Sunday, April 27, 2014

The Real Food Guidelines and Saturated Fat in the Media

Things are happening in New Zealand 

The Real Food Guidelines 

Grant Schofield and several others have put together a document called the Real Food Guidelines to argue against the Dietary Guidelines.  You can view their analysis here 

In it they argue against guidelines to 

  • To be a healthy weight, balance your intake of food and drinks with your activity levels
  • Eat plenty of breads and cereals, preferably wholegrain
  • Prepare foods or choose pre-prepared foods, drinks and snacks: (1) with minimal added fat, especially saturated fat (and therefore also the emphasis on low fat dairy and lean meats); (2) that are low in salt; if using salt, choose iodised salt 

It’s great to see a variety of diet dogma being challenged at once (SFA >> CVD, fat >> obesity, salt >> hypertension, grains are nutrient rich, grain fibre is healthy).  Regarding the first point, my take away wasn’t that they are CICO deniers but rather think weight loss is more sustainable if calories aren’t restricted (and instead are spontaneously reduced) 

I left some comments here and have some further thoughts: (1) it’s good they used RCTs to justify LCHF for weight loss (and CHD risk factors) rather than the CIH of obesity (which I don’t believe in, here’s why); (2) the traditional Chinese cooking of using the whole animal could be argued more strongly for with the nutrient density of organ meats, the importance of glycine and sustainability, but I appreciate that it’s a minor point) 

Saturated Fat's Health Benefits under Scrutiny 

This is followed by a segment on New Zealand TV (3rd Degree) called Saturated fat's health benefits under scrutiny.  I thought it was fairly well done.  It was presented in a kind of debate style and was fairly balanced in screen time and questioning towards the experts (unlike Catalyst).  Basically the show was Grant Schofield and Caryn Zinn arguing that LCHF is better for weight loss and SFA doesn’t cause CHD, against Jim Mann and Rod Jackson arguing the standard SFA >> LDL-C >> CHD 

Some thoughts: 

  • Caryn’s trolley looked quite nice and surely couldn’t be too objectionable
  • I can understand the emphasis on berries as they have a health halo as superfoods, but IMO it sounds kind of elitist and faddy (don’t take it personally, just something that’s been bugging me for a while).  Berries are very expensive per kg or per calorie, while other fruit like apples, oranges and bananas are quite cheap
  • Referring to fat is nutrient dense is generally incorrect because fat only contains fat soluble nutrients (the vitamins, CoQ10, CLA, LCO3), and perhaps choline, so added fat is generally nutrient poor per calorie.  High fat whole foods can be nutrient dense, such as avocado, fatty meat, brain, eggs, milk and soybeans, but it’s easy to see in the case of meat and milk that fat reduces nutrient density per calorie
  • There have been some comments about the excessive amount of butter used.  I don’t know if it’s just there for shock value.  (If you eat > 60-70% fat you probably do need to do things like that) 

I was disappointed with the opposition 

"There is no evidence whatsoever that a high intake of saturated fat is good. And in fact there is a lot of evidence that a high intake of saturated fat is bad”
"There are a very limited number of people that understand the literature who would actually say we’ve got it wrong in terms of saturated fat, and what is more not only is there a general consensus about that…” 

Perhaps it’s just that there are a limited number of people who understand the literature.  The meta-analyses used by the mainstream against SFA suggest there’s no benefit in replacing SFA with MUFA or carbs, and that there’s only a benefit in reducing SFA if it’s replaced with PUFA.  So if SFA is bad (or poisonous), then MUFA and carbs must be bad (or poisonous) too.  On closer inspection, I learned three main things about the trials that replaced SFA with PUFA (see The DHH Part 1-4 and the individual trials) 

  • The high PUFA group always received advice to reduce TFA and/or junk food.  Often the high PUFA group also received advice to increase whole plant foods, fish/omega 3 and/or lose weight, etc and/or there were other differences between the groups (cardiotoxic medicine, smoking and cooking methods for example).  Therefore there were many differences between the SFA and PUFA groups that put the PUFA group at an advantage
  • The trials that were better controlled (where the only confounding variable was advice to reduce TFA and/or junk food) showed either no difference or harm in replacing SFA with PUFA, with the only benefit coming from a reduction in ‘probable’ + ‘possible’ events in a non-blinded trial
  • The trials that showed consistent benefits (reductions in CHD events, CHD mortality and total mortality) were the most poorly controlled 

The show may lead people to: (1) make false dichotomies of SFA being either unhealthy or healthy and couldn’t possibly just be ‘ok’; (2) think that we just need to compromise, that the middle ground is the truth and we should focus on the things they agree on (like junk food and sugar).  But at least this gets the debate out there 

* Someone may object to Rod Jackson saying we can isolate SFA.  I agree with him, and that it would be done sufficiently in a margarine vs. butter study (for example).  Even though there would be differences besides SFA and PUFA it would have greater external validity.  It’s too bad that the trials did such a poor job of controlling for things in general 

** Jim Mann: "There is one thing I would never concede, and that is that it's okay to have as much saturated fat as you'd like,".  Enough said, unless ‘as much as you’d like’ means overeating, in which case overeating anything is generally bad 

*** "Frankly I think this is the biggest red herring to be polite – garbage to be a bit less polite," says Professor Mann. "Your ancestors and mine, wherever they came from, were jolly lucky if they lived to be 40”.  HG lifespan is grossly underestimated.  Most HG’s who make it to 15 live to 45 and 45 year old HGs can expect to live another ~20-25 years [1] 

**** Jim Mann: "They need to get on and produce that evidence, and I would argue producing that evidence before they try to persuade the world that they’ve got the answer."  I agree, dietary recommendations should be held to that standard.  It’s a shame they aren’t

3 comments:

  1. Great review Steve!
    Around the butter question, re-reading Stock and Yudkin's 1970 low carb weightloss paper http://ajcn.nutrition.org/content/23/7/948.full.pdf
    Gave me an insight:
    on a standard high-carb diet there's a lot of butter (or its poor equivalent) in cakes and spread on bread. It may be that the "known" butter consumed by LCHF dieters is only compensating for this "lost" butter. In the Stock and Yudkin paper, the 11 dieters didn't even do that; the controls ate slightly more fat as well as much more carbohydrate.
    I agree about the berries, although frozen berries can be cheap; there's work still to be done adapting and pricing LCHF for those on a budget. I guess in induction phase (in Atkins terms) we want the lowest-carb fruit there is.

    ReplyDelete
    Replies
    1. Thanks George

      I don't think 2 weeks is enough time to know what they would be eating during weight maintenance as the weight loss would reduce calorie intake (I'm assuming they lost weight, but I don't think it mentions weight)

      I can understand why people emphasise berries on a LC or keto diet - you want the carbs you eat to be as delicious and nutritious as possible (most berries except strawberries have similar carbs/g as other fruit (just Googled)). That comment was more directed to people who promote Paleo as Paleo has an image problem of being expensive and elitist and I think a good way to start changing that is to say 'fruit' instead of 'berries'

      Delete
    2. In 1950's-60's low carb diets, fruit is fruit. Berries seem to come in with Dr Atkin's Age Defying Diet in the 80's, where he gives fruit a score by comparing ORAC scores with carb content. So it's about maximising antioxidants, especially such pleiotropic benefits of berry anthocyanins that might seem to be indicated by research.

      I found this in Low Carbohydrate Nutrition and Metabolism (Westman et al. 2007)
      Because an instruction only to restrict carbohydrate intake could theoretically create a diet containing any level of daily energy intake from protein and fat, confusion exists among researchers and the lay public about what constitutes an LCD. As early as 1980, LaRosa found that subjects following an LCD do not necessarily replace the carbohydrate with either protein or fat, but that they, rather, reduce starch and sugar intake (9). Under such conditions, even though the absolute amounts of fat and protein do not increase, the percentage of fat and protein will increase. Recent research reviewed below has determined that the reduction in calorie intake is a result of appetite and hunger reduction. In this way, LCDs are also low-calorie diets that include an increase in the percentage of calories from fat and protein but not necessarily an increase in absolute amounts of fat and protein.
      http://ajcn.nutrition.org/content/86/2/276.full

      Delete