Fat controversy hits headlines
You should tuck into some cheese, cut out all sugar, and forget about counting calories to lose weight, a controversial report has claimed. Is it true?
The report from some members of the National Obesity Forum has received criticism from health and nutrition experts, but received widespread media coverage.
It is worth firstly bearing in mind that this is a report, it is not a critical analysis of all the relevant evidence, and it does not include any assessment of the methodological quality of the studies that it mentions. Moreover, the authors are not named and it does not appear to have been peer-reviewed.
Dr Mike Knapton, Associate Medical Director at the BHF, said: “This report is full of ideas and opinion but it does not offer the robust and comprehensive review of evidence that would be required for the BHF, as the UK’s largest heart research charity, to take it seriously.”
Other experts have accused the report of “cherry-picking” the evidence it uses, for example, highlighting one trial suggesting high dairy intake reduced the risk of obesity, but ignoring a systematic review of 29 trials that concluded that increasing dairy intake did not reduce the risk of weight gain.
Dr Knapton said: “This country’s obesity epidemic is not caused by poor dietary guidelines; the problem is that we are not meeting them.”
The claim that eating fat doesn't make you fat is absurd
Claim 1: You should eat more fat
The report also states that “eating a diet rich in full-fat dairy – such as cheese, milk and yoghurt – can actually lower the chance of obesity.” This could be misleading, as 100g of cheddar cheese is around 400 calories, so increasing your cheese intake could mean that you have a lot more calories to burn in order to avoid putting on weight.
Professor Tom Sanders, Emeritus Professor of Nutrition and Dietetics at King's College London, said: “The claim that eating fat doesn't make you fat is absurd and plain wrong… If you eat a lot of fat, you will get fat.”
Dr Gunter Kuhnle, a nutritional scientist at the University of Reading, warned: “The document presents as fact what has not even achieved consensus in the scientific community, such as the role of fat and carbohydrates... By doing so, it could confuse consumers, and also make discussions within the scientific community and the general public more difficult. In the long term, this is likely to have an adverse effect on public health, as it leads to ‘advice fatigue’.”
Diets that are high in saturated fat have been shown to increase cholesterol. High cholesterol is linked to an increased risk of cardiovascular disease, hence why current recommendations emphasise the importance of reducing this.
All fruit and many vegetables (carrots, beetroot, onions, parsnips, sweet potatoes) contain sugar
Claim 2: We should eat “zero sugar”
The report says that sugar has no role in a healthy diet, but balanced diets with inevitably contain sugar from fruit and vegetables.
Prof Tom Sanders, Emeritus Professor of Nutrition and Dietetics at King’s College London, explained: “All fruit and many vegetables (carrots, beetroot, onions, parsnips, sweet potatoes) contain sugar about 5-10% by weight and milk contains 4-5% sugar. Following the 5-a-day advice for fruit and vegetables and drinking half a pint of milk/day provides about 45 g of sugar.”
Claim 3: We should “avoid industrial vegetable oils”
It’s unclear what the authors mean by the term “industrial vegetable oil”, as “most vegetable oils are refined to remove free fatty acids and gums that give rancid flavours,” Professor Sanders explains. “Refining also makes oils more stable for storage and for cooking,” he says. However as vegetable oils are high calorie, it’s wise to limit your intake of them.
Claim 4: We should stop counting calories
People gain weight when calorie intake is more than the calories burned, so calorie labelling is useful for consumers, and suggesting that everyone should stop monitoring their calories is irresponsible.
Professor Sanders says: “This report muddles quality and quantity because you can still eat too much of a ‘good diet’. Obesity is caused by eating too much – not just by eating unhealthy foods.”
Focusing on single foods, nutrients or risk factors is short-sighted
Claim 5: You can’t outrun a bad diet
Exercise alone will not lead to weight loss, however regular exercise – such as brisk walking daily – can prevent weight gain. There is some truth in this claim, though, in that taking regular exercise doesn't mean that we don't need to follow the nutrition guidelines.
Claim 6: Don’t eat processed food that claims to lower cholesterol
The term ‘processed food’ is ambiguous as any food preparation could be called processing. Professor Sanders says: “The term ‘proven to lower cholesterol’ is only used on some high fibre breakfast cereals (usually oat or barley based cereals) and in spreads containing plant phytosterols. Phytosterols lower LDL cholesterol by 8-10% and the safety of phytosterols for food was carefully evaluated under the Novel Foods Directive.”
Moreover, any claims that a certain food or drink lowers cholesterol is subject to the EU Health Claims Regulation, and has to be carefully evaluated by the European Food Safety Authority.
Dr Knapton said: “Heart disease is a multifactorial condition with a range of risk factors and any dietary and lifestyle advice worth noting should consider the overall impact that our diet and lifestyle has on our health. Focusing on single foods, nutrients or risk factors is short-sighted.”
The media coverage
The story received widespread coverage, including in The Telegraph, Metro, Daily Mail, The Guardian and the BBC.
It was also on the front page of the Daily Express, with a headline ‘Eat more fat to stay healthy: food experts at war over new advice on patients diet’ and the Daily Mirror, with the headline ‘Low-fat diet bad for your health’.
It is difficult to criticise the coverage as misleading, since it accurately represents the bold claims that the report makes. However, a lot of the coverage presents the reports claims as facts, for example the Metro’s headline ‘A diet high in fat actually isn’t that bad for you – and could fight obesity’.
Similarly, if readers just looked at the front page of the Mirror, rather than reading the full story, it reads ‘experts say cutting back on meat, eggs and dairy is a disastrous mistake’. The front page doesn’t explain that the report has not been peer-reviewed, is arguably not properly evidenced, and has received wide criticism; where the coverage mentions this it’s often far down in the story.
An exception to this was the story on the BBC News website which used the headline ‘Public Health England: Advice to eat more fat “irresponsible”’ and focused on Public Health England’s view of the report. Also, we do not know who specifically has written the report, apart from Dr Aseem Malhotra, so coverage that uses the term ‘experts say’ could be wrong.