Chloe from the Paper Trail contacted me earlier this week to ask for my opinion on the US news Best Diets of 2015 article that was published earlier in January. To be honest, I’d not done more than take a cursory glance at the article as I didn’t expect to see anything earth shattering in terms of conclusions. So this was a good chance for me to have a look at the diets, the criteria, the experts and give my two cents worth. With Chloe’s blessing, I have re-posted here what I thought of the review.
Another year, another bashing of any diet that doesn’t conform to the dietary guidelines… the US News article outlining their Best Diets of 2015 held no surprises. Twenty-two experts weighed in on the review, with many top professors and clinicians from some of the world’s most prestigious institutions included. No one can argue their expertise and knowledge when it comes to critiquing the 35 contenders. But like anything, it’s not necessarily which diet comes out on top that’s important to consider, it’s more relevant to consider what the criteria is they are ranking the diets on. When you’re using the standard dietary guidelines as a framework, it comes as no surprise then that the DASH diet comes up as #1, whereas the Paleo diet shares the dubious last place position along with the Dukan Diet – for the second year in a row. As someone who uses a paleo template approach to diet, it could ruffle my feathers somewhat to see this. Does this mean you need to ditch your paleo diet for the more conventional healthy eating approach? Perhaps not.
Let’s look at what was reviewed. The criteria used included how easy the diet was to follow, its ability to produce short-term and long-term weight loss, its nutritional completeness, its safety and its potential for preventing and managing diabetes and heart disease. Panelists were also asked for their opinions on 35 different diets. I thought it would be useful to evaluate their ratings of both the top (DASH) and bottom (PALEO) and give my two cents worth.
The Dietary Approaches to Stopping Hypertension (DASH) diet is one of the few to cross over from the laboratory to population-based recommendations. The diet focuses on a high vegetable and fruit intake (9+), a high intake of low fat dairy products, a low overall fat and sodium intake. Along with the recommendation to reduce sodium (targeted in many public health campaigns for reducing blood pressure), these diet recommendations help increase other electrolytes (calcium, magnesium and potassium) responsible for blood pressure regulation.
The research has consistently shown the DASH diet is successful at reducing blood pressure. Those who are prescribed the DASH diet are coming from a standard Western diet and any improvement in food choice is going to improve health status. The increase in fruit and vegetables to such high (and awesome!) amounts will help crowd out the dinner plate and reduce the consumption of processed refined foods. This naturally reduces sodium intake (abundant in such foods) and sugar intake – also associated with increased blood pressure. While the glycemic load of the diet is particularly high – bran, orange juice, whole-wheat bread, bread roll, potato – potentially the inflammatory effects of a high GL diet which contribute to health risk are offset by the anti-inflammatory effects of both a low fat dairy intake, and the antioxidant effects of a higher vegetable intake. And, again – moving from a standard western diet to an eating plan like this will reduce inflammation regardless, thus reduce health risk.
It meets the recommendations for the macronutrients and ticks the box on the nutrients of concern: fibre, potassium, sodium and calcium – while falls short on the vitamin D. The expert panel has deemed it to be favourable for weight loss and reducing diabetes, and not too difficult to follow due to its protein and fibre content which increases satiety. All in all the DASH diet outplays all other dietary patterns.
So what is it about the paleo diet then that makes it rate so low compared to the DASH diet? It appears that the opinion trumps evidence in this “best diet” review, with a fairly dismissive overview of a dietary approach that focuses on vegetables, fruits, animal protein, nuts and seeds, while removing dairy, grains, legumes and refined fats and oils. This is evident just by looking at the section that illustrates how to apply the diet (the ‘dos and don’ts’ section). The reasoning of why to avoid dairy and grains ignores the evidence that exists illustrating the adverse relationship between western diet patterns and chronic disease and instead relies on the ‘because our ancestors didn’t do it, we should too.’ Few paleo advocates would use this as their main justification. More than anything, that is just a bit of lazy journalism. Further, the views around paleo have shifted since Cordain wrote his book on the paleo diet (from which the meal plan provided is based around). While certainly there are still people who steadfastly eschew dairy and legumes based on historical evidence, this is certainly not the case for most paleo advocates now who include them for people who can tolerate them.
The experts were particularly critical of the nutritional completeness of the diet – one saying that the risk of deficiency is “very real and one would need to take a multivitamin supplement.” Notwithstanding that a multivitamin was welcomed on the highly ranked low calorie Weight Watchers diet (and was not seen as a problem for the experts), that they equate the removal of food groups with the exclusion of nutrients is at best, ignorant. There is nothing in grains that can’t be provided for in a well-balanced paleo diet. If we compare the nutrients in the DASH diet with those provided by paleo, the main differences stem from the macronutrient contribution to energy. Had the experts been provided with Paul Jaminet’s or Chris Kresser’s paleo approach to diet, this would look quite different. While most paleo advocates recognise that low carbohydrate and paleo are not one and the same, popular media and those in ivory towers have yet to catch up. Earlier renditions certainly kept starch and fruit low but for those who are metabolically healthy and active, potatoes, kumara, seasonal fruit can all be included in a paleo diet. Further, if we compare these types of carbohydrates to grain-based varieties, it Further, evidence suggests these are more beneficial than grain-based carbohydrate making up the bulk of calories in other diets.
A closer inspection of fibre and micronutrients found a higher fibre, potassium, B12 and lower sodium content than pretty much any other diet. The experts point out that vitamin D is still likely to be low, yet intake is likely to be highest in a paleo diet with foods such as fatty fish, offal and eggs are some of the foods that are naturally highest in vitamin D in our food supply. Certainly the calcium content of the diet presented is lower than the recommendations. However, while calcium as a nutrient is certainly important for bone health –magnesium, potassium and vitamins A, D and K2 are all necessary for bone cell turnover, and all available in a paleo diet. There are plenty of cultures who don’t consume dairy products, yet have healthy bones. While the recommendation for calcium in New Zealand between 1000-1300mg, some suggest that 600-800mg is enough for bone health. Further, the bioavailability of calcium may be less than what is found in dairy products, it is better in people with optimal serum levels of vitamin D. As pointed out above, these levels are more likely to be found on a paleo diet. Finally, aside from my point above regarding the inclusion of dairy products in a paleo approach to eating, not all traditional paleo diets are as low in calcium as the one presented here. Dairy is indeed an excellent source of calcium, but not the ONLY source, with , foods such as sesame seeds, green vegetables, sardines and salmon (with bones in) containing considerable amounts of calcium.
The expert panel scored the paleo diet low with regards to weight loss and an individual’s ability to follow despite its high protein and high fibre content. Not only are these both known to improve satiety and weight loss outcomes, these were the reasons provided by the experts as to why the DASH was rated highly, yet ignored here for the paleo diet. Perplexing. There are few populations these days who are not yet westernised, though the data that does exist illustrate populations relatively free from the modern diseases of cancer, cardiovascular disease and diabetes that are so prevalent in the Western World. Studies do exist though (for example, see here and here), yet were largely ignored by the panel. Finally, if the panel embraced the paleo approach advocated by most people who promote it and include full fat dairy products for people who tolerate it, they would have more reason to rate it highly given the unique health benefits provided by dairy fat, including the provision of conjugated linoleic acid (shown to reduce cardiovascular risk) and butyric acid (shown to feed good gut bacteria).
This is the 5th edition of US News Best Diets, and until the paradigm under which these diets are evaluated changes, the results will not change. So back to my original question: does this mean you need to pop your Practical Paleo cookbook on Trade Me and pick up the latest version of the DASH diet? No. It means you need to stop taking the time to read these ridiculous New Year articles.