Robyn Toomath is interviewed on Stuff today. She's certainly got one thing right - the increasing obesity rates aren't demonstrating some unexplained decline in willpower across the West, they're to do with the food people are eating.
Toomath, who in her photo on Stuff has the dry, wrinkly skin and lank hair of someone who doesn't get anything like enough fat in their diet, has business-as-usual "expertise" to contribute on the subject of what to do about obesity:
A fat tax, subsidised fruit and veges, school bans on tuckshops selling junk food, advertising regulations – she has backed them all.
Of course, nutritionists and public health professionals have been peddling this eat-less-fat, eat-more-veg message for decades now - as it happens, since around the time the obesity epidemic took off.
Most of these people are aware of the facts around weight gain: that fat metabolism is driven by insulin, and insulin is driven by carbohydrates. However, the academics' and public health specialists' "absolutely boring, bread-and-butter, routine stuff" is that people need to eat less fat, which means they've spent decades now promoting high-carbohydrate diets, and yet can't figure out why people are getting fatter despite consuming fewer calories than they did back when a fatty cut of meat was the cornerstone of the Western diet.
It's called cognitive dissonance:
1. We know that fat metabolism is driven by insulin, which is driven by carbohydrates.
2. Let's recommend a high-carbohydrate diet to make people less fat.
If you can explain it, good luck to you. I suspect it's one of Kuhn's "scientific revolution" things - you can see there's something wrong with the hypothesis, but as long as it's business-as-usual for the big reputations in the field, you'd better assume a lack of understanding on your part.