How’s this for a radical diet – eat more bacon and watch the weight drop off? It is a little more complex than that, but the message is pretty simple: Ignore what the experts have been telling you. Saturated fat is good for you.
This controversial new approach though is leading to one hell of a food fight, involving some of the country’s most esteemed health academics.
"When you start eating carbs, you start burning carbs, and when you start eating fat, you start burning fat," says Grant Schofield, professor of public health at AUT.
Professor Schofield’s discovery began in his work with athletes, but he believes the theory applies equally to the rest of us.
In 30 cases now people have been put in randomised control trials where people are on different types of diets. They have eaten diets that are low in carbohydrates but high in fat, and that includes a deal of saturated fat, all of their cardiovascular risk factors, the things that everyone in medicine agrees affects your health, but they improve.
Professor Schofield has an advocate in dietician Dr Caryn Zinn, who has given us some ideas on how you would eat their low-carb high-fat way.
"For some people who don't like getting that kind of fat, they can still cut it off and get their fat from elsewhere, but it's actually fine to eat if you're not eating sugar," says Dr Zinn.
"Fat makes food taste nice. It adds the flavour. It's the same as skin off chicken."
Sera Lilly has been a fashion designer for a long time. She was overweight in an industry full of thinness.
"I was 118kg when I weighed in," she says. "I could possibly have been more. "My doctor said gastric bypass surgery, which is very available, a year and a half ago. I’m 30 this year so maybe 28."
What she embarked on instead of surgery was a low-carb, high-fat diet. Documenting her dramatic progress on social media, and in the process quickly gaining thousands of followers, she watched herself lose nearly 40kg.
"I do [feel good], but it’s taking a while for my mind to catch up to my body. I sometimes feel a lot heavier than I am and I sometimes walk in a mall and catch a glimpse of myself and think, 'Who is that? She looks nice.' But it’s me."
Meet the nemesis of the high saturated fat school of thought – University of Otago professor in human nutrition Jim Mann, who is profoundly against the concept that saturated fat could be good for you.
"There is one thing I would never concede, and that is that it's okay to have as much saturated fat as you'd like," says Professor Mann. "There is no evidence whatsoever that a high intake of saturated fat is good. And in fact there is a lot of evidence that a high intake of saturated fat is bad. It's very hard to find any positives about butter in terms of its impact on cardiovascular disease."
But actually in recent weeks and months internationally, this argument has blown up in the scientific community, with claim and counter-claim about the benefits or dangers of saturated fat.
So should you or shouldn’t you? The pro saturated fat camp says the key is to take out most carbohydrates, especially processed carbs, which they believe have fed the obesity epidemic. But you have got to replace that energy with something, so they say eat fat, including saturated fat.
And cholesterol? They argue it’s not the evil we’ve been led to believe it is. They say every cell in our body needs it and the thinking around good and bad cholesterol is out of date.
The anti- camp is adamant that's wrong, repeating its decades-long message of the link between saturated fat, bad cholesterol and heart disease.
It is enough to make a trip to the supermarket a conundrum.
"There are a very limited number of people that understand the literature who would actually say we’ve got it wrong in terms of saturated fat, and what is more not only is there a general consensus about that, but actually the reduction in cardiovascular disease is directly proportional to the reduction in cholesterol, which occurs as a result of the reduction in saturated fat," says Professor Mann.
"I’m referring to randomised control trials, which take into account whether people smoke or not, whether people are on statins or not, and in fact some of those trials anti-date statins. There are trials which were conducted before statins, which involve a reduction in saturated fat and an increase in polyunsaturated fat."
Try telling that to ex-dairy farmer Garth Scown. When the experts said reduce your saturated fat, he started eating more of it.
"I eat a lot of butter," he says.
Mr Scown also gulps down a litre and a half of milk a day – silver top, of course, part of his steadfast devotion to saturated fat.
"I'm walking experiment number one. It’s been successful, very successful."
The mere sight of Rod Jackson’s lunch is an indication of just how much he would disagree.
"Sprouts I sprouted myself, raw carrots, beetroot from my garden, some almonds, some tomatoes and right throughout it, feta cheese," says Professor Jackson.
A University of Auckland epidemiologist, Professor Jackson is known to his students as the anti-butter professor. His message is pretty clear of the link between saturated fat and heart disease.
But not all the scientists agree.
"Have they been to the local supermarket or south Auckland, or to a rugby match recently and had a look at the public, or been to a local hospital and had a look at the dialysis and diabetes and cancer?" asks Professor Schofield.
"Heart disease mortality is down by 80 percent," says Professor Jackson. "That’s heart disease mortality. Life expectancy of New Zealanders is increasing at about six hours a day. In terms of getting fatter, we are getting fatter but very slowly, on average about half a BMI unit over 10 years.
"We’re not getting fatter because of the current advice; we’re getting fatter because food has never been cheaper, never been more available – 24 hours a day. So the reason we’re getting fatter is we’ve got lots of cheap food and it tastes good."
The problem is they can all sound like they are making sense. So whom should you listen to?
Professor Jackson says epidemiologists would be the people you would go to first.
"I’m a professor in public health," says Professor Schofield. "I’ve got my PhD in physiology and psychology, but I’ve spent my whole career in diabetes prevention. But in the exercise side, I didn’t mean to get into nutrition. We’ve been drawn in because of where we think the evidence is."
An elite sportsman has more reason than most of us to look after his body. So what is New Zealand cricketer Mitchell McClenaghan doing eating more saturated fat, not less?
For the past three years he has followed what is known as the paleo diet, eating more like our ancestors, dropping grains and eating much more fat.
"For the way I play my cricket, I go balls to the wall all the time and I feel like I can do that all day just because my insulin levels aren’t spiking or having big dips and lows," he says. "I was about 110kg and lost about 15kg and got down to 95kg. I just felt more energy. I was more mobile. I was functioning really well mentally. I think that’s a huge component of the high-fat content."
The no-grain paleo diet is what the pro saturated fat people say provides some of the long-term evidence they need.
"If you look over the last two and a half million years where humans have been evolving, let’s have a look at what they’ve eaten," says Professor Schofield. "They’ve eaten whole plants and animals – food that would rot – and they were metabolically healthy."
"Frankly I think this is the biggest red herring to be polite – garbage to be a bit less polite," says Professor Mann. "Your ancestors and mine, wherever they came from, were jolly lucky if they lived to be 40.
"What I’m saying is it shouldn’t be introduced into the argument because they haven’t got any data. I’m not saying that I’m using it as an argument to say any kind of diet is healthy; I’m simply saying that there is nothing in the argument to say it’s good."
"I can understand why putting a label like paleo does that because I have no idea of the exact foods that my ancestors ate," says Professor Schofield. "But we’re not talking about the paleo diet. We’re talking about taking an evolutionary biology perspective and understanding human metabolism and nutrition.
"Honestly guys, you would reject two and a half million years of human evolution and understanding how human metabolism works and just go with the food pyramid?"
Dr Zinn might be a bit of a pariah in her field. She has done a complete 180 on the food pyramid concept she has been teaching for 20 years.
"Normally [for breakfast] I have an omelette with lots of vegetables, but this morning I actually had some berries, with two types of thick, creamy high-fat yoghurt and I had a dessert spoon of high-fat almond butter scooped on top," says Dr Zinn. "I topped it off with instant coffee with cream."
"I’ve got good genes but it’s important to remember that fat doesn’t actually make you fat," says Dr Zinn.
But for us, the public, the two polar opposite views leave us with very little left.
"I'm sorry," says Professor Mann. "I don’t think there is conflicting advice. All these new ideas are as old as the hills and nobody has come out with any good substantiation of them.
"They need to get on and produce that evidence, and I would argue producing that evidence before they try to persuade the world that they’ve got the answer."
"This science will evolve," says Professor Schofield. "I will shift my opinion a bit. I think Jim will shift his opinion a bit and we’ll end up in the same place."
- Reporter: Paula Penfold
- Producer: Eugene Bingham
- Editor: Paul Enticott
our story Food Fight, we said that retired dairy farmer Garth Scown was
69 years old. In fact, he is 74, turning 75 in June. We apologise for our