Chuck the chips, watch the witch

If you're planning on watching Eat Yourself Whole tonight, then ditch the bag of chips first.

Aside from all that saturated fat and salt, host and dietitian Nikki Hart would crucify you if she knew you were eating in front of the box. It goes against one of her golden rules, which also include not eating in the car or while standing.

"They're all things we're doing when we're distracted, when we're not concentrating on what we're eating," says Hart, who is known on the show as the Evil Diet Witch.

"It's amazing how a packet of Tim Tams will just disappear while you're watching a programme."

Starting tonight (TV2, 7.30pm), Hart will help ordinary New Zealanders - including nuclear families, single-parent households and teenagers - turn their lives around through nutrition.

"What I do is I jooge their fridge," Hart says gleefully. "Raiding a cupboard or a fridge is quite gratifying. I would like to think that New Zealanders eat well, but the fridges I've looked at have not been that flash. People are going to say, 'Thank goodness she didn't come to our house'."

Eat Yourself Whole is modelled on a programme made for the BBC but has no connection to You Are What You Eat, the British show that screens on Prime, where viewers learn that some people are "often constipated, lack energy, and have a low sex drive". But the Evil Diet Witch is not that mean and prefers to let cupboards and waistlines tell the story. She's also a realist who says there's no point joining a gym if you hate going, or completely giving up foods you love.

Hart spent four years training for a degree in consumer applied science, then 18 months as an apprentice dietitian and a further two years studying for a master's degree in nutritional science before opening her private practice in Auckland. She also works for Ironman and the Academy of Sport.

"People need to know the difference between a dietitian and a nutritionist because there's a lot of myths out there about nutrition," Hart says. "Because someone knows a wee bit about nutrition doesn't make them a medical expert. Dietitians are medically registered and you should come to us first rather than seeking what I call hocus-pocus advice."

Low-carb diets? Don't even go there. Hart says they're a "load or rubbish" and people have become terrified of "real foods".

Tonight, she introduces Merlin, a Harley Davidson-riding, hamburger-loving bloke who weighs a dangerous 143kg and has had two heart attacks.

Hart helps Merlin make healthy burgers, gives him a device that counts how many footsteps he makes in a day and tells him: "I'd like there to be less of you to love."

It's people such as Merlin, she says, that show the healthy eating message still isn't getting through - that's why 52 per cent of adult New Zealanders are obese.

"Obesity needs to be diagnosed as a disease and things like heart disease, high cholesterol, hypertension, diabetes - they come from the general umbrella of obesity. Unless we stem this obesity epidemic then all the other nutritional ramifications are going to hurt us. "I said to a professor many years ago that if I had half an hour with every New Zealander I would be sure I could change their diet. I think TV is the best medium to get all of New Zealand to watch because I can't get everyone in my office for half an hour."

* TV2, 7.30pm, tonight