Transcript Atkins’ Diet – Does it REALLY Work?

Atkins’ Diet:
Does it REALLY Work?
Dr. Christine Simpson, MD FRCPC
General Internal Medicine
CHIP Director, Edmonton
Who?
• Dr. Atkins, cardiologist
• Sold 10 million copies of his book,
“Diet Revolution”, copyrighted 1973
• Other contemporaries:
– “The Zone”, by Sears
– “Protein Power”, by Eades
Why?
• Obesity epidemic began in the late 70’s
• Continual spiral upwards, despite the
low-fat dietary messages promoted
by the medical profession
• 60% Americans overweight (BMI >25),
30% are obese (BMI >30)
What?
• During the 1970’s, new concepts about fat
•
* primary nutritional evil
* especially saturated fat of meat & dairy
Atkins countered this by promising weight
loss while eating steak, eggs and butter to
our heart’s content BECAUSE:
* carbs cause obesity and heart disease
Atkins’ motto:
•FAT IS HARMLESS!!!
One follower says of the diet:
• Atkins allowed his readers to eat “truly luxurious
foods without limit,” as he put it, “lobster with
butter sauce, steak with bearnaise sauce…bacon
cheeseburgers,” but allowed no starches or
refined carbohydrates, which means no sugars
or anything made from flour. Atkins banned
even fruit juices, and permitted only a modicum
of vegetables, although the latter were
negotiable, as diet progressed.
Garry Taubes
How?
• High glycemic index foods (carbs that are
absorbed quickly) promote hyperglycemia
….an insulin surge…..then hypoglycemia
• This leads to hunger and MORE carbs
carvings; hence, increased caloric intake
• During the insulin surge, sugar is
transformed into FAT and muscle
The hypothesis:
• With a carb-depleted diet, there are NO
insulin surges
• When cellular glucose is depleted, fat and
muscle metabolism (break-down) begins
• This is the process called “ketosis”, which
is identical to that seen in starvation
Is there any scientific evidence?
• Up until 2002, virtually nothing
• Most “evidence” was anecdotal
• The best scientific evidence requires:
* a randomized, controlled trial
testing two groups of subjects:
a) Atkins diet versus
b) high carb diet
* Must look for benefits AND harm over time!
Two recent scientific studies:
• July 2002, American Journal of Medicine
• May 2003, New England Journal
of Medicine
• Funded by the National Institute of Health
The Details:
• 132 people, average weight 286 pounds
• 63 people, average weight 217 pounds
• Low carb (25-30 g/day, ~100-120 Cal)
• High carb (200-300 g/day, ~1200 Cal,
25% fat)
Followed for ONLY one year!
The Results:
• Low carb:
– 1) in 6 months, lost
13 pounds
- 2) in 6 months, lost
15 pounds;
regained 1/3
- HDL increased by 18%
-Trigs decreased by 28%
- No diff in LDL or BP
• High carb
– 1) in 6 months, lost
4 pounds
- 2) in 6 months, lost
7 pounds;
regained 1/5
- HDL increased by 3%
- Trigs increased by 1%
- No diff in LDL or BP
The Conclusion:
• A carb-depleted diet results in greater
weight loss in 6 months, and does not
cause significant harm to the lipid profile
(perhaps even a benefit?).
• ie. “A healthy, short-term method for
weight loss!”
?????????????????????????????????
•Does that really make
sense?
Studies are inherently flawed!
• Flawed in design and interpretation
• Very low sample size, very short-term
• 40% drop-out rate (same in both groups)
What we were NOT told:
• Carb-eaters caught up with weight loss
during the 2nd 6 months
• Diet compositions were actually NOT
drastically different:
* 41% (Atkins) fat versus 33%
* Dean Ornish says:
“they have compared two diets, neither of
which is very effective”
An even closer look:
• Most of the weight lost in the Atkins diet
group was due to a decreased total
amount of consumed calories!
• The initial weight loss is water, followed
by fat AND muscle; is ketosis dangerous?
• The lipid profile changes can not be
considered secondary to diet compositions
One more point:
• Ketosis theory and blood sugar/insulin
surge mechanism:
- NOT true when whole grains, legumes,
and high-fiber fruits and vegetables
are consumed
“Foods as grown, simply prepared!”
The REAL scientific conclusion:
• “longer and larger studies are required
to determine the long-term safety and efficacy
of low-carbohydrate, high-protein, high-fat
diets.”
• The debate continues, but the studies to date do
•
NOT prove superiority of an Atkins-style diet
over a high COMPLEX carbohydrate diet;
Rather, they simply re-emphasize that calorie
restriction aids in short-term weight loss.
Any volunteers for further studies?
•Questions?
•Comments?
Point 1:
•Save a quarter on your
food bill…
…and add 10 years to
your life!
Point 2:
•Don’t tell them it’s
healthy…
…tell them it’s cheap!