Food Fight: Late 70s Low-Fat Diet Science Recs Faulty. -Or Were They?

A new meta-analysis review of the 70s-80s low-fat-diet recommendations of The McGovern Report is out.

And the controversial Zoe Harcombe’s team concludes the science behind the report was so undercooked and incomplete as to be false.

So because of that, they suggest the floodgates on high-fat diets have been opened, and it’s: F*** The Fettuccine, Full Butter Ahead! -Or so it would seem…

 
What many of the posts on this report don’t tell you is this:

Several doctors have reviewed the team’s conclusions and have disagreements and rebuttals of their own.

 
Professor Christine Williams:

Calls the conclusions, “Misguided and potentially dangerous”. And goes on to say:

1) That there have been Clear Improvements in people’s cholesterol levels, regardless.

2) The Type of Trials examined are only good for Drug testing and little else.

3) The relationship of Saturated Fat in Diet and Cholesterol in the Blood was so well & broadly-studied at the time, doctors even came up with an accurate Equation to predict one from the other.

4) As people’s Total Fat-Intake has gone down, the part of it that’s Saturated Fat has gone down even more, and that’s good.

5) From the few studies available, when people increase their general fat-intake, their Saturated Fat intake tends to go up, too.

And even just a 3% increase in that, Does increase cholesterol in the blood.

 
Dr Nita Forouhi also criticizes the early work, noting that:

1) The original evaluation of low-fat on cholesterol was not well-done & that the benefits of getting rid of saturated-fats were still worth it.

2) The 6 original studies were not great, but you also cannot use them to recommend the opposite. And this becomes clearer when you don’t cherry-pick and look at more evidence from that time & since.

3) The original studies only reported who died, not heart-attack victims who survived. -That is still valuable info for saying which approach is better.


Prof. Kevin McConway points out:

There was more evidence at the time than just the 6 studies that Harcombe criticizes.

And more evidence since.

 
Prof. Richard Mithen notes:

The trials Harcombe criticizes aren’t even used for diet, because it’s much more complex than testing a drug.


Prof. Simon Capewell:

Criticizes her implications that Saturated Fats are not to be worried-about, especially since at least 8 other large studies have established their link to Blood-Cholesterol and ends his crit with this quote:

“[…] the greatest crime is embodied within the penultimate sentence in the Discussion: “questioning the alleged relationship between saturated fat and coronary heart disease”. Why say “alleged”? It is surely monstrous to suggest that the scientific evidence linking sat fats and coronary heart disease has not increased hugely since 1983. OMG!”


Prof. Tom Sanders goes a bit further:

“This report summarises six small trials conducted more than 30 years ago, which were of short duration and lacking sufficient statistical power to show any effect on mortality rates.

the authors are wrong to suggest that advice to decrease total and saturated fat should not have been introduced. Their conclusion fails to take into account the totality of the evidence.

it was not feasible to conduct sufficiently large dietary trials

It was well established that high blood cholesterol and being overweight or obese played a major role in causing atherosclerosis.

Anyway it seems to have turned out okay, as cardiovascular disease rates have fallen in the UK and other countries

[and finally:] The advice did not encourage replacing fat with sugar or refined carbohydrates. It advised selecting lean cuts of meat or poultry and fish in place of red meat, removing fat from meat before consumption, choosing reduced fat milk and using vegetables oils.”

 
Dr. Iain Johnson says:

“The authors of this review highlight the negative results of relatively short-term intervention trials used to test dietary strategies for the treatment of patients with existing heart disease.

–They then use these findings to criticise long-term dietary guidelines developed for the very different purpose of minimising the risk of heart disease in healthy populations.

[…] this paper does not, in my opinion, add anything important to that process.”


SO: There you are. You get one big splashy crit that seems to make a recommendation against common-sense, but then several other experts chime in and show you where the house-of-cards is wrong.

 
*Now where Harcombe’s team is NOT wrong is:

People Have eaten more carbs since then.

They’ve eaten more Fast-Carbs since then.

AND obesity has risen.

Not only that, but she’s right that Fast-Carbs raise your insulin, make you fat, & raise a different kind of fat-in-blood, called Tryglycerides that might be more dangerous than just Cholesterol.


But what both sides seem to ignore is The Law of Unintended Consequences.

When people reduce fat, what do they replace it with? -Cheap Carbs.

When people increase fat, what comes along with that? -Saturated Fat? -Which leads to… Cardio-Disease.


So, In Conclusion: Next time you read about some Brandy-New critique or change that goes against the old rules that seemed to help in at-least ~some kinds of ways,

Don’t Jump On The Bandwagon Immediately.

Wait & see if it’s just someone cherry-picking in order to make a big-statement.

(-Even if it’s that new ~technicality about Cholesterol in food.) [link]


-That and one last bit: Biases.

Back in the Red Meat Is Killing You post, I think we found out that Zoe Harcombe seems very pro Red-Meat & Dairy. -At least that’s the way her writing sounded at the time.

And then a counterpoint to that is: Stanley Hazen’s idea that there might be an Amino Acid in Red Meat that increases Heart Disease.

 
PPS:

Just remember: the real specifics of nutritional biochemistry & gut microbes, esp. where they relate to ultimate cardio health, Have Not been cracked yet.

-Otherwise there would be very specific diet recs out there, everybody would be taking custom probiotics tailored to their own personal bellies & nobody would get heart-disease ever again.


Photo Credits:
“The 1970s-1972 fashion 14 (13)”, “the 1970s-1975 western style suit-14(15)”, by Flickr user april-mo
“1970s – Powerline VS646 Electric Sprayer”, by Flickr user TempusVolat
“The 1970s- 1974 Jours de France ad for Leleu fabrics”, by Flickr user april-mo


Links:
• Source(s): TheVerge | SMJ-The Experts Respond
• More Coverage: Telegraph.co.uk | Reuters | Harvard-Low carbohydrate diets are better
• Source Study: BMJOpenHeart-Evidence from randomised controlled trials did not support the introduction of dietary fat guidelines in 1977 and 1983: a systematic review and meta-analysis