Dr Robert Atkins viewed ketosis as a "metabolic advantage" to
weight loss. I'm of normal weight
with a Body Mass Index just under 25 (over 25 is a worry), and the advantage of
ketosis for me is the stability and ease of control it confers on my blood
sugar, the protection from hypoglycemia it affords (because almost all tissues
can burn ketones as well as glucose), and the fact it
improves my "hypoglycemic awareness" - I know when I'm
"low."
Briefly, the body naturally turns to fat for fuel when carbohydrate isn't
available. When a lot of fat is
burned, some of the fat fragments - ketones - get
excreted to preserve the body's acid-base balance (because ketones
are acid), and this is called "ketosis." The excreted ketones
have about 5 calories per gram, and since you can excrete quite a lot of ketones, Dr Atkins' dubbed this a "metabolic
advantage."
Let's look at ketosis in more
detail:
- When my blood sugar drops
after a low-carbohydrate meal, the hormone glucagon
is released which causes triglycerides to be released
from my body's store of fat.
Glucagon also causes the liver to break
the triglycerides into glycerol and free fatty acids ...
- The glycerol part of the
triglyceride provides about 7% of the fat calories as glucose, but this is
not enough to maintain my blood sugar level. The balance comes from the
breakdown of protein from the food I've eaten.
- Meanwhile, the free fatty
acids are cut into two- and four-carbon fragments called ketones or ketone
bodies. Ketones
are normally present in the bloodstream, but when their concentration
exceeds 70 mg/dl, they start to appear in the urine - this is
"ketosis."
- Ketone
bodies are the preferred fuel of the
heart, adrenal cortex, skeletal musculature and various parts of the
brain; these tissues actually prefer to burn ketones,
which conserves blood sugar (from refs in Eades
& Eades, Protein Power, Bantam,
1998, p. 149)
- Excess ketones
are excreted in the breath, stool and urine, mostly in the urine. Test strips passed through the
urine stream reveal their concentration. I use Ketodiastix
which also show the level of sugar in the urine because I want to
distinguish between normal ketosis and diabetic ketoacidosis
- this happens when a diabetic takes too little insulin and the resulting
combination of very high blood sugar plus very high ketones
can cause coma and death.
- Trace to moderate ketones a few hours after a meal means I'm burning my
fat reserves and/or recently-eaten fat for energy between meals in a normal
process of metabolism. I'm
excreting the ketones which are in excess of my
energy requirements to maintain a physiological acid/base balance (ketones are acidic).
- Since I'm getting rid of
unburned fragments of fat during this ketosis, I'm only getting maybe 5
calories per gram from the fat I eat.
I can therefore eat more fat without putting on weight, or I can
lose weight without having to burn it off through muscular exertion. Fat
provides 3500 calories per pound, so losing a pound means a lot of
exercise. If I want to lose
weight, I cut back on carbos; and if I wanted to
gain weight - fat chance! - the experience of my
lifetime suggests that all I have to do eat more carbs.
- When the KetoDiastix
indicate "Large ketones", I generally
feel fatigued, headachy and sometimes nauseated, so Dr Atkins metabolic
advantage isn’t very useful for me. Acetone is a ketone,
so my breath has that "hungry person" smell when the test strips
show “Large ketones”.
- Ketosis on liquid protein
diets - low-fat, high-protein diets - caused deaths from heart
failure because protein from the heart muscle was used for blood
sugar. I actually have to make
an effort to eat enough fat to make this way of eating work for me! I have lost only fat, not muscle
mass, but I'm sure that if I ate too little fat or too few calories while in
ketosis, I would lose muscle.
You just simply can’t do a low-fat, low-carb
diet, the calories have got to come from
somewhere!
- Ketosis masks appetite in the sense that I don't crave
food. I'm hungry when my blood
sugar is low and I need food.
This may sound like the most natural thing in the world, but for an
insulin-dependent diabetic, it’s like winning the lottery. I have my blood sugar, my weight
and my appetite under control.
It's like a miracle. As a bonus, ketosis has been shown to protect against insulin reactions. I
hope to live on the cusp of ketosis for the rest of my days.
How does one enter ketosis? I cut out all refined carbohydrate and used
smaller and smaller quantities of low-glycemic index carbs like creamed spinach, steamed asparagus and broccoli
until the Ketodiastix indicated ketones. Then I kept my carb
intake near this critical percentage, which is about 5-10% of calories for
me. It took a violent shift in attitude
to eat enough fat to make this work. The payoff in terms of diabetic control
and mood stability are simply incredible. The years of searching for an answer
to the frustrations of insulin dependence have not been wasted.
Those Unfamiliar with Ketosis Fear
that it is Dangerous
"Liquid Protein" diets like the Cambridge
diet introduced after publication of The Last Chance Diet (1976)
killed at least fifty people whose hearts failed through fibrillation. This very low calorie, low fat diet
caused people to lose muscle mass everywhere, including the heart which
eventually gave up. The Food and
Drug Administration warned the medical community about the danger of this kind
of diet which gave ketosis a bad name.
The nutritionists and popular diet advisors listened. Jane Brody said ketones
are toxic. Stuart Berger bashed
them in How To Be Your Own Nutritionist. Ann
Louise Gittleman writes in Your Body Knows Best:
Without some carbohydrates to maintain blood sugar levels
and fuel the system, ketone bodies - fatty substances
generated from the breakdown of stored fats or triglycerides - are soon formed
in the blood. Ketone bodies mask your appetite even though your brain
demands glucose. The result is
ketosis: headaches, light-headedness, and mental fatigue. Eventually, [on a low fat diet] your
body will begin to convert protein from your muscles into blood sugar. You lose weight, but it is from muscle
mass, not from fat. (Pocket Books, 1997)
This is absolute crap. None of
it’s true in my experience on a low carbohydrate diet without caloric
restriction. I'd bet a buck that
she hasn’t personally experienced moderate ketosis on a low carbohydrate
diet without caloric restriction. It is well established that ketosis is part
of the normal metabolism, and that ketones can supply
up to 90% of energy, with the brain fulfilling about 2/3rds of its energy
requirement with ketones and the rest with glucose
(Barnes RH et al, J Biol Chem,
1939;131:413-23).
I feel well nourished. My mood
is more stable. My appetite is
linked more tightly to my blood sugar level, so I don't have the
"hypoglycemic unawareness" which sends most insulin-dependent
diabetics to the emergency room sooner or later. I reach for a snack, but only when I
need one.