Diet advice - what should you actually follow?

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The Hard Shoulder with Ciara Kelly and Shane Colman. On Newstalk with Kiya.

Shane Coleman (0:48)

Now when it comes to our diet, we seem to be constantly bombarded with evolving nutritional advice from new fads and trends to ultra processed foods and superfoods. So how do we cut through the noise and know who or what to believe? Well, Professor Christopher Gardner of St Stanford University has been researching nutrition for over 30 years and he's written a new book, Food Sense, which he said gives straightforward science back advice on what to eat and why. I'm delighted to say he is with us today. Professor Gardner, you're so welcome to the show.

What made you write the book, Food Sense?

Christopher Gardner (1:28)

Oh, because I'm so frustrated that there's a lot of stuff that we agree on and social media seems to suggest everything you thought you knew is wrong and those nutrition scientists never agree. And my perspective comes from 30 years of doing studies, being a professor, being on national health organizations.

And I participated with the American Heart Association, the Dietary Guidelines Advisory Committee, the American Diabetes Association, and others. And when we all sit in a room and we're looking at nutrition questions and we're looking at the data that are there, we almost always agree. And in fact, to change everybody's mind is really a slow process. Like, oh, yeah, it's the same as last time. And Shane, what's really probably the crux of the issue here, I think, comes up in a book that I just wrote that you mentioned, Food Sense, where I did a garlic study. And I would think that a natural public health question might be, is garlic good for me?

And I'm going to make this really short because I know we don't have a lot of time, but I studied one clove of garlic, either with fresh garlic or a garlic pill among people with high LDL cholesterol in the hopes that after six months, it would lower their cholesterol. And it did not. And when it didn't, some supplement companies called me and said, you used the wrong supplement. You should do the whole trial over and use mine. And a farmer called me and said, oh, I grow 90 kinds of variety, 90 varieties of garlic. Did you try them all? Because I can give you them all if you'll do the study all over again.

And somebody else said, yeah, but what about blood pressure? What about inflammation? What about if it was two or three cloves, not one clove? What if it was, oh my god, everybody.

The way I did the science study and the way I have to is one dose for one population for one amount of time for one outcome. And I understand how all the other questions are important, but we usually don't have all the answers. And I actually think the more interesting thing is, are you eating garlic in hummus, or are you eating, I don't know if you guys, it's in Ireland, but boy, we have garlic French fries here.

Shane Coleman (3:47)

Yeah.

Christopher Gardner (3:47)

I think that would be a big difference between garlic French fries.

Shane Coleman (3:50)

Yeah, I can see that.

Christopher Gardner (3:51)

And hummus.

Shane Coleman (3:53)

So are we overcomplicating it?

Christopher Gardner (3:57)

So sometimes I'm also super frustrated. In the US is a guy named Michael Pollan, who 20 years ago wrote a book called Omnivore's Dilemma. And he came up with this saying in seven words, eat food, not too much, mostly plants. And Shane at the end of many of my lectures, after I've cited many papers and I've shown biochemical pathways, and I've given logical reasoning, somebody says, look, we just listened to you for an hour. Can you sum it up for me?

And I said, well, yeah, eat food, not too much, mostly plants. And this journalist wrote that, I think it's brilliant. And on the other hand, it's like, I can't get away with that as a scientist, I would have to provide scientific citations and a whole rationale for it. But he did such a nice job of making it simpler. And so most of it's pretty simple. You guys have, in the UK, somebody wrote this great book about ultra processed people.