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    Which ‘science’ will Boris Johnson follow on obesity?

    22 June 2020

    The Prime Minister recently announced a new “battle of the bulge” after increasing amounts of evidence points to obesity as heightening the risks of complications from  Covid-19.

    Very soon after, the usual suspects surfaced. Not happy with the current tax on sugar, PETA are calling for an additional tax on fat and on meat. Not to be outdone, the British Obesity and Metabolic Surgery Society waded in, extolling the benefits of surgery.

    One group wants to starve us, and the other wants to operate on us. The surgeons at least have high-quality, scientific evidence to support their claims and a soothing bedside manner. I don’t doubt the noble intentions on both sides, but before calling for a diet of coconut water and grass souffle, perhaps we need to look into the underlying science. After all, the rationale for the “sugar tax” was the deleterious effect of ultra-processed foods.

    This tax of course does not apply to unprocessed carbohydrates like fruits and vegetables, whose higher intake is associated with a lower risk of death from heart disease.

    The same cannot be said of whole grains; they are so “essential to health” apparently that there is no scientific evidence to commend them.

    Eggs, poultry, meat and dairy are rich sources of protein, required for healthy bones, muscles, teeth and tissues. Evidence suggests that an egg a day is not associated overall with increased risk of heart disease and given that the cholesterol in eggs has no effect on blood cholesterol levels, it is high time this demonised food was rehabilitated.

    More than two servings a week of poultry in a recent paper have been associated with a higher risk of cardiovascular disease. This sounds damning until you realise that the study population were more likely to be smokers, have diabetes, have a higher BMI and consume a lower quality diet, thus suggesting that they already had major risk factors for heart disease than a healthy population. In absolute terms, we are talking about a risk of 2 per cent over 30 years.

    What of full-fat dairy? 5 servings of full-fat dairy a week are associated with better cardiovascular health. 2 servings of full-fat dairy have been associated with a 30 per cent decrease in the risk of metabolic syndrome as well as a 12 per cent reduction in diabetes risk.  For the cheese lovers out there, indulge; the evidence, like the Force, is with you.

    What of red meat, a rich source of protein, iron, vitamin C and other nutrients? The picture is more complex. Older studies have linked higher red meat consumption to the development of stomach and colon cancer, but more recent evidence suggests otherwise. Another large study found a slight increase in overall mortality with higher levels of unprocessed and processed meat but as above, the population studied already had multiple risk factors for heart disease and diabetes. Having said that, no one has explained why, if meat is so harmful, the people of Hong Kong have the highest meat consumption on the planet yet have a life expectancy of 84 years.

    The WHO in 2015 classified red and processed meat as direct carcinogens i.e. containing cancer-causing chemicals. A subsequent multi-country systematic review in 2017 suggested that the evidence to support the contention that unprocessed and processed meat was harmful to human health was of extremely low quality. Predictably this led to a scientific backlash, and more confusion on the part of consumers.

    None of these studies included the “gold-standard” randomised control trial with long-term follow-up that would be required to provide a definitive answer. They are mostly observational studies that come with their own significant limitations.

    We finally come to the former villain turned food superhero, dietary fat. Despite being essential for the production of hormones, cells and tissues in the body, and important for inducing satiety, it has been demonised for 60 years as a scourge on human health, as a result of deliberate data misrepresentation by an ambitious scientist.

    Vindication however is at hand; study after study after study indicate that saturated fat in the diet is not associated with stroke, heart attack or all cause mortality. It is the dietary consumption of “trans-fats” that is the concern . The blood levels of saturated fat have been associated with the development of heart disease, however these levels are not raised by a doubling of saturated fat in the diet and indeed it is the higher body synthesis of these fats, driven by excess processed carbohydrates, that is the issue.

    Higher carbohydrate levels in the diet actually increase the level of blood triglycerides, a more significant risk factor for heart disease than LDL cholesterol alone.

    Scientific evidence, not faith, should be the basis of public health policy and the evidence to support a tax on dairy or meat is lacking. PETA and others should be ignored on this issue.

    Corn, wheat and sugar are heavily subsidised by governments the world over. It’s time that these subsidies were either extended to dairy, poultry, meat and produce, or all subsidies abolished. Everyone deserves a genuine choice when it comes to the food they eat, and poverty should not be a reason a person cannot enjoy the highest quality food.