Atkins Diet Effect on Air Consumption

[flip1]

I started the Atkin's diet phase 1 (<20 gms carb/day) 3 days prior to a couple of days diving with my son. He typically ends a dive with ~300psi more than I do but this time it was more in the range of 1500psi (he is 15 & 140# and I am 43 and 250#).

I suspected that possibly the state of ketosis (fat burning) I was in was effecting my oxygen metabolism. Several non-diving sites describe physiological mechanisms of:

1. 
   [/list=1]
   1. CO2 accumulation in tissues due to a depletion of bicarbonate ions
   2. O2 can not be effectively utilized when there is a disturbance in the acid-base relationship in the tissues
   3. Osmotic interchange between arterial blood & tissues is impacted and O2 is carried away by venous blood w/o being used.
      [/list=1]
      
      This physiological response seems to fit my more rapid air use on this dive trip.
      
      Has the effect of a low carb diet (ketosis) ever been studied for divers? I have seen some ancedotal posts on the message boards that it is good for endurance but would appreciate a more technical discussion.
      
      b.t.w. I don't plan to try it again, as we both want some more bottom time.
      
      Thanks, Flip1

 

[buff]

I don't know what the Atkins diet does for air consumption but I can tell you that it doubled my father-in-laws cholesterol and put him at such a dangerous level that his cardiologist told him to quit the diet immediately.

The brains only source of energy is glucose. Why would you ever starve your brain of anything?

Look at all the marathon runners, Tour de France bike riders, triathletes. They all eat lots of carbs and are very lean. They don't eat junk in between their meals and don't eat a lot of fat-that's the American diet and that's why we are so fat-and getting fatter.

Eat a good diet just like your doctor tells you to. It's not flashy or trendy but it works.

 

[Lost Yooper]

Everyone I know who is on the Atkins diet has lost a lot of weight and dropped their cholesterol levels and triglycerides. The one diver I know who is on it hasn't had a change in air consumption, but his energy levels have sky rocketed.

It's a proven diet that's actually been around for a fairly long time. If it doesn't work for you, get off it. We're not all the same when it comes to all that stuff.

Good luck.

Mike

 

[devjr]

My guess is that the effect that you are describing is only temporary. After a few days, a high protein, high fat/ low calorie diet should cause your metabolism to slow to a new set point and reduce air consumption. The carnitine content of a high protein diet should give the dieter a feeling of strength and well being. A high sugar diet, eg potatoes, pasta, juice, granola, honey, temporarily boosts metabolism, causes sweating and stimulates the heart, and because of insulin rush, fails to assuage hunger causing the dieter to cheat. The body will attempt to convert some of these carbs to fat unless you are exercising strenuously. Athletes feel that the temporary increase in glycogen storage helps short term performance. Sedentary individuals may experience mood swings due to stimulation of the brain, etc.

All weight reduction diets are high fat by definition. After all, the body is obtaining a third of its calories from burning body fat alone. Therefore, ketosis can be a concern in some individuals. I don't know what practical effect this would have on air consumption. I do know of freedivers who reported noticable increases in breath hold time when losing weight on high protein, low carb diets. The fat content of these diets appeared to be moderate.

Some random thoughts: perhaps some individuals would show higher cholesterol on a high fat diet. I don't know. A high protein diet can be hard on the liver. There is a causitive link between high fat intake and diabetes. This may sound problematical, and the theory is very complicated, but I'm convinced. However, at the same time, loss of body fat is thought to be beneficial in this regard.

 

[Rick Murchison]

The modus operendi of the Atkins diet is to throw your body into ketosis. This is not a normal state of affairs. I do not recommend diving while in this state.
Rick
PS I don't recommend you go out in public, either. Those who've really done this diet or been around those who have know what I mean.

 

[flip1]

Thanks for everyones comments so far, looks like the true mechanism may not be known.

Rick, I agree with your comment about not diving while in a state of ketosis. It is a lesson I learned and others may benefit from also. Your PS comment is also accurate but especially true while excercising.

Flip1

 

[devjr]

Flip, I've been meaning to ask you for references to the effects you mentioned. It sounds more like ketone acidosis than ketosis. These are quite different.

As far as I know, the Inuit who consume a high fat diet do not show adverse health consequences. I'm not very familiar with the Atkins diet but would like to learn more.

 

[flip1]

Devjr, you are correct that I the mechanisms I described in the original post are for acidosis. This particular reference was http://www.nutrimed.com/ACID.HTM. Not a primary reference and they don't site their source.

The Miller-Keane Medical Dictionary definitition of Ketosis is accumulation in the blood and tissues of large quantities of the KETONE BODIES: beta-hydroxybutyric acid, acetoacetic acid, and acetone. Because the first two are acids, this results in metabolic "acidosis". Thus, the condition is often referred to as ketoacidosis.

A referreed journal article in Journal of Naturopateic Medicine entitled "Anorectic and Mood-Altering Effects of Ketosis During Ketogenic Diets " has an interesting discussion on ketones and oxygen consumption. The following is the relevant paragraph.

"The blood receives ketone bodies produced by the liver and carries them to the heart, skeletal muscles and brain to be utilized as oxidative substrates for fuel. Ketone bodies account for only 10% of the oxygen consumed after an overnight fast. However, this figure may increase to between 30% and 90% of oxygen consumption after 48 hours of restricted carbohydrate intake."

The reference given for the 30 to 90% O2 consumption, appears to be for rabbits (we have been compared to worse) and is shown below, if anyone has an old copy of the Journal of Bio Chemistry:

"Wick AN, Drury DR. The effect of concentration on the rate of utilization of beta hydroxybutyric acid by the rabbit. J Bio Chem 1941;138:129-34

For the MDs and biomedical types, I have spent the last 20 years in semiconductors (i.e., chip making) and it has been 25 years since high school biology.

Flip1

 

[Rick Murchison]

Originally posted by devjr
Flip, I've been meaning to ask you for references to the effects you mentioned. It sounds more like ketone acidosis than ketosis. These are quite different.

As far as I know, the Inuit who consume a high fat diet do not show adverse health consequences. I'm not very familiar with the Atkins diet but would like to learn more.

Here's an article in lay language that explains how a low carb diet (the Atkins diet, for example) induces ketosis:
http://www.nutrition.cornell.edu/nutriquest/ketosis.html
Rick