2015-2020 Edition of the Dietary Guidelines for Americans
I thank Nina Teicholz for the key facts in this section.
The Dietary Guidelines, that were never scientific in nature, are presented in 2015, with only very minor changes, but now they are considered to be "evidence-based." Chair of the committee, Barbara Millen says, "that the evidence base has never been stronger." Something that I don't doubt, given the lack of any scientific evidence behind the original recommendations.
Asked specific questions about the lack of research on saturated fats and low-carbohydrate diets she said, "We didn't feel any need to do them. We didn't do them. That's why you have an expert committee, to bring expertise."
There seems to be a strong reluctance to depart from the existing recommendations. They always opt for the status quo, and it seems they choose not to examine research that might force them to re-examine that position. They are resolute about two key concepts: a calorie is a calorie, and all foods are part of a "balanced diet." They are willing to restrict sugar, hard fats and red meat, they seem to have a preference towards vegetarian diets. I'll briefly take up three points.
Eating patterns that promote overall health:
The goal of the Dietary Guidelines is for individuals throughout all stages of the lifespan to have eating patterns that promote overall health and help prevent chronic disease. Yet these guidelines vary only in minor ways from the dietary guidelines used in the well funded, very meticulously controlled and well executed Women's Health Initiative. That was the largest nutritional trial in history, involving nearly 49,000 women, and running for seven years. The study found that the diet had no significant advantage for weight loss, diabetes, heart disease or cancer of any kind. The committee chose not to consider the evidence of the WHI trial. (Is this a case of excluding what you choose not to know? Both Nina Teicholz and Dr Noakes seem to believe so.)
Of course every member of the committee is well aware of the Women's Health Initiative and even though they don't want to "include it" they have responded to it. The key conclusion of the Women's Health Initiative was that the recommended diet had none of the health benefits researchers expected to find. So the new guidelines have a difference. There are now THREE recommended diets, the Healthy U.S.-Style Pattern, the Healthy Mediterranean-Style Pattern, and the Healthy Vegetarian Pattern. Numerous studies have shown that the Mediterranean diet was superior to the old Standard American Diet. The Healthy U.S.-Style Pattern, recommends less sugar and less red meat than the previous SAD diet.
Saturated fats are called empty calories:
The new guidelines take a slightly stronger stance against sugar, describing it as empty calories. However, dietary saturated fat is also restricted and given the same "empty calories" label. This seems strange. It's suggested that there are commercial reasons why the stance against "hard fats" is maintained given a large body of evidence that demonstrates the opposite. Hard fats are mostly consumed as part of real food, fish, meat, offal, eggs and dairy food. These are the most nutritious foods available to us. There were 12 small studies available to the committee in the National Evidence Library, none of which support the committees view, that saturated fats are harmful to the heart. These studies were not considered.
The committee did not do any significant research into low-carbohydrate diets, despite the fact the such diets have become very popular. The committee says it could only find limited evidence, and little of it based on US populations. Chair, Barbara Millen said, "Many popular diets don't have evidence." But that's not the case. Since the year 2000, there have been 9 pilot studies, 11 case studies, 19 observational studies and at least 74 randomised controlled trials, 32 of which ran for three months of longer. Almost all of them were US based. So what do we see here? Is this another case of choosing not to see the evidence?
To briefly summarize what they didn't look at: There is evidence that low-carbohydrate diets are better than other dietary patterns for controlling type 2 diabetes. Two meta-analysises have concluded that a moderate to strict low-carbohydrate diet is highly effective in achieving weight loss, and in improving most heart disease risk factors, at least in the short therm.
New Much Stronger Exercise Recommendations:
I found this really surprising. Gone is the recommendation of twenty minutes walking each day for older people.
"If you are 65 years of age or older, are generally fit, and have no limiting health conditions you can follow the guidelines below:"
They begin this way: "Jogging 2 hours and 30 minutes at moderate intensity every week." (That means very brisk walking or running.) AND weight training muscle-strengthening activities on 2 or more days each week that work all major muscle groups. (Legs, hips, back, abdomen, chest, shoulders and arms.)
But they say more time equals more health benefits.
"Older adults should increase their activity to: jogging 5 hours each week, plus the 2 hours of more of weight training muscle-strengthening activities" as previously recommended.
So clearly, they know the diet's wrong, but they believe they can fix it with exercise.