Fat and sweets or processed meats — what is really safe to eat?

Nutritionists expiate saturated fat, the dietary villain of the past, but unite against sugar

Food health scares and dietary controversies continue to erupt in the news. Last year, for instance, the World Health Organisation’s cancer agency told us that processed meat is a cancer hazard; in the UK, Public Health England and the House of Commons health committee threw their weight behind a sugar tax on sweet drinks to curb the obesity epidemic; and New York City forced fast food joints to put a sinister symbol of a saltshaker inside a black triangle beside high-salt items on their menus.

The news has not been all bad. Several studies now suggest that one of the worst dietary villains of the past few decades, saturated fat from dairy products and meat, may not harm the heart as much as we have been led to believe.

Two sweeping reviews of existing studies, using the “meta-analysis” technique, found little or no benefit from cutting down on saturated fats.

One carried out by the Cochrane collaboration (an international organisation producing independent medical evidence) pulled together the results of 15 clinical trials in which a total of 59,000 participants were divided at random into groups consuming different amounts of saturated fat for a period of at least two years. Reducing fat had no effect on mortality, though it slightly cut the number of non-fatal heart attacks and strokes.

The other review, a meta-analysis by researchers at Canadian universities, focused on 73 “observational studies”, which are larger and easier to carry out than clinical trials but regarded as less authoritative in scientific circles. It too concluded that people eating more saturated fat were no more likely to suffer heart disease, stroke or type-2 diabetes, or indeed to die prematurely of any cause.

But the world’s biggest dietary health story of 2015 was the declaration in October by the International Agency for Research on Cancer that processed meat is carcinogenic while unprocessed cooked red meat is “probably carcinogenic”. That unleashed a predictable storm of protest, with the North American Meat Institute calling the report “dramatic and alarmist over-reach”. In a memorable attack on the agency, Barry Carpenter, Nami president, said: “Only one substance, a chemical in yoga pants, has been declared by IARC not to cause cancer.”

That left neutral scientists to put the report into context. “The WHO’s decision means that there is sufficient evidence that processed meat consumption causes cancer,” said Gunter Kuhnle, a food nutrition scientist at the University of Reading. “It does not mean, as purported by many stories in the media, that eating bacon is as bad as smoking. This is a dangerous oversimplification as processed meat can be part of a healthy lifestyle; smoking can’t.”

Kevin McConway, professor of applied statistics at the Open University, puts it like this: Of 100 people who never smoke, one will get lung cancer; of 100 smokers who get through a pack of cigarettes a day, more than 20 will get lung cancer. About 6 people in every 100 get bowel cancer; the figure rises to 7 in every 100 for those who eat two rashers of bacon a day over a lifetime.

After meat, sugar was the top ingredient in the year’s food health stories. The UK saw a succession of official reports calling for Britons to cut sugar intake by more than half for the sake of their health.

These said people should consume no more than 5 per cent of their daily calories as sugars. The previous official UK recommendation was 10 per cent, while actual sugar consumption is 12 per cent of an average adult’s and 15 per cent of a teenager’s calories.

A study published last week in The Lancet Diabetes and Endocrinology found that cutting the amount of sugar in fizzy drinks by 40 per cent over five years would prevent 1m adults becoming obese and 250,000 from developing diabetes.

One possible policy change, recommended by the British Medical Association and the Commons committee, is a tax on sugary drinks. Their sales have fallen by 12 per cent in Mexico where a 10 per cent tax was introduced two years ago, according to another study last week.

Industry bodies such as the Food and Drink Federation and the British Soft Drinks Association reject the swelling chorus of calls for such a levy, saying that sugar should not be “demonised” among the many factors combining to cause obesity.

Support for strong action against excessive sugar in manufactured food and drink is almost universal among medical experts, though not everyone thinks a tax is the right route. Richard Tiffin, director of Reading University’s Centre for Food Security, took part in a study suggesting that a 20 per cent tax on sugar-sweetened beverages would reduce obesity rates by between 1 and 2 per cent. “This is a small benefit for a tax that hits poor people hardest and could lead people to making other unhealthy choices in their weekly shop instead,” he says.

But Julian Hamilton-Shield, professor of diabetes and metabolic endocrinology at the University of Bristol, favours a tax. “No one can really doubt the harm sugar-containing drinks do to children: they rot their teeth and likely make them obese and at risk of later type-2 diabetes,” he says. “No one complains about tobacco taxation: sugar should be treated the same way.”

Besides raising the price of undesirable ingredients, another weapon to promote healthy eating is labelling.

The latest example is in New York City, which already requires calorie labels in restaurant chains. Last month it mandated the addition of a salt warning to anything on the menu that contains more than a teaspoon (2.3g) of sodium chloride.

So what is nutritionists’ current advice for confused consumers wanting to eat and drink more healthily? Few would dispute the prescription of a varied diet containing plenty of raw and cooked vegetables and fruit and some meat, fish and dairy products, lubricated with olive oil and washed down occasionally with a glass or two of wine or beer — but containing as little added sugar and salt as possible.

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