glygogen cannot be involved in inert gas transport so it is no change. I think the problem with dehydration is that at first it comes straight out the blood volume. This means that below some critical level inert gas transport drops and what went in on a short time constant comes out on a slow one so the assumptions in the tables that the body is at least roughly consistant fall down.

nigelH

Additionally, though depending on how the dieter follows their programme, if it is a "crash diet" the body will actually save the fat stores and metabolise protein, mostly I understand from skeletal muscle tissue, and as we all know fatty tissues off-gas more slowly, so I suppose you could argue that a crash diet would be inadvisable in diving terms. Though this is purely theoretical and conjectural.