By, Nina TeicholzInvestigative science journalist. Author
Presentation to
Canadian Meat Council
• “This book should be read by every nutrition professional…” • –American Journal of Clinical Nutrition
• “Impressive . . This book shook me. . . Teicholz has done a remarkable job” • —The BMJ (British Medical Journal)
• “A Best Book of 2014”• —The Wall Street Journal , Economist, Mother Jones, Times of London, BBC
A very confusing diet world out there!
• From Berkeley, CA
• From Berkeley…to New York city
• A low-fat eating vegetarian for 20+ years
I came to this without any preconceptions
High school, 145 lbs
• I receive no industry support of any kind—not for my book or my subsequent research.
Current Diet Recommendations
USDAPyramid
MediterraneanDiet
VITAL SIGNS
Risks: More Red Meat, More MortalityBy NICHOLAS BAKALARPublished: March 12, 2012
The Bad News About Red Meat
How I got into this…
We need to explain this:
What I’m going to talk about today
• What’s gone wrong with official nutrition policy
• How it went wrong
• Why this is a story more about politics than science (Though we’ll talk about the science, too)
• Bring you up to date on the latest science that you may not know about.
How it all started
19001955
Saturated Fat/Cholesterol(in the diet)
Elevated cholesterol in the blood Heart Attack
The Diet Heart Hypothesis
Ancel Keys
1961, The American Heart Association
First advice anywhere in the world to limit saturated fats and cholesterol
in order to prevent heart disease
Saturated fats (butter, lard, tallow)
Why this idea made little sense given the data at the time
Unsaturated vegetable oils
1961:Ancel Keys was “Mr. Cholesterol”
The most influential nutrition scientist of the 20th century
But what was the evidence at the time??
The Seven Countries Study
Studying the islanders on Crete….who were long-lived
….during Lent
“The Greek Orthodox fast is a strict one and means abstaining from all foods of animal origin, including fish, cheese, eggs and butter”
—Contemporary Observer
Trying to prove the diet-heart hypothesis with randomized controlled clinical trials
(the “gold standard”)
• There were actually a large number of government-funded, randomized, controlled clinical trials…..on hard endpoints
•
• On altogether some 75,655 men and women, in experiments lasting 1 to 12 years
• Most in in-patient settings; therefore highly controlled.
• RESULTS: No effect of saturated fats on cardiovascular mortality or total mortality
L.A. Veterans Trial—risk of cancer
Dea
ths
from
can
cer
The Politics of Nutrition Science
Selection Bias: the Minnesota Coronary Survey
Conclusion:
“For the entire study population, no differences between the treatment and control groups were observed for cardiovascular events, cardiovascular deaths, or total mortality."
US Dietary Goals
Isn’t it all our fault?Americans don’t follow the Dietary Guidelines faithfully enough
Americans exercise too little
Major macronutrient shift in US1965-2011
0
10
20
30
40
50
60
1965 1971 2011
Carbsupby30+%
Fatdownby25%
Saturatedfatdownby17%
Source:Cohenet.al.,Nutrition,2015,volume31,Issue5,727-732
“…physical activity is generally insufficient by itself to bring about clinically significant weight loss…a dietary intervention is usually needed”
U.S. Govt. Physical Activity Guidelines Advisory Committee Report, 2008
“sedentary behavior cannot be shown to lead to obesity.” Report by the US Govt. Dietary Guidelines Advisory Committee, 2015
Conclusion: You can’t exercise your way out of a bad diet
On EXERCISE….
Maybe it’s not our fault after all…Maybe its’ the fault of the Food Guide itself…??What does the science now say?
#1:Saturated Fats Do Not Cause CVD Death
Now>15meta-analysesandsystematicreviewslooking at:linkbetweensaturatedfatsandheartdisease.
Takentogether,theseconcludethat:
• SaturatedfatsareNOTASSOCIATEDWITH heartdisease
• SaturatedfatshaveNOEFFECTONcardiovascularmortality
Thefollowing recommendationsdonotincludeathresholdorlimitforsaturatedfat
August 2015
The surprising benefits of saturated fats
1. The only food known to raise your HDL
2. These are stable fats that do not oxidize when heated
3. They are natural, in whole foods
#2:Eating Cholesterol does not Worsen Blood Cholesterol
Ancel Keys’Diet-Heart Hypothesis
SaturatedFat/Dietary
cholesterol
Raisedcholesterol
(intheblood)HeartAttack
#3The low-fat diet doesn’t work
This diet has been tested in NIH-funded, randomized controlled clinical trials (gold standard), including the Women’s Health Initiative and others.
On >65,000 men and women (mainly women)
Conclusions:• The low-fat diet cannot be shown to be effective at fighting obesity, diabetes, heart disease, or any kind of cancer.
• The 2015 Dietary Guidelines committee wrote that the low-fat diet is associated with “decreasing HDL and increasing triglycerides,” which are both signs of an increasing risk of heart disease.
• That is why there is no longer any official “low fat” diet recommendation.
#4Fat Does Not Make you Fat
SwedishGovernmentReport2014
#5:Fat Does Not Cause Cancer
•World Cancer Report 2007: •No association between fat of any kind and cancer.
Path to Diabetes (consistent exposure to insulin over time)
What is the evidence supporting this theory?
•More than 74 Randomized controlled trials •Virtually all of these studies are on Western populations•At least 32 trials of low-carb diets have lasted six months or longer •Three lasted 2 years (the gold standard) to see any adverse side effects•These trials establish that low-carb diets are safe•These trials also establish that low-carb diets are effective for fighting obesity, diabetes, and heart disease (improves nearly all CVD risk factors)
“I Ate Butter and my Pants Fell Off”
Yet isn’t red meat unhealthy?
Red meat originally condemned for its saturated fat content.
Yet link between saturated fat and heart disease unraveling
Red meat now condemned based on weak epidemiological evidence
The available randomized controlled trials contradict
the idea that red meat is bad for health.
1.Polyp Prevention Trial: Test of a diet low in fat and animal foods for the prevention of cancer• NIH funded, on 2,079 people for 4 years. • Intervention group significantly decreased red meat and processed meats, replacing them instead with chicken
• Conclusion: • researchers found no effect of this intervention, at the end of the trial or at the eight-year follow up, on the
recurrence of colorectal cancer.
2. Women’s Health Initiative: Test of a diet low in fat and animal foods for the prevention of cancer• NIH funded, on nearly 49,000 women for 8 years• Women on the low-fat diet reduced red meat by 20% compared to controls, a statistically significant amount;
• Conclusion: • Researchers found no effect on any of type of cancer. (Also no effect on heart disease, diabetes, or obesity.
3. Meta-analysis of all RCTs: • Conclusion:
Why is this science not reflected in our Dietary Guidelines?
•Although the DGAs have for decades recommended avoiding saturated fats and cholesterol to prevent heart disease, no DGA committee has ever directly reviewed the enormous body of rigorous (government-funded, randomized controlled trials) evidence, testing more than 25,000 people, on this hypothesis.
• The DGAC recommended reducing red and processed meats yet did not conduct an analysis of the scientific literature on this subject.
Take-home Messages
• There is no rigorous evidence to show that red meat is bad for health in any way;
• Meat has been erroneously condemned for its saturated fat content; it turns out that these fats do not cause heart disease.
• You can enjoy eating these delicious foods again.
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