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Updated 19 January 2016

New American Dietary Guidelines widely criticised

The American Dietary Guidelines are very influential and should be 'above suspicion'. DietDoc discusses the shortcomings of the latest set of Guidelines.

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Every five years, the US Department of Agriculture and the Health and Human Services (HHS) publish a new set of dietary guidelines for Americans. These guidelines are based on large volumes of scientific input and recommendations from a variety of sources.

Because the American Dietary Guidelines affect one in four meals eaten in the USA and also have a direct influence on the food intake in most western countries, the advice contained in the Guidelines should, like Caesar’s wife, “be above suspicion”.

Read: Food pyramid

The latest set of Dietary Guidelines for Americans which were published last week, and are intended to remain in place till 2020, have however, been widely criticised. 

What do the Guidelines recommend?

If we consider the broad outlines of the 2015-2020 Dietary Guidelines for Americans, they recommend that the US public should be eating:

  • A variety of fruits and vegetables
  • Grains of which 50% should be unprocessed (unsifted and unmilled)
  • Lean proteins, including lean meat, seafood, nuts
  • Oils rather than solid fats
  • Less than 10% of calories should be supplied by saturated fat and/or trans fats.
  • Less than 10% of calories should be supplied by sugar.
  • Sodium or salt intake should be less than 2,300 mg/day.
  • Alcohol consumption should be moderate – one drink a day for women and up to two drinks a day for men.

No cholesterol recommendations

For once, the Guidelines do not dwell on cholesterol intake or suggest a specific limit as in the past. This change is explained by the fact that the saturated fat intake is restricted to 10% of kilocalories a day, which should automatically restrict cholesterol intake.  

Expressing any dietary recommendation in terms of 10% of energy may mean be clear to dietitians, but I suspect that the majority of citizens will not fully understand this message.

Here is an example of what this actually means in terms of grams of saturated fat intake per day: If you are an adult consuming 2,000 kilocalories (8,400 kJ) per day, then 10% of that quantity of energy is 200 kcal (840 kJ) per day. Each gram of fat (any type – saturated, unsaturated etc.), supplies 9 kcal (37 kJ) of energy per gram, so divide 200 by 9 or 840 by 37 = 22g of saturated fat a day.

Read: Understanding the different kinds of fat in our diet

But most fats and fatty foods derived mainly from animal sources such as butter, cream, eggs, red meat, organ meats, full-cream milk and hard cheeses, and sometimes from plants (hard margarines, coconut oil and all products made from these fats), contain a mixture of saturated and unsaturated fats, so how do the members of the public know which foods they need to reduce to achieve the suggested goal of 22 g of saturated fat per day?

If you are enthusiastic you can check on food labels and add up your saturated fat intake every day, but broadly speaking you would need to reduce your intake of foods that contain saturated fat as listed above.

Read: Saturated fat may not cause heart disease

This type of a recommendation will certainly not go down well with Banters and Paleo Diet adherents!

Opposition to the 2015-2020 Dietary Guidelines for Americans

Long before these Dietary Guidelines were published, there was a great deal of debate about the suggested inclusions and exclusions during the public comment stage when 29 000 public comments were received by the Dietary Guidelines Advisory Committee (the committee) compared to only 2,000 in 2010.

According to Nina Teicholz, author of “The Big Fat Surprise”, writing in The BMJ (previously the British Medical Journal), some of the typical criticisms levelled at the new US Dietary Guidelines included the following:

  • The committee did not ask the Nutrition Evidence Library to carry out a formal review of the literature from the past 5 years to clarify their stance on saturated fats.
  • In addition the possible role of low carbohydrate diets in reducing the incidence of certain conditions (obesity, diabetes etc.) was not adequately clarified.
  • The committee appears to be advocating a shift away from animal-based foods to plant-based foods ever since 2010, but does not specify a ceiling for red meat intake.
  • The recommended diets (vegetarian, healthy-Mediterranean and healthy US-style diets) were also not researched and scrutinised adequately.                                            
  • Despite the fact that the intake of fruit juice should be reduced, the Guidelines equate a cup of 100% fruit juice with 1 cup of fruit.

Teicholz maintains, “The overall lack of sound science and proper methods in the 2015 report could be seen as reluctance to depart from existing dietary recommendations.” This reluctance to change which tends to create bias and favours maintenance of the status quo, may undermine the acceptance of the new Guidelines.

Teicholz also identifies a variety of potential conflicts of interest in role players who influenced the compilation of the new Guidelines. In her opinion, representatives of food industry are still exerting an influence on the American Dietary Guidelines.

How do the 2015-2020 Dietary Guidelines for Americans affect South Africa?

Considering that the majority of our population are not economically empowered to buy large quantities of foods derived from animals, a situation exacerbated by the severe drought we are facing, there are some positive aspects in the latest American Dietary Guidelines in relation to our country: Our national diet is being shifted to being “plant-based” because of ecological, climatic and economic factors, and we already have legislation to reduce salt intake.

Read: 10 tips to reduce your salt intake

Moves are also afoot to curb excessive alcohol and sugar consumption in South Africa and the emphasis in our revised Food-Based Dietary Guidelines (FBDG) is that we need to eat a variety of foods (if possible) that have low-fat, low-sodium, and low-sugar contents.

The South African (SA) FBDG promote the intake of vegetables, fruit, unsifted grains and legumes, low-fat milk and dairy products like cottage cheese, yoghurt or amazi/maas, lean meat, fish and eggs (when affordable), plant oils rich in mono- and poly unsaturated fatty acids, and clean, safe water. In addition, the public are encouraged to ‘Be active’ or engage in physical activity at work and during exercise to ensure health and normal weight.

I believe that the revised South African FBDG (2012) are suitable for the circumstances of our population and the challenges we face from ecological and climatic changes. We are, therefore, in a position to watch the roll-out of the American Dietary Guidelines knowing that we have adequate guidelines of our own.

It would, however, be welcome if the various mega-committees and organisations in the USA could come up with some substantiated proof regarding the role, if any, of high-fat, low-carbohydrate diets, and solve the latest dietary conundrums regarding red meat and processed meat, as well as alcohol intake exceeding one drink a week!

Read more:

Great new SA Food Guide

The new food rules

A healthy, low-fat slimming diet

References:

- Apple, S (2015) What the government’s dietary guidelines may get wrong. Published 10 Oct 2015 – what-the-dietary-guidelines-for-americans....

- NNW (2012).  Guide for health eating. Revised FBDG National Nutrition Week (NNW), 9-15 Oct 2012. http:www.nutritionweek.co.za.

- Teicholz N (2015). The scientific report guiding the US dietary guidelines: is it scientific? BMJ 2015;351:h4962; Time (2016). New dietary advice for Americans. Published on MWeb on 15 January 2016. 

Dr Ingrid van Heerden is a registered dietician and holds a doctoral degree in Nutrition and Biochemistry. She believes that "we are what we eat" and offers free nutrition and weight loss advice via her DietDoc service on Health24.com. Read more of her articles.

 
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