Why is diet advice so confusing?

Low fat, high protein, no carbs, high fat… modern society gives us a myriad of messages about how, when and what to eat, whether we’re looking to lose weight, or just be a little bit healthier. It’s no wonder that many people are confused, and that goes for the ‘experts’ as well as the ordinary (wo)man in the street.

Modern diets really took off in 1863 when English undertaker William Banting published his ‘Letter on Corpulence’ – the regime on which he lost more than four stone. Banting’s meat, fish, game and low carb advice became an instant bestseller, but he also came under fire from the medical establishment for having no authority on which to base his claims (despite the fact that his diet was devised by his doctor, and it actually worked).

Scorn is often heaped on diet plans that don’t follow the current ‘official’ theory in both the UK and US: that carbs are the major stars of a healthy diet, while fats are relegated to a tiny walk-on role. The US National Academy of Sciences, American Medical Association, American Cancer Society and others all oppose the Atkins Diet, for example, because of its fat levels and lack of carbs. Don’t forget the uproar at the end of 2016, when the Public Health Collaboration criticised current government nutritional guidelines and suggested that we return to ‘old-fashioned, full-fat real foods’, – cheese, nuts, avocados, meat, vegetables and fruit. The resulting censure complained their report risked ‘endangering public health’ because it embraced fat.

To find out where our government’s current carb obsession comes from, you need to take a trip back to World War II, when US nutritionist Ancel Keys devised the rations that kept the  US military moving, as well as a theory that dietary fat causes heart disease. Despite this link never having been proven in a clinical trial, it sparked an anti-fat campaign that by the 1980s was responsible for a massive increase in carbohydrate consumption throughout the Western world.

Government guidelines continue to trot out the same old message: limit animal products, limit fat, eat more plant foods – using weak science drawn mainly from reviews by the American Heart Association and the American College of Cardiology (both heavily supported by Big Food and Big Pharma) and ignoring data on the benefits of carb reduction for weight loss, control of Type 2 diabetes and reducing the risk of heart disease.

And during the decades of this low-fat, high-carb advice, as a population we have become obese.

So who can you trust? Dietician Kathryn Hart makes a very good point: “Nutrition is a constantly evolving science and new research may uncover new evidence.”

But with so many vested interests in supporting the “fat is bad, carbs are good” mantra, perhaps it’s not surprising that anyone who disagrees, be they scientist, doctor, researcher or obese person, is likely to be shot down in flames.