The new skinny on diets gives Noakes an equal weighting
American study shows low-carb and low-fat diets are perhaps not as different as people think
The longstanding debate between controversial low-carb guru Tim Noakes and followers of a more traditional low-fat diet could end up with both sides being right.
Leading Stanford University researchers compared a low-fat and low-carbohydrate diet in more than 600 overweight Americans for a year, to see which one worked better for weight loss.
Both groups lost almost the same amount of weight: the low-carb group lost on average 6kg and the low-fat group 5.3kg.
Christopher Gardner, lead author of the study and Stanford professor of medicine, said of the conclusion: “Maybe we shouldn’t be asking what’s the best diet, but what’s the best diet for whom.”
Gardner noted that both had a lot in common, showing that low-fat and low-carb diets were perhaps not as different as people think.The key to weight loss, according to researchers, was eating food of high quality.
Salmon, avocado and nuts were the types of food suggested for the high-fat group, and brown rice, lentils, legumes, lean meat and oats were promoted for the low-fat group.
“We made sure to tell everybody, regardless of which diet they were on, to go to the farmer’s market and don’t buy processed convenience food crap," Gardner said.It's not in the genes
The participants also had parts of their DNA sequenced to see if genetics or popular DNA diets could predict whether a certain diet would be better for an individual. The genes tested made no difference to weight loss.
Hannah Wardill, a cancer researcher at the University of Adelaide, said that for now “you can’t quite blame your genes for not fitting in to your favourite jeans ... Unfortunately, the study has not taken us any closer to personalising weight loss strategies.”The 609 overweight America adults, split almost evenly between men and women, were randomly assigned to each group and followed the diet for a year, with a 20% dropout rate.In the long run
The study also suggests that diets have to be sustainable, something they could do for life.
For the first two months, the low-carb group started eating only 20 grams of carbs (the equivalent of about 1,5 slices of bread) a day. The low-fat group had to consume less than 20 grams of fat.But by month three the participants were told to eat as few carbs or fats as they could manage in order to continue with their eating habits for the rest of their lives.
Most people in the low-carb could only manage eating 132 grams of carbohydrate a day, above what low-carb diet promoters such as Noakes suggest.High-fat author and Noakes’s friend Gary Taubes, whose organisation helped sponsor the study, said the high-fat diet tested had not been a true ketogenic diet. This is when people eat less than 30 grams of carbs a day.
But he tweeted afterwards that thinking about high-fat diets was becoming more mainstream.
“The debate used to be whether low-carb diets were deadly. Now it’s whether low-fat diets are as good as low-carb (at least when both are restricted in sugar and high-GI grains). That’s progress.”
The professor of public health at Griffith University, Dr Lennert Veerman, also weighed in on the study, saying it concluded that “there is probably no such thing as a diet that is right for your particular genetic make-up”.
“The fact that the diets led to similar weight loss confirms earlier research that suggested that it doesn’t much matter what diet you follow – it all comes down to consuming fewer calories.”
He advised people wanting to shed weight: “A good rule of thumb is to avoid energy-dense foods and drinks. We eat to fill our stomach, and if that’s with vegetables we tend to lose weight, whereas if it’s with chocolate or French fries, flushed down with a soda, we gain weight.”High-fat high-five for Noakes
As Professor Tim Noakes awaits the Health Professions Council of SA ( HPCSA) ruling on whether he is guilty of misconduct, support for him continues to swell.
More than 32,000 doctors and fans have signed a petition at Change.org in support of him, but an organisation has also spent advertising dollars to extend its reach.
Noakes, a registered doctor, was charged with giving unconventional advice that was not evidence-based after he suggested in a tweet that a mother wean her baby onto a low-carb, high-fat diet.
He won his case at the HPCSA in 2017, but the body is appealing the ruling. Judgment is expected within the next three weeks.The petition continues to gather signatures even after the appeal against Noakes was completed on Friday.
It states: “The greater knowledge there is around the world of the latest scientific evidence, the better off we will all be, and hopefully the fewer frivolous attacks there will be against professionals like Tim Noakes.”The latest person to sign the petition is Walter Willett, professor of epidemiology and nutrition at Harvard Medical School, according to the Nutrition Coalition who set it up.
The coalition describes itself as a non-profit, non-industry-funded group that seeks to promote evidence-based policy.
It paid to advertise the petition on social media networks such as Twitter to gather support.
The petition says Noakes’s diet is supported by science and he is being victimised by the HPCSA.
“He became famous in South Africa for promoting the diet – and this led to various forms of retaliation by his colleagues. Perhaps most stunning, however, has been that medical authorities (HPCSA) have subjected Professor Noakes over the past few years to a public hearing, with his medical licence hanging in the balance.”
Sarah Hallberg, of the coalition's Scientific Advisory Council, said the coalition and a group of independent doctors helped launch the petition, “principally in defence of science”, which “clearly shows a low-carbohydrate diet to be safe and effective”.
The organisation would not say where it raised the money and how much it spent advertising the petition, although it said no funding came from industry.
The coalition “is an independent, science-based group that exists purely in the public interest, free from any industry interest. (It) is funded by hundreds of individual donors and does not accept support of any kind from any interested industry,” Hallberg said.
– Katharine Child