Peter Clifton is a Professor of Nutrition with a particular interest in the links between diet and the prevention and treatment of disease.
You’ve been involved with research into diet for many years now. It would seem to be an increasingly complex field.
It’s become complex because everyone has an opinion about diet and with the Internet there are now millions of people writing so there’s a lot of disinformation out there, deliberate or otherwise. Science these days has got a much harder task to either uncover the truth or, if they think they know what the answer is, to sell it with certainty. And I don’t think you can ever be certain about anything.
How have things changed over the years?
I don’t think it’s really changed the way I do things but it’s highlighted how difficult it is to intervene and get compliance and get meaningful answers that can be related to disease outcomes.
Is there a particular focus to your current work within ARENA?
One of my main projects is looking at type 2 diabetes, which is related to weight and to exercise but it’s the weight that has been the big driver. Many people can’t stop weight gain and they can’t lose weight. So my question is whether there is another way you can reduce your risk, even if it’s not going to be as good as losing weight. Dairy appears to be associated with less type 2 diabetes and processed red meat is associated with more. If this is true, it could be another way of reducing type 2 diabetes; drop your processed red meat, minimise your red meat and increase your dairy.
Most people probably wouldn’t link red meat to diabetes, which they associate with sugar.
That’s right, and the reason is difficult to understand. It may be just totally confounding. The people who are big dairy consumers and big red meat consumers may be doing something else in their life that we haven’t put a finger on that increases their risk. There’s lots of possible mechanisms.
Last year you launched a new research project looking at how effective a week-on, week-off diet may be in helping people lose weight and keep it off. What did the results show?
They show that it’s pretty much the same as being on continuous energy restriction. We hoped that psychologically it may be a better approach; rather than people feeling they are on a diet constantly they can say “this week will be my diet week and next week will be a normal week”. We thought that might be a better tool for compliance long term but it wasn’t, which is disappointing.
Is that possibly because people felt they were constantly starting a diet again?
To my mind it would seem better than saying every day is a diet day and I have to worry every single day about what I’m going to eat. It’s a bit like the “2 and 5”. Most people say “this is my two days of really severe dieting and the rest of the week I can just relax”, and that’s as effective as continuous dieting. We’re doing some studies at the moment in that area.
We tend to talk generically about “eating properly” but it’s obviously not as simple as that. How do you break down the components of an appropriate diet?
Probably the simplest answer is to say don’t have anything that comes from the centre of the supermarket where all the soft drinks and packets of salty and sweet things are. I don’t think anything in there is appropriate to be eaten on a daily basis; maybe weekly or fortnightly. So all of the things around the periphery of the supermarket that are more intact foods. And plant-based foods are more associated with good health than animal based foods – fewer diseases, longer life.
We read constantly about diet and diets; what frustrates you most about the conversations that Australians think they are having about diet?
Well I guess the thing about diet is that it’s always something people go on and go off, whereas if you want to lose weight you need to make a permanent change. That might be adopting “2 plus 5’’ indefinitely or dropping parts of your diet long term – taking out crisps, cake and biscuits, for example. Just making those kind of changes will make a profound difference to some people’s lives.
So you don’t have a silver bullet.
That’s right, there is no silver bullet; it’s multiple small bullets and they all have a small effect. Nothing is really powerful – and that’s the trouble about diet. Unlike a drug, where you can take it and find something really powerful, it’s actually quite hard to measure the effect of diet. You may have to change your diet for 30 years to get an impact.
Is there one that stands out for you. If you could get one dietary change into Australian society, what would it be?
One thing most people could manage would be replacing processed chips and Twisties and all those things with nuts. Whether it’s salted or unsalted probably is not critical. Nuts themselves are pretty good sources of proteins and healthy fats – and fibre if they are almonds. So just replacing crisps with nuts as a snack would make a difference to people’s health.