We're also in danger of passing on our sugar addiction to future generations.

Sarah Wilson, journalist and author of I Quit Sugar, an eight-week program of eating without sugar, practices what she preaches.

According to Wilson “one of the big things I noticed when I quit sugar was that I got clearer in my head, my energy was more even, and I guess I became a nicer person.”

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Australians are pigging out on more and more sugar-laden fatty foods. Now the new scientific evidence says we're not just damaging our health, but also the health of future generations.

Dr Amanda Sainsbury-Salis from the Garvan Institute of Medical Research says “the high levels of fat and sugar we are consuming in our diet today affects our DNA, and this can be passed onto our progeny - to our children and our children’s children.”

Currently two in three Australian adults are overweight, one in five obese, and the rates have actually doubled in seven years. We are passing on that sugar and fat addiction to our kids, along with illnesses like high blood pressure, diabetes, heart disease, hormone imbalances and liver damage.

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Sugar and fat-filled foods are the biggest sellers in the supermarkets - sauces, confectionary, cakes, pastries, cordials, soft drinks and fruit drinks. In the 19th century, our diets included about one kilogram of sugar a year - mainly found in fruit. Now we're eating as much as 50 kilograms a year - about one kilogram a week.

Matt O'Neil nutritionist at Metabolic Jumpstart says “the average person is eating about 28 teaspoons of sugar a day. It's a phenomenal amount. A healthy target you can achieve with a balanced diet is about ten teaspoons of sugar - that's 50 grams a day.”

According to O'Neil “there is no doubt sugar is addictive, like a drug. People need their sugar fix, and their hit.”

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Dr Sainsbury-Salis is calling for regulations controlling our overconsumption of fatty, sugary foods, because of the changes they cause to the DNA chemicals.

“Even if your children eat the healthiest diet in the world, they can have a higher predisposition towards problems such as excess weight, diabetes and athrosclerosis,” she said.

Wilson suffered an auto-immune disease but transformed her life by quitting sugar.

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“We've got the emotional addiction, and of course the physical addiction, and both have been proven as existing. I found that it took about six to eight weeks to break both sorts of habits,” Wilson said.

She wrote the book on the eight-week program, which has been followed by 15,000 others.

“The biggest thing that most people would notice is the clearness in the head. They wake up with a clear mind, and it continues for the whole day,” Wilson said.

• A nut bar - a teaspoon and a half of sugar
• 50 grams of dried fruit - four teaspoons of sugar
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• 250 millilitre glass of juice - five teaspoons of sugar

What we crave is fructose - the added sugar in sweets, some yogurts and cereals. The danger is that fructose can only be processed by the liver, and stored as fat.

“When you drink a glass of apple juice, it's going to your liver as pure fat the instant that you actually put it in your mouth. On top of that your brain, body and metabolism isn't actually registering that you're drinking or eating something, so we keep eating,” O’Neill explained.

For Teresa Apple, Natvia was the answer. Natvia is a natural sweetener made from plants, stevia and nectars. Just 0.6 calories per serve, you only need minute amounts for sweetness.

“Sugar is toxic to my system. It causes digestive problems and gives me headaches,” Apple said.

“Natvia doesn't have the aspartame, the chemicals, the artificial colours and flavourings, the things that I want to avoid in my diet. With sugar you can get the high sugar high, but then you get the crash afterwards. You avoid that when you use Natvia.

“I can use it in baking and cooking. We use it in our coffee and tea. I feel lighter and I don't get the headaches. I don't have all the digestive issues,” she said.

O’Neill says we do need some sugar in our diet. “It gives us energy and it fuels our brain. But if you overdo it, the consequences are a bigger waistline and obesity.”

• Metabolic Jumpstart - www.metabolicjumpstart.com
• Garvan Institute's Associate Professor Amanda Sainsbury-Salis - www.garvan.org.au
• Natvia - www.natvia.com
• I Quit Sugar by Sarah Wilson - www.sarahwilson.com.au