Referring to herself as a “last resort”, Ms Jackson is used to sceptics. Speaking at an AIM WA luncheon as part of the Your Best Self Series, Ms Jackson said a client of hers – critically acclaimed actor and filmmaker Mel Gibson – once phoned her at 1am to grill her on nutrition advice.

“It says a handful of blueberries – how much is that?,” the Braveheart star asked her.

According to Ms Jackson, the Hollywood icon had been through a number of failed diets and wanted to prove her advice also wouldn’t work, no matter how precisely he followed instructions.

“But then, on day eight, I got a text message from him saying holy expletive, my pants are loose,” she laughed. Following Ms Jackson’s eating and fitness suggestions, Mr Gibson shed 14kg in an eight-week period.

She stressed the Mad Max lead did not go vegan, stop eating or spend all day exercising – instead she advised him to indulge in an old-fashioned mix of protein, carbohydrates, good fats and muscle building.

“Sometimes we say, ‘look, I probably eat around 2000 calories a day, so I’m going to eat 1200 calories a day and lose weight that way’,” Ms Jackson said.

“And you will, there’s no doubt about it. Losing weight via a caloric deficit will work… temporarily.

“But what happens is you’re restricting energy and nutrients and you’re also losing muscle which controls your metabolic weight. If you lose muscle your body is not going to be using energy as effectively.

“The more muscle mass you have, the more effectively you’ll burn energy and fat. It’s really that simple.”

Dashing a whole host of health and fitness myths, Ms Jackson described the importance of lifting weights – even just a can of beans during television ad breaks – to prevent the slowdown of metabolism. 

She dismissed the demonising of carbohydrates, said the average protein portion should be the length and thickness of a hand and made a clear distinction between two types of body fat – “one,” she said, “won’t hurt you”.

“Subcutaneous fat is anything between the skin and muscle and it won’t hurt you, unless you have too much of it and it’s putting pressure on your cardiovascular system,” Ms Jackson said.

“But as a substance it’s harmless, unlike its mate visceral.

“If you don’t look after your diet, you accumulate visceral fat, which is nasty and toxic.

“If you have more than 500g of it, you’re at risk of about 13 types of cancer, Alzheimer’s disease, Type 2 Diabetes, stroke, fatty liver and loads of cardiovascular issues.

“To shrink visceral fat, get rid of excess sugar, saturated and trans fats and alcohol.”

Ms Jackson also cautioned against juicing, warning that liquefying foods concentrated sugar and forced the fibre out, meaning a cup of “green juice” could have the same effect on the body as a pack of jelly snakes.

She called for the end to the sensationalist language surrounding food and fad diets and named education as the answer to busting health misconceptions.

“Back in the 1830s a Belgian astronomer invented the BMI (Body Mass Index) and, quite frankly, that’s where it should stay,” Ms Jackson said.

“It is the most outdated, antiquated, ridiculous measure. Let’s say a person has 65 per cent fat in their body and 30 per cent is muscle.

“They do a whole lot of work on themselves and go through a beautiful health transformation.

“Now they have 65 per cent muscle, 30 per cent fat, but they still weigh a 100 kilos, even though their health has improved remarkably.

“They’re going to look different, feel different, their health risks will be through the floor and yet the BMI still puts them in the obese category because the person didn’t change their height.

“That’s the biggest flaw with the BMI and the mentality that what we weigh on the scales is valid.”

Ms Jackson encouraged people to focus less on weight and more on achieving a healthy body composition, made easy through exercise and eating good ratios of proteins, fats, carbohydrates, vitamins and minerals and drinking plenty of water.

“Remember, the human body is designed to feel spectacular,” she said.
“So, aim for that.”