Dietary guidelines – confusing but useful

Governments around the world delight in offering their citizens detailed advice on what they should and should not eat. Some have food pyramids, some have perfect plates, and others have simple notes.

We like this simple Danish version:

The Danish 8 diet tips

  • Eat fruit and vegetables 6 pieces per day
  • Eat fish and fish products several times a week
  • Eat potatoes, rice, pasta and wholemeal bread every day
  • Limit the intake of sugar, particularly from soft drinks, confectionery and cakes
  • Eat less fat, particularly fats from meat and dairy products
  • Eat a varied diet and maintain a normal weight
  • Drink water when you are thirsty
  • Engage in physical activity at least 30 minutes a day

Many governments tell us that eating “5 a day” of fruit and vegetables is good for us – but what’s a portion? In the UK it could be a piece of medium-sized fruit or three serving spoons of cooked vegetables, or a glass of fruit juice (but NEVER potatoes). In Germany a portion is simply – but confusingly – between 80g and160g.

We’re told we should limit the amount of alcohol we drink – but how to know what’s safe? Agnieszka Kalinowski and Keith Humphreys of Stanford University in California found that national “standard drinks” units vary from 8g of alcohol in Iceland to 20g in Austria. Chile’s recommended daily maximum for men at 55g of alcohol is 5.5 times Sweden’s 10g maximum for women.

Guidelines aren’t the same as laws. And although there are some broad agreements around the world on what’s healthy, there are also some contradictions.

So what should we do?

The Food and Agriculture Organisation (FAO) of the United Nations says this: “Many dietary guidelines have things in common. For example, most promote variety and increased consumption of plant foods, especially vegetables and fruit, as well as reduced intake of solid fats, salt and sugar. But each set of dietary guidelines contains unique features to address the dietary needs of each country’s population.”

So how much of this advice is truly scientific, how much cultural, and how much due to lobbying or vested interests?

Here are some examples that might make you think twice:

  • In Greece they have separate recommendations on the amount to be consumed of solid fats and liquid oils. Is that because of evidence that oil is healthy but solid fat isn’t? Cultural bias towards locally grown olive oil? Or the result of lobbying by olive oil growers?
  • In the US, tight restrictions on fat content mean that some foods that are widely considered healthy cannot promote themselves as such – two notable cases being salmon and avocados. The same ruling allows foods that are low in fat but high in sugar, such as highly-sweetened breakfast cereals, jelly sweets that contain Vitamin C and low-fat (but high sugar) strawberry milk, to call themselves healthy. Science gone mad or the influence of the US corn syrup industry?
  • Worldwide there’s a growing call to avoid processed foods. Yet almost every government also recommends eating plenty of starchy foods, including bread. Surely bread is the original processed food? (although it can also contain high levels of salt, another restricted foodstuff).
  • In the UK recently a group called the National Obesity Forum called the government’s recommended low-fat diet “disastrous” for health. In a report which provoked heated debate amongst medical experts and nutritionists, they argued that whole foods and naturally high-fat healthy foods, including dairy products, are better for heart health and lowering obesity than the highly-processed low-fat, lite and cholesterol-lowering products promoted by the food industry.

More than 100 countries around the world have introduced food-based dietary guidelines since an International Conference on Nutrition in Rome in 1992. Yet obesity is growing faster than ever, and having guidelines seems to be making little difference.

Should we follow the guidelines?
There is one more thing to consider. There’s been very little research on two aspects of these guidelines: how many people observe them, and how effective they then are on these people’s health.

It seems likely that very few people actually stick rigidly to these ideas. If they’ve had any effect it’s probably been to drive awareness of the need to watch what we’re eating.

So should we dismiss something that has so much expert opinion behind it? Or should we actually give guidelines a chance?

Maybe we should all make time to review our own eating patterns. Take another look at those simple Danish tips. Think about the UN’s overview that we should all eat more variety, more plants, less solid fat, salt and sugar. Perhaps it’s worth a try?

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